The impact of long-term PM2.5 exposure on specific causes of death: exposure-response curves and effect modification among 53 million U.S. Medicare beneficiaries

Associations between PM2.5 Components and Mortality of Ischemic Stroke, Chronic Obstructive Pulmonary Disease and Diabetes in Beijing, China

Ischemic stroke (IS), chronic obstructive pulmonary disease (COPD) and diabetes mellitus (DM) account for a large burden of premature deaths. However, few studies have investigated the associations between fine particular matter (PM2.5) components and mortality of IS, COPD and DM. We aimed to examine these associations in Beijing, China. Data on daily mortality, air pollutants and meteorological factors from 2008 to 2011 in Beijing were collected. Daily concentrations of five PM2.5 components, namely, sulfate ion (SO42-), ammonium ion (NH4+), nitrate ion (NO3-), organic matter (OM) and black carbon (BC), were obtained from the Tracking Air Pollution (TAP) database in China. The association between PM2.5 components and daily deaths was explored using a quasi-Poisson regression with the distributed lag nonlinear model (DLNM). The average daily concentrations of SO42-, NH4+, NO3-, OM and BC were 11.24, 8.37, 12.00, 17.34 and 3.32 μg/m3, respectively. After adjusting for temperature, relative humidity, pressure, particulate matter less than 10 μm in aerodynamic diameter (PM10), nitrogen dioxide (NO2) and sulfur dioxide (SO2), an IQR increase in OM at lag day 2 and lag day 6 was associated with an increased DM mortality risk (RR 1.038; 95% CI: 1.005-1.071) and COPD mortality risk (RR 1.013; 95% CI: 1.001-1.026). An IQR increase in BC at lag day 0 and lag day 6 was associated with increased COPD mortality risk (RR 1.228; 95% CI: 1.017-1.48, RR 1.059; 95% CI: 1.001-1.121). Cumulative exposure to SO42- and NH4+ was associated with an increased mortality risk for IS, with the highest effect found for lag of 0-7 days (RR 1.085; 95% CI: 1.010-1.167, RR 1.083; 95% CI: 1.003-1.169). These effects varied by sex and age group. This study demonstrated associations of short-term exposure to PM2.5 components with increased risk of IS, COPD and DM mortality in the general population. Our study also highlighted susceptible subgroups.

Exposure-Response to High PM 2.5 Levels for Cardiovascular Events in High-risk Older Adults in Taiwan

Background

Multiple studies from countries with relatively lower PM 2.5 level demonstrated that acute and chronic exposure even at lower than recommended level, e.g., 9 μg/m 3 in the US increased the risk of cardiovascular (CV) events. However, limited studies using individual level data exist from countries with a wider range of PM levels to illustrate shape of the exposure-response curve throughout the range including > 20 μg/m 3 PM 2·5 concentrations. Taiwan with its policies reduced PM 2.5 over time provide opportunities to illustrate the dose response curves and how reductions of PM 2.5 over time correlated with CV events incidence in a nationwide sample.

Methods

Using data from the 2009-2019 Taiwan National Health Insurance Database linked to nationwide PM2.5 data. We examined the shape and magnitude of the exposure-response curve between seasonal average PM 2·5 level and CV events-related hospitalizations among older adults at high-risk for CV events. We used history-adjusted marginal structural models including potential confounding by individual demographic factors, baseline comorbidities, and health service measures. To quantify the risk below and above 20 μg/m 3 we conducted stratified Cox regression. We also plotted PM 2.5 and CV events from 2009-2019 as well as average temperature as a comparison.

Findings

Using the PM 2.5 concentration <15 μg/m 3 (Taiwan regulatory standard) as a reference, the seasonal average PM 2.5 concentration (15-23.5μg/m 3 and > 23.5 μg/m 3 ) were associated with hazard ration of 1.13 (95%CI 1.09-1.18) and 1.19 (95%CI 1.14-1.24), 1.07 (95%CI 1.03-1.11) and 1.14 (95%CI 1.10-1.18), 1.22 (95%CI 1.08-1.38) and 1.31 (95%CI 1.16-1.48), 1.04 (95%CI 0.98-1.10) and 1.10 (95%CI 1.04-1.16) respectively for HF, IS/TIA,PE/DVT and MI/ACS. A nonlinear relationship between PM 2·5 and CV events outcomes was observed at PM 2·5 levels above 20 μg/m 3 .

Interpretation

A nonlinear exposure-response relationship between PM2·5 concentration and the incidence of cardiovascular events exists when PM2.5 is higher than the levels recommended by WHO Air Quality Guidelines. Further lowering PM2·5 levels beyond current regulatory standards may effectively reduce the incidence of cardiovascular events, particularly HF and DVT, and can lead to tangible health benefits in high-risk elderly population.

Cluster pattern analysis of environmental stressors and quantifying their impact on all-cause mortality in Belgium

Environmental stress represents an important burden on health and leads to a considerable number of diseases, hospitalisations, and excess mortality. Our study encompasses a representative sample size drawn from the Belgian population in 2016 (n = 11.26 million, with a focus on n = 11.15 million individuals). The analysis is conducted at the geographical level of statistical sectors, comprising a total of n = 19,794 sectors, with a subset of n = 18,681 sectors considered in the investigation. We integrated multiple parameters at the finest spatial level and constructed three categories of environmental stress through clustering: air pollution, noise stress and stress related to specific land-use types. We observed identifiable patterns in the spatial distribution of stressors within each cluster category. We assessed the relationship between age-standardized all-cause mortality rates (ASMR) and environmental stressors. Our research found that especially very high air pollution values in areas where traffic is the dominant local component of air pollution (ASMR + 14,8%, 95% CI: 10,4 - 19,4%) and presence of industrial land (ASMR + 14,7%, 95% CI: 9,4 - 20,2%) in the neighbourhood are associated with an increased ASMR. Cumulative exposure to multiple sources of unfavourable environmental stress (simultaneously high air pollution, high noise, presence of industrial land or proximity of primary/secondary roads and lack of green space) is associated with an increase in ASMR (ASMR + 26,9%, 95% CI: 17,1 - 36,5%).

Association of air pollution exposure and increased coronary artery disease risk: the modifying effect of genetic susceptibility

BACKGROUND

Both genetic factors and air pollution are risk factors for coronary artery disease (CAD), but their combined effects on CAD are uncertain. The study aimed to comprehensively investigate their separate, combined and interaction effects on the onset of CAD.

METHODS

We utilized data from the UK Biobank with a recruitment of 487,507 participants who were free of CAD at baseline from 2006 to 2010. We explored the separate, combined effect or interaction association among genetic factors, air pollution and CAD with the polygenic risk score (PRS) and Cox proportional hazard models.

RESULTS

The hazard ratios (HRs) [95% confidence interval (CI)] of CAD for 10-µg/m3 increases in PM2.5, NO2 and NOx concentrations were 1.25 (1.09, 1.44), 1.03 (1.01, 1.05) and 1.01 (1.00, 1.02), respectively. Participants with high PRS and air pollution exposure had a higher risk of CAD than those with the low genetic risk and low air pollution exposure, and the HRs (95% CI) of CAD in the PM2.5, PM10, NO2 and NOx high joint exposure groups were 1.56 (1.48, 1.64), 1.55(1.48, 1.63), 1.57 (1.49, 1.65), and 1.57 (1.49, 1.65), respectively. Air pollution and genetic factors exerted significant additive effects on the development of CAD (relative excess risk due to the interaction [RERI]: 0.12 (0.05, 0.19) for PM2.5, 0.17 (0.10, 0.24) for PM10, 0.14 (0.07, 0.21) for NO2, and 0.17 (0.10, 0.24) for NOx; attributable proportion due to the interaction [AP]: 0.09 (0.04, 0.14) for PM2.5, 0.12 (0.07, 0.18) for PM10, 0.11 (0.06, 0.16) for NO2, and 0.13 (0.08, 0.18) for NOx).

CONCLUSION

Exposure to air pollution was significantly related to an increased CAD risk, which could be further strengthened by CAD gene susceptibility. Additionally, there were positive additive interactions between genetic factors and air pollution on the onset of CAD. This can provide a more comprehensive, precise and individualized scientific basis for the risk assessment, prevention and control of CAD.

Associations of long-term fine particulate matter exposure with all-cause and cause-specific mortality: results from the ChinaHEART project

Background

The chronic effects of fine particulate matter (PM2.5) at high concentrations remains uncertain. We aimed to examine the relationship of long-term PM2.5 exposure with all-cause and the top three causes of death (cardiovascular disease [CVD], cancer, and respiratory disease), and to analyze their concentration-response functions over a wide range of concentrations.

Methods

We enrolled community residents aged 35-75 years from 2014 to 2017 from all 31 provinces of the Chinese Mainland, and followed them up until 2021. We used a long-term estimation dataset for both PM2.5 and O3 concentrations with a high spatiotemporal resolution to assess the individual exposure, and used Cox proportional hazards models to estimate the associations between PM2.5 and mortalities.

Findings

We included 1,910,923 participants, whose mean age was 55.6 ± 9.8 years and 59.4% were female. A 10 μg/m3 increment in PM2.5 exposure was associated with increased risk for all-cause death (hazard ratio 1.02 [95% confidence interval 1.012-1.028]), CVD death (1.024 [1.011-1.037]), cancer death (1.037 [1.023-1.052]), and respiratory disease death (1.083 [1.049-1.117]), respectively. Long-term PM2.5 exposure nonlinearly related with all-cause, CVD, and cancer mortalities, while linearly related with respiratory disease mortality.

Interpretation

The overall effects of long-term PM2.5 exposure on mortality in the high concentration settings are weaker than previous reports from settings of PM2.5 concentrations < 35 μg/m³. The distinct concentration-response relationships of CVD, cancer, and respiratory disease mortalities could facilitate targeted public health efforts to prevent death caused by air pollution.

Funding

The Chinese Academy of Medical Sciences Innovation Fund for Medical Science, the National High Level Hospital Clinical Research Funding, the Ministry of Finance of China and National Health Commission of China, the 111 Project from the Ministry of Education of China.

Long-term mortality burden trends attributed to black carbon and PM2·5 from wildfire emissions across the continental USA from 2000 to 2020: a deep learning modelling study

BACKGROUND

Long-term improvements in air quality and public health in the continental USA were disrupted over the past decade by increased fire emissions that potentially offset the decrease in anthropogenic emissions. This study aims to estimate trends in black carbon and PM2·5 concentrations and their attributable mortality burden across the USA.

METHODS

In this study, we derived daily concentrations of PM2·5 and its highly toxic black carbon component at a 1-km resolution in the USA from 2000 to 2020 via deep learning that integrated big data from satellites, models, and surface observations. We estimated the annual PM2·5-attributable and black carbon-attributable mortality burden at each 1-km2 grid using concentration-response functions collected from a national cohort study and a meta-analysis study, respectively. We investigated the spatiotemporal linear-regressed trends in PM2·5 and black carbon pollution and their associated premature deaths from 2000 to 2020, and the impact of wildfires on air quality and public health.

FINDINGS

Our results showed that PM2·5 and black carbon estimates are reliable, with sample-based cross-validated coefficients of determination of 0·82 and 0·80, respectively, for daily estimates (0·97 and 0·95 for monthly estimates). Both PM2·5 and black carbon in the USA showed significantly decreasing trends overall during 2000 to 2020 (22% decrease for PM2·5 and 11% decrease for black carbon), leading to a reduction of around 4200 premature deaths per year (95% CI 2960-5050). However, since 2010, the decreasing trends of fine particles and premature deaths have reversed to increase in the western USA (55% increase in PM2·5, 86% increase in black carbon, and increase of 670 premature deaths [460-810]), while remaining mostly unchanged in the eastern USA. The western USA showed large interannual fluctuations that were attributable to the increasing incidence of wildfires. Furthermore, the black carbon-to-PM2·5 mass ratio increased annually by 2·4% across the USA, mainly due to increasing wildfire emissions in the western USA and more rapid reductions of other components in the eastern USA, suggesting a potential increase in the relative toxicity of PM2·5. 100% of populated areas in the USA have experienced at least one day of PM2·5 pollution exceeding the daily air quality guideline level of 15 μg/m3 during 2000-2020, with 99% experiencing at least 7 days and 85% experiencing at least 30 days. The recent widespread wildfires have greatly increased the daily exposure risks in the western USA, and have also impacted the midwestern USA due to the long-range transport of smoke.

INTERPRETATION

Wildfires have become increasingly intensive and frequent in the western USA, resulting in a significant increase in smoke-related emissions in populated areas. This increase is likely to have contributed to a decline in air quality and an increase in attributable mortality. Reducing fire risk via effective policies besides mitigation of climate warming, such as wildfire prevention and management, forest restoration, and new revenue generation, could substantially improve air quality and public health in the coming decades.

FUNDING

National Aeronautics and Space Administration (NASA) Applied Science programme, NASA MODIS maintenance programme, NASA MAIA satellite mission programme, NASA GMAO core fund, National Oceanic and Atmospheric Administration (NOAA) GEO-XO project, NOAA Atmospheric Chemistry, Carbon Cycle, and Climate (AC4) programme, and NOAA Educational Partnership Program with Minority Serving Institutions.

Route of administration significantly affects particle deposition and cellular recruitment

Lung exposures to dusts, pollutants, and other aerosol particulates are known to be associated with pulmonary diseases such as asthma and Chronic Obstructive Pulmonary Disease. These health impacts are attributed to the ability of aerosol components to induce pulmonary inflammation, which promotes tissue remodeling, including fibrosis, tissue degradation, and smooth muscle proliferation. Consequently, the distribution of these effects can have a significant impact on the physiologic function of the lung. In order to study the impact of distribution of inhaled particulates on lung pathogenesis, we compared the effect of different methods of particle delivery. By comparing intranasal versus aerosol delivery of fluorescent microspheres, we observed strikingly distinct patterns of particle deposition; intranasal delivery provided focused deposition concentrated on larger airways, while aerosol delivery showed unform deposition throughout the lung parenchyma. Recognizing that the impacts of inflammatory cells are contingent upon their recruitment and behavior, we postulate that these variations in distribution patterns can result in significant alterations in biological responses. To elucidate the relevance of these findings in terms of biological representation, we subsequently conducted an investigation into the responses elicited by the administration of endotoxin (bacterial Lipopolysaccharide, or LPS) in a transgenic neutrophil reporter mouse model. As with the microsphere results, patterns of recruited neutrophil inflammatory responses matched the delivery method; that is, despite the active migratory behavior of neutrophils, inflammatory histopathology patterns were either focused on large airways (intranasal administration) or diffusely throughout the parenchyma (aerosol). These results demonstrate the importance of modes of aerosol delivery as different patterns of inflammation and tissue remodeling will have distinct impacts on lung physiology.

Two-sample mendelian randomization analysis investigates ambient fine particulate matter's impact on cardiovascular disease development

PM2.5, a key component of air pollution, significantly threatens public health. Cardiovascular disease is increasingly associated with air pollution, necessitating more research. This study used a meticulous two-sample Mendelian randomization (MR) approach to investigate the potential causal link between elevated PM2.5 levels and 25 types of cardiovascular diseases. Data sourced from the UK Biobank, focusing on individuals of European ancestry, underwent primary analysis using Inverse Variance Weighting. Additional methods such as MR-Egger, weighted median, Simple mode, and Weighted mode provided support. Sensitivity analyses assessed instrument variable heterogeneity, pleiotropy, and potential weak instrument variables. The study revealed a causal link between PM2.5 exposure and higher diagnoses of Atherosclerotic heart disease (primary or secondary, OR [95% CI] 1.0307 [1.0103-1.0516], p-value = 0.003 and OR [95% CI] 1.0179 [1.0028-1.0333], p-value = 0.0202) and Angina pectoris (primary or secondary, OR [95% CI] 1.0303 [1.0160-1.0449], p-value = 3.04e-05 and OR [95% CI] 1.0339 [1.0081-1.0603], p-value = 0.0096). Additionally, PM2.5 exposure increased the likelihood of diagnoses like Other forms of chronic ischaemic heart disease (secondary, OR [95% CI] 1.0193 [1.0042-1.0346], p-value = 0.0121), Essential hypertension (secondary, OR [95% CI] 1.0567 [1.0142-1.1010], p-value = 0.0085), Palpitations (OR [95% CI] 1.0163 [1.0071-1.0257], p-value = 5e-04), and Stroke (OR [95% CI] 1.0208 [1.0020-1.0401], p-value = 0.0301). Rigorous sensitivity analyses confirmed these significant findings' robustness and validity. Our study revealed the causal effect between higher PM2.5 concentrations and increased cardiovascular disease risks. This evidence is vital for policymakers and healthcare providers, urging targeted interventions to reduce PM2.5 levels.

Long-term exposure to ambient fine particulate matter-bound polycyclic aromatic hydrocarbons and cancer mortality: A difference-in-differences approach

The association of ambient fine particulate matter (PM2.5) exposure with cancer mortality was controversial, which may ascribe to the difference in PM2.5 constituents. Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic constituents in PM2.5, which are suspected to account for PM2.5-induced cancer mortality but are yet to be investigated. We aimed to assess the association between long-term exposure to PM2.5-bound PAHs and cancer mortality and estimate the attributable mortality. A difference-in-differences approach was used to investigate the causal effect of long-term exposure to PM2.5-bound PAHs on cancer mortality. We divided Jiangsu province, China into 53 spatial units and summarized the annual number of cancer deaths in each spatial unit during 2016-2020. Annual population-weighted exposure to PM2.5-bound PAHs of each spatial unit was assessed by an inverse distance weighting method. The association between PM2.5-bound PAHs exposures and cancer mortality was evaluated by controlling spatial differences, temporal trends, PM2.5 mass exposures, temperatures, and socioeconomic status. Records of 793,269 cancer deaths were identified among 84.7 million population. Each ln-unit increase of exposure to total benzo[a]pyrene equivalents (∑BaPeq), total carcinogenic PAHs (∑PAH7c), and total PAHs (∑PAHs) was significantly associated with a 3.21%, 3.48%, and 2.64% increased risk of cancer mortality, respectively; the risk increased monotonically at low-level exposures but attenuated or flattened afterward (all p for nonlinearity <0.05). Similar exposure-response associations were identified for specific PAHs except that the associations for both fluoranthene and benzo[a]anthracene were linear. We estimated that exposure to ∑BaPeq, ∑PAH7c, and ∑PAHs contributed to 5.73%, 8.73%, and 7.33% of cancer deaths, respectively. In conclusion, long-term exposure to PM2.5-bound PAHs was associated with an increased risk of cancer mortality and contributed to substantial cancer deaths. Our findings highlight the importance to prevent deaths from cancer by reducing PM2.5-bound PAHs exposures and the necessity to take into consideration specific constituents in particulate pollution management in future.

Effects of Ambient O3 on Respiratory Mortality, Especially the Combined Effects of PM2.5 and O3

BACKGROUND

In China, the increasing concentration of ozone (O3) has emerged as a significant air pollution issue, leading to adverse effects on public health, particularly the respiratory system. Despite the progress made in managing air pollution in China, it is crucial to address the problem of environmental O3 pollution at present.

METHODS

The connection between O3 exposure and respiratory mortality in Shenyang, China, from 2014 to 2018 was analyzed by a time-series generalized additive regression model (GAM) with quasi-Poisson regression. Additionally, the potential combined effects of fine particulate matter (PM2.5) and O3 were investigated using the synergy index (SI).

RESULTS

Our findings indicate that each 10 μg/m3 increase in O3 at lag 2 days was associated with a maximum relative risk (RR) of 1.0150 (95% CI: 1.0098-1.0202) for respiratory mortality in the total population. For individuals aged ≥55 years, unmarried individuals, those engaged in indoor occupations, and those with low educational attainment, each 10 μg/m3 increase in O3 at lag 07 days was linked to RR values of 1.0301 (95% CI: 1.0187-1.0417), 1.0437 (95% CI: 1.0266-1.0610), 1.0317 (95% CI: 1.0186-1.0450), and 1.0346 (95% CI: 1.0222-1.0471), respectively. Importantly, we discovered a synergistic effect of PM2.5 and O3, resulting in an SI of 2.372 on the occurrence of respiratory mortality.

CONCLUSIONS

This study confirmed a positive association between O3 exposure and respiratory mortality. Furthermore, it highlighted the interaction between O3 and PM2.5 in exacerbating respiratory deaths.

Short-term exposure to PM2.5 and 1.5 million deaths: a time-stratified case-crossover analysis in the Mexico City Metropolitan Area

BACKGROUND

Satellite-based PM2.5 predictions are being used to advance exposure science and air-pollution epidemiology in developed countries; including emerging evidence about the impacts of PM2.5 on acute health outcomes beyond the cardiovascular and respiratory systems, and the potential modifying effects from individual-level factors in these associations. Research on these topics is lacking in low and middle income countries. We aimed to explore the association between short-term exposure to PM2.5 with broad-category and cause-specific mortality outcomes in the Mexico City Metropolitan Area (MCMA), and potential effect modification by age, sex, and SES characteristics in such associations.

METHODS

We used a time-stratified case-crossover study design with 1,479,950 non-accidental deaths from the MCMA for the period of 2004-2019. Daily 1 × 1 km PM2.5 (median = 23.4 μg/m3; IQR = 13.6 μg/m3) estimates from our satellite-based regional model were employed for exposure assessment at the sub-municipality level. Associations between PM2.5 with broad-category (organ-system) and cause-specific mortality outcomes were estimated with distributed lag conditional logistic models. We also fit models stratifying by potential individual-level effect modifiers including; age, sex, and individual SES-related characteristics namely: education, health insurance coverage, and job categories. Odds ratios were converted into percent increase for ease of interpretation.

RESULTS

PM2.5 exposure was associated with broad-category mortality outcomes, including all non-accidental, cardiovascular, cerebrovascular, respiratory, and digestive mortality. A 10-μg/m3 PM2.5 higher cumulative exposure over one week (lag06) was associated with higher cause-specific mortality outcomes including hypertensive disease [2.28% (95%CI: 0.26%-4.33%)], acute ischemic heart disease [1.61% (95%CI: 0.59%-2.64%)], other forms of heart disease [2.39% (95%CI: -0.35%-5.20%)], hemorrhagic stroke [3.63% (95%CI: 0.79%-6.55%)], influenza and pneumonia [4.91% (95%CI: 2.84%-7.02%)], chronic respiratory disease [2.49% (95%CI: 0.71%-4.31%)], diseases of the liver [1.85% (95%CI: 0.31%-3.41%)], and renal failure [3.48% (95%CI: 0.79%-6.24%)]. No differences in effect size of associations were observed between age, sex and SES strata.

CONCLUSIONS

Exposure to PM2.5 was associated with non-accidental, broad-category and cause-specific mortality outcomes beyond the cardiovascular and respiratory systems, including specific death-causes from the digestive and genitourinary systems, with no indication of effect modification by individual-level characteristics.

Exposure to low-level ambient air pollution and the relationship with lung and bladder cancer in older men, in Perth, Western Australia

BACKGROUND

Air pollution is a cause of lung cancer and is associated with bladder cancer. However, the relationship between air pollution and these cancers in regions of low pollution is unclear. We investigated associations between fine particulate matter (PM2.5), nitrogen dioxide, and black carbon (BC), and both these cancers in a low-pollution city.

METHODS

A cohort of 11,679 men ≥65 years old in Perth (Western Australia) were followed from 1996-1999 until 2018. Pollutant concentrations, as a time-varying variable, were estimated at participants' residential addresses using land use regression models. Incident lung and bladder cancer were identified through the Western Australian Cancer Registry. Risks were estimated using Cox proportional-hazard models (age as the timescale), adjusting for smoking, socioeconomic status, and co-pollutants.

RESULTS

Lung cancer was associated with PM2.5 and BC in the adjusted single-pollutant models. A weak positive association was observed between ambient air pollution and squamous cell lung carcinoma but not lung adenocarcinoma. Positive associations were observed with bladder cancer, although these were not statistically significant. Associations were attenuated in two-pollutant models.

CONCLUSION

Low-level ambient air pollution is associated with lung, and possibly bladder, cancer among older men, suggesting there is no known safe level for air pollution as a carcinogen.

Sex Associations Between Air Pollution and Estimated Atherosclerotic Cardiovascular Disease Risk Determination

Objective: The purpose of this study was to investigate the sex correlations of particulate matters (PM2.5, PM10, PM2.5-10), NO2 and NOx with ASCVD risk in the UK Biobank population. Methods: Among 285,045 participants, pollutants were assessed and correlations between ASCVD risk were stratified by sex and estimated using multiple linear and logistic regressions adjusted for length of time at residence, education, income, physical activity, Townsend deprivation, alcohol, smocking pack years, BMI and rural/urban zone. Results: Males presented higher ASCVD risk than females (8.63% vs. 2.65%, p < 0.001). In males PM2.5, PM10, NO2, and NOx each were associated with an increased ASCVD risk >7.5% in the adjusted logistic models, with ORs [95% CI] for a 10 μg/m3 increase were 2.17 [1.87-2.52], 1.15 [1.06-1.24], 1.06 [1.04-1.08] and 1.05 [1.04-1.06], respectively. In females, the ORs for a 10 μg/m3 increase were 1.55 [1.19-2.05], 1.22 [1.06-1.42], 1.07 [1.03-1.10], and 1.04 [1.02-1.05], respectively. No association was observed in both sexes between ASCVD risk and PM2.5-10. Conclusion: Our findings may suggest the possible actions of air pollutants on ASCVD risk.

Household conditions, COVID-19, and equity: Insight from two nationally representative surveys

Background

With people across the United States spending increased time at home since the emergence of COVID-19, housing characteristics may have an even greater impact on health. Therefore, we assessed associations between household conditions and COVID-19 experiences.

Methods

We used data from two nationally representative surveys: the Tufts Equity Study (TES; n = 1449 in 2021; n = 1831 in 2022) and the Household Pulse Survey (HPS; n = 147,380 in 2021; n = 62,826 in 2022). In the TES, housing conditions were characterized by heating/cooling methods; smoking inside the home; visible water damage/mold; age of housing unit; and self-reported concern about various environmental factors. In TES and HPS, household size was assessed. Accounting for sampling weights, we examined associations between each housing exposure and COVID-19 outcomes (diagnosis, vaccination) using separate logistic regression models with covariates selected based on an evidence-based directed acyclic graph.

Results

Having had COVID-19 was more likely among people who reported poor physical housing condition (odds ratio [OR] = 2.32; 95% confidence interval [CI] = 1.17-4.59; 2021), visible water damage or mold/musty smells (OR = 1.50; 95% CI = 1.10-2.03; 2022), and larger household size (5+ versus 1-2 people; OR = 1.53, 95% CI = 1.34-1.75, HPS 2022). COVID-19 vaccination was less likely among participants who reported smoke exposure inside the home (OR = 0.53; 95% CI = 0.31-0.90; 2022), poor water quality (OR = 0.42; 95% CI = 0.21-0.85; 2021), noise from industrial activity/construction (OR = 0.44; 95% CI = 0.19-0.99; 2022), and larger household size (OR = 0.57; 95% CI = 0.46-0.71; HPS 2022). Vaccination was also positively associated with poor indoor air quality (OR = 1.96; 95% CI = 1.02-3.72; 2022) and poor physical housing condition (OR = 2.27; 95% CI = 1.01-5.13; 2022). Certain heating/cooling sources were associated with COVID-19 outcomes.

Conclusions

Our study found poor housing conditions associated with increased COVID-19 burden, which may be driven by systemic disparities in housing, healthcare, and financial access to resources during the COVID-19 pandemic.

Spatiotemporal variations and mechanism of PM2.5 pollution in urban area: The case of Guiyang, Guizhou, China

PM_2.5 has been a hot concern in the recent decade. Many studies have focused on metropolises or those areas with poor air quality, but the PM_2.5 of more widespread areas is less considered. Considering the challenges of rapid economic growth and environmental problems against a developing region, we took Guiyang as a study case to assess the spatiotemporal variations and mechanism of PM2.5 pollution in an urban area from 2000 to 2020 in an extended sense. Based on PM_2.5 concentration data from 14 monitoring points in Guiyang, spatiotemporal variations and formation mechanism were assessed using wavelet, moving maximal information coefficients, and spatial correlation analysis. The urban Nighttime light data was selected to evaluate the impacts of socioeconomic factors on PM2.5 concentration using spatial correlation analysis. Further, wavelet and statistical analysis were adopted to analyze multi-dimensional temporal variations of PM_2.5 hourly concentration and the relationship with pressure, temperature, vapor pressure, relative humidity, wind, and visibility. The PM_2.5 hourly concentration was obtained from the monitoring points in downtown Guiyang according to data continuity and availability. PM_2.5 had different temporal variations at daily, monthly, seasonal, and annual levels, and interannual variation was the most obvious. The temperature was the main factor leading to the interannual temporal variation of PM_2.5. Wind and pressure were more significant for the responses of a shorter period variation with -0.76 and -0.80 of the minimum of correlation coefficient, respectively. Meanwhile, human activities significantly influenced spatiotemporal variations of PM_2.5. A spatial correlation analysis between PM2.5 and the related influencing factors from 2000 to 2018 was implemented based on a geographic information system. Besides, the landcovers within a buffer zone with a radius of 1 km on 14 monitoring points were visually interpreted to analyze the relationship between PM_2.5 and landcovers. Moreover, multivariate wavelet coherence analysis revealed the PM2.5 interaction among monitoring points. The PM_2.5 concentration in Guiyang dropped from 49 μg/m³ in 2012 to about 27 μg/m³ in 2018, and the air quality greatly improved. As in most cities, Guiyang has a significant PM_2.5 pollution island effect, with traffic and building land density contributing to higher PM_2.5 concentrations. There were some typical nonlinear spatiotemporal variations between PM_2.5 and its influencing factors, and these variations varied with the selected scale.

Source apportionment of PM10 and health risk assessment related in a narrow tropical valley. Study case: Metropolitan area of Aburrá Valley (Colombia)

This study investigates spatio-temporal variations of PM10 mass concentrations and associated metal(oid)s, δ13C carbon isotope ratios, polycyclic aromatic hydrocarbons (PAHs), total organic carbon (TOC) and equivalent black carbon (eBC) concentrations over a half year period (from March 2017 to October 2017) in two residential areas of Medellín (MED-1 and MED-2) and Itagüí municipality (ITA-1 and ITA-2) at a tropical narrow valley (Aburrá Valley, Colombia), where few data are available. A total of 104 samples were analysed by using validated analytical methodologies, providing valuable data for PM10 chemical characterisation. Metal(oid)s concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion, and PAHs concentrations were measured by Gas Chromatography-Mass Spectrometry (GC-MS) after Pressurised Hot Water Extraction (PHWE) and Membrane Assisted Solvent Extraction (MASE). Mean PM10 mass concentration ranged from 37.0 µg m-3 to 45.7 µg m-3 in ITA-2 and MED-2 sites, respectively. Al, Ca, Mg and Na (from 6249 ng m-3 for Mg at MED-1 site to 10,506 ng m-3 for Ca at MED-2 site) were the major elements in PM10 samples, whilst As, Be, Bi, Co, Cs, Li, Ni, Sb, Se, Tl and V were found at trace levels (< 5.4 ng m-3). Benzo[g,h,i] perylene (BghiP), benzo[b + j]fluoranthene (BbjF) and indene(1,2,3-c,d)pyrene (IcdP) were the most profuse PAHs in PM10 samples, with average concentrations of 0.82-0.86, 0.60-0.78 and 0.47-0.58 ng m-3, respectively. Results observed in the four sampling sites showed a similar dispersion pattern of pollutants, with temporal fluctuations which seems to be associated to the meteorology of the valley. A PM source apportionment study were carried out by using the positive matrix factorization (PMF) model, pointing to re-suspended dust, combustion processes, quarry activity and secondary aerosols as PM10 sources in the study area. Among them, combustion was the major PM10 contribution (accounting from 32.1 to 32.9% in ITA-1 and ITA-2, respectively), followed by secondary aerosols (accounting for 13.2% and 23.3% ITA-1 and MED-1, respectively). Finally, a moderate carcinogenic risk was observed for PM10-bound PAHs exposure via inhalation, whereas significant carcinogenic risk was estimated for carcinogenic metal(oid)s exposure in the area during the sampling period.

Long-term exposure to fine particulate matter and site-specific cancer mortality: A difference-in-differences analysis in Jiangsu province, China

BACKGROUND

Accumulating studies have reported that chronic exposure to ambient fine particulate matter (PM_2.5) can lead to adverse effects on lung cancer mortality; however, such chronic effects are less clear for mortality from other site-specific cancers.

OBJECTIVE

To explore the causal effect of long-term PM_2.5 exposure on mortality from all-site and a variety of site-specific cancers in Jiangsu province, China during 2015-2020 using a difference-in-differences analysis.

METHODS

For each of 53 county-based spatial units in Jiangsu province, we calculated annual death counts for all-site cancer and 23 site-specific cancers. Using a validated high-resolution PM_2.5 grid dataset, long-term PM_2.5 exposure of a spatial unit within a given year was evaluated as the average of population-weighted annual concentrations during recent 10 years. Conditional Poisson regression models were employed to evaluate exposure-response associations adjusting for spatial and temporal variables, seasonal temperatures, relative humidity, and gross domestic product (GDP).

RESULTS

During the study period, we identified 947,337 adult cancer deaths in Jiangsu province. Each 1 μg/m³ increment in PM_2.5 exposure was significantly associated with a 2.7% increase in the risk of all-site cancer mortality. PM_2.5-mortality associations were also observed in cancer of lip, oral cavity and pharynx, stomach, colorectum, pancreas, lung, bone and joints, ovary, prostate, and lymphoma (all adjusted P < 0.05), with the relative risks ranging from 1.028 (95% confidence interval [CI]: 1.011, 1.046) for stomach cancer to 1.201 (95% CI: 1.120, 1.308) for bone and joints cancers. Exposure-response curves showed that these associations were close to linearity, though most of them had increasing slopes at high exposure levels. Overall, women and subjects in low GDP regions were more vulnerable to PM_2.5 exposures.

CONCLUSIONS

Long-term exposure to ambient PM_2.5 contributes to a higher risk of mortality from multiple site-specific cancers.

The Impact of Long-Term Air Pollution Exposure on Type 1 Diabetes Mellitus-Related Mortality among U.S. Medicare Beneficiaries

BACKGROUND

Little of the previous literature has investigated associations between air pollution exposure and type 1 diabetes mellitus (T1DM)-related mortality, despite a well-established link between air pollution exposure and other autoimmune diseases.

METHODS

In a cohort of 53 million Medicare beneficiaries living across the conterminous United States, we used Cox proportional hazard models to assess the association of long-term PM_2.5 and NO₂ exposures on T1DM-related mortality from 2000 to 2008. Models included strata for age, sex, race, and ZIP code and controlled for neighborhood socioeconomic status (SES); we additionally investigated associations in two-pollutant models, and whether associations were modified by participant demographics.

RESULTS

A 10 μg/m³ increase in 12-month average PM_2.5 (HR: 1.183; 95% CI: 1.037-1.349) and a 10 ppb increase in NO₂ (HR: 1.248; 95% CI: 1.089-1.431) was associated with an increased risk of T1DM-related mortality in age-, sex-, race-, ZIP code-, and SES-adjusted models. Associations for both pollutants were consistently stronger among Black (PM_2.5: HR:1.877, 95% CI: 1.386-2.542; NO₂: HR: 1.586, 95% CI: 1.258-2.001) and female (PM_2.5: HR:1.297, 95% CI: 1.101-1.529; NO₂: HR: 1.390, 95% CI: 1.187-1.627) beneficiaries.

CONCLUSIONS

Long-term NO₂ and, to a lesser extent, PM_2.5 exposure is associated with statistically significant elevations in T1DM-related mortality risk.

Evaluating Race in Air Pollution and Health Research: Race, PM2.5 Air Pollution Exposure, and Mortality as a Case Study

PURPOSE OF REVIEW

Racial inequities in air pollution exposure have been documented. There is also interest in documenting the modifying role of race in the link between air pollution and health. However, the empirical literature in this area has yielded mixed results with potentially unclear policy implications. We critically evaluate recent empirical papers on the interactive association between race and air pollution exposure on adult mortality in the USA as a case study of the race, pollution, and health literature. Specifically, we evaluate these studies for the conceptualization and discussion of race and the use of race variables that may contribute to the ambiguous results and policy implications both in this specific literature and in the broader literature.

RECENT FINDINGS

We evaluate ten empirical studies from 2016 to 2022 on the modifying role of race in the association between short- and long-term PM2.5 exposure and specific types of adult mortality (all cause, non-accidental, and heart or cardiovascular diseases) in the USA. In addition to comparing and contrasting the empirical results, we focus our review on the conceptualization, measurement, modeling, and discussion of race and the race variables. Overall, the results indicate no consistent role of race in the association between PM2.5 exposure and mortality. Moreover, conceptualization and discussion of race was often brief and incomplete, even when the empirical results were unexpected or counterintuitive. To build on recent discussions in the epidemiology and environmental epidemiology literature more specifically, we provide a detailed discussion of the meaning of race, the race variables, and the cultural and structural racism that some argue are proxied by race variables. We use theoretical scholarship from the humanities and social sciences along with empirical work from the environmental literature to provide recommendations for future research that can provide an evidence base to inform both social and environmental policy.

The association between long-term ambient fine particulate exposure and the mortality among adult patients initiating dialysis: A retrospective population-based cohort study in Taiwan

Fine particulate matter (PM_2.5) has been reported to be associated with increased risk of chronic kidney disease (CKD) and progression to end-stage renal disease (ESRD). However, studies on whether long-term exposure to PM_2.5 negatively impacts the survival of patients with ESRD are very limited. To conduct this study, we linked Taiwan Air Quality-Monitoring Database (TAQMD) and the National Health Insurance Research Database (NHIRD) by zip-code. A retrospective population-based cohort of 34,088 adult patients initiating dialysis over six months was formed. Cox proportional regression models were used to estimate the risk of mortality in dialysis patients per 10-μg/m³ increase of PM_2.5 and by PM_2.5 levels divided into quintiles. Restricted cubic spline analysis was performed to delineate the concentration-response relationship between PM_2.5 and mortality. The adjusted hazard ratio (aHR) per 10-μg/m³ increase of PM_2.5 for mortality was 1.11 (95% confidence interval [CI] = 1.08-1.13). When analyzing PM_2.5 exposure divided into quintiles, patients with mean PM_2.5 exposure over 29.33 μg/m³, including level III (aHR 1.00, 95% CI = 0.94-1.07), level IV (aHR 1.09; 95% CI = 1.03-1.16), and level V (HR 1.11; 95% CI = 1.05-1.19), were at stepwise higher risks of mortality compared with level I. Spline analysis showed a non-linear concentration-response function between PM_2.5 and mortality, with the lowest mortality aHR identified at a mean PM_2.5 of 26 μg/m³, followed by a concentration interval with a gradual increase of aHR, and finally a steep rise of mortality risk when mean PM_2.5 exceeded 37 μg/m³. Individuals with older age, those were male, with selected comorbidities, and with low socioeconomic status (SES) were at higher mortality risk. Male and non-diabetics participants were more sensitive to the effect of a 10-μg/m³ of PM_2.5 increase on mortality than their counterparts. In conclusion, long-term exposure to PM_2.5 exceeding a threshold was observed to be associated with increased risk of mortality among dialysis patients.

"When people see me, they know me; they trust what I say": characterizing the role of trusted sources for smoke risk communication in the Okanogan River Airshed Emphasis Area

INTRODUCTION

As wildfire smoke events increase in intensity and frequency in the Pacific Northwest, there is a growing need for effective communication on the health risks of smoke exposure. Delivery through a trusted source or intermediary has been shown to improve reception of risk communication messages. This is especially salient in rural and tribal communities who may be hesitant to trust information from state and federal agency sources. This study aims to identify and characterize trusted sources for smoke risk information in the Okanogan River Airshed Emphasis Area (ORAEA), a rural region of North Central Washington state that is heavily impacted by smoke from wildfires and prescribed fire.

METHODS

The research team conducted a qualitative study using data collected through key informant interviews and focus groups to assess the role of various sources and intermediaries in disseminating smoke risk information. We used a consensual coding approach in NVivo Qualitative Analysis Software to sort data into preliminary categories, which were grouped into themes using a thematic analysis approach. We used member checking and iterative feedback processes with local project partners throughout the project to ensure credibility of results.

RESULTS

Through the analysis, we identified three themes characterizing trusted sources for smoke risk communication in the ORAEA. These themes were: (1) local and tribal sources of information are perceived as more trustworthy than state and federal government sources, (2) trustworthiness is determined by an evaluation of multiple factors, in particular, perceived credibility, quality of information, and relationship with the source, and (3) conservative political ideology and perceived parallels with COVID-19 communication influence perception of trust. Within each theme, we identified several sub-themes, which contributed additional nuance to our analysis.

CONCLUSION

This study provides insights into which sources of information are trusted by rural and tribal community members in the ORAEA and why. Results from our study emphasize the importance of relationships and collaboration with local and tribal partners in smoke risk communication. In this paper, we discuss implications for state and federal agency practitioners and present recommendations for how to work with local and tribal partners on smoke risk communication.

Etiology of lung cancer: Evidence from epidemiologic studies

Lung cancer is one of the leading causes of cancer incidence and mortality worldwide. While smoking, radon, air pollution, as well as occupational exposure to asbestos, diesel fumes, arsenic, beryllium, cadmium, chromium, nickel, and silica are well-established risk factors, many lung cancer cases cannot be explained by these known risk factors. Over the last two decades the incidence of adenocarcinoma has risen, and it now surpasses squamous cell carcinoma as the most common histologic subtype. This increase warrants new efforts to identify additional risk factors for specific lung cancer subtypes as well as a comprehensive review of current evidence from epidemiologic studies to inform future studies. Given the myriad exposures individuals experience in real-world settings, it is essential to investigate mixture effects from complex exposures and gene-environment interactions in relation to lung cancer and its subtypes.

Traffic-related Air Pollution and Lung Cancer Incidence: The California Multiethnic Cohort Study

Rationale: Although the contribution of air pollution to lung cancer risk is well characterized, few studies have been conducted in racially, ethnically, and socioeconomically diverse populations. Objectives: To examine the association between traffic-related air pollution and risk of lung cancer in a racially, ethnically, and socioeconomically diverse cohort. Methods: Among 97,288 California participants of the Multiethnic Cohort Study, we used Cox proportional hazards regression to examine associations between time-varying traffic-related air pollutants (gaseous and particulate matter pollutants and regional benzene) and lung cancer risk (n = 2,796 cases; average follow-up = 17 yr), adjusting for demographics, lifetime smoking, occupation, neighborhood socioeconomic status (nSES), and lifestyle factors. Subgroup analyses were conducted for race, ethnicity, nSES, and other factors. Measurements and Main Results: Among all participants, lung cancer risk was positively associated with nitrogen oxide (hazard ratio [HR], 1.15 per 50 ppb; 95% confidence interval [CI], 0.99-1.33), nitrogen dioxide (HR, 1.12 per 20 ppb; 95% CI, 0.95-1.32), fine particulate matter with aerodynamic diameter <2.5 μm (HR, 1.20 per 10 μg/m3; 95% CI, 1.01-1.43), carbon monoxide (HR, 1.29 per 1,000 ppb; 95% CI, 0.99-1.67), and regional benzene (HR, 1.17 per 1 ppb; 95% CI, 1.02-1.34) exposures. These patterns of associations were driven by associations among African American and Latino American groups. There was no formal evidence for heterogeneity of effects by nSES (P heterogeneity > 0.21), although participants residing in low-SES neighborhoods had increased lung cancer risk associated with nitrogen oxides, and no association was observed among those in high-SES neighborhoods. Conclusions: These findings in a large multiethnic population reflect an association between lung cancer and the mixture of traffic-related air pollution and not a particular individual pollutant. They are consistent with the adverse effects of air pollution that have been described in less racially, ethnically, and socioeconomically diverse populations. Our results also suggest an increased risk of lung cancer among those residing in low-SES neighborhoods.

Transcriptome analysis identifies IL24 as an autophagy modulator in PM2.5 caused lung dysfunction

BACKGROUND

Evidence suggests that exposure to PM_2.5 increased hospitalization and mortality rates of respiratory diseases. However, the potential biomarkers and targets associated with PM_2.5-induced lung dysfunction are not fully discovered.

METHODS

Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and HALLMARK enrichment analysis of the RNA-seq data (Beas-2B cells treated with PM_2.5) were applied. Gene set enrichment analysis (GSEA) was performed to identify the biological processes correlated with autophagy. Three gene expression profile datasets (GSE158954, GSE155616 and GSE182199) were downloaded from the Gene Expression Omnibus (GEO) database to identify the potential targets. PM_2.5-exposed mice were constructed. Real-time qPCR, siRNA transfection, western blot, immunofluorescence, and pathological staining were applied for validation both in vitro and in vivo studies.

RESULTS

GO, KEGG and HALLMARK enrichment based on RNA-seq data showed that the differentially expressed genes (DEGs) were associated with autophagy like lysosome and macroautophagy. GSEA analysis revealed that PM_2.5 was positively correlated with autophagy-related biological processes compared with control group. Venn diagrams identified IL24 was upregulated in our data as well as in these three datasets (GSE158954, GSE155616 and GSE182199) after PM_2.5 exposure. Consistent with the analysis, activation of autophagy by PM_2.5 was validated in vivo and in vitro. In PM_2.5-exposed mice, lung pathological changes were observed, including airway inflammation and mucus secretion. The mRNA and protein levels of the key gene, IL24, were significantly increased. Moreover, Bafilomycin A1, the inhibitor of autophagy, inhibited the autophagy and ameliorated lung injury induced by PM2.5. Furthermore, downregulation of IL24 decreased autophagy activity. Meanwhile, IL24 was regulated by mTOR signaling.

CONCLUSIONS

In summary, we discovered a potential relationship between IL24 and autophagy during PM_2.5 exposure. IL24 might be a novel potential biomarker or therapeutic target in PM_2.5 caused lung dysfunction through regulation of autophagy.

Estimating ground-level PM2.5 over Bangkok Metropolitan Region in Thailand using aerosol optical depth retrieved by MODIS

A number of previous studies have shown that statistical model with a combination of satellite-derived aerosol optical depth (AOD) and PM_2.5 measured by the monitoring stations could be applied to predict spatial ground-level PM_2.5 concentration, but few studies have been conducted in Thailand. This study aimed to estimate ground-level PM_2.5 over the Bangkok Metropolitan Region in 2020 using linear regression model that incorporates the Moderate Resolution Imaging Spectroradiometer (MODIS) AOD measurements and other air pollutants, as well as various meteorological factors and greenness indicators into the model. The 12-fold cross-validation technique was used to examine the accuracy of model performance. The annual mean (standard deviation) concentration of observed PM_2.5 was 22.37 (± 12.55) µg/m³ and the mean (standard deviation) of PM_2.5 during summer, winter, and rainy season was 18.36 (± 7.14) µg/m³, 33.60 (± 14.48) µg/m³, and 15.30 (± 4.78) µg/m³, respectively. The cross-validation yielded R ² of 0.48, 0.55, 0.21, and 0.52 with the average of predicted PM_2.5 concentration of 22.25 (± 9.97) µg/m³, 21.68 (± 9.14) µg/m³, 29.43 (± 9.45) µg/m³, and 15.74 (± 5.68) µg/m³ for the year round, summer, winter, and rainy season, respectively. We also observed that integrating NO₂ and O₃ into the regression model improved the prediction accuracy significantly for a year round, summer, winter, and rainy season over the Bangkok Metropolitan Region. In conclusion, estimating ground-level PM_2.5 concentration from the MODIS AOD measurement using linear regression model provided the satisfactory model performance when incorporating many possible predictor variables that would affect the association between MODIS AOD and PM_2.5 concentration.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11869-022-01238-4.

The links of fine airborne particulate matter exposure to occurrence of cardiovascular and metabolic diseases in Michigan, USA

Air pollutants, particularly airborne particulate matter with aerodynamic diameter < 2.5μm (PM2.5), have been linked to the increase in mortality and morbidity associated with cardiovascular and metabolic diseases. In this study, we investigated the dose-risk relationships between PM2.5 concentrations and occurrences of cardiovascular and metabolic diseases as well as the confounding socioeconomic factors in Michigan, USA, where PM2.5 levels are generally considered acceptable. Multivariate linear regression analyses were performed to investigate the relationship between health outcome and annual ground-level PM2.5 concentrations of 82 counties in Michigan. The analyses revelated significant linear dose-response associations between PM2.5 concentrations and cardiovascular disease (CVD) hospitalization. A 10 μg/m3 increase in PM2.5 exposure was found to be associated with a 3.0% increase in total CVD, 0.45% increase in Stroke, and a 0.3% increase in Hypertension hospitalization rates in Medicare beneficiaries. While the hospitalization rates of Total Stroke, Hemorrhagic Stroke, and Hypertension in urbanized counties were significantly higher than those of rural counties, the death rates of coronary heart disease and ischemic stroke in urbanized counties were significantly lower than those of rural counties. These results were correlated with the facts that PM2.5 levels in urbanized counties were significantly higher than that in rural counties and that the percentage of the population with health insurance and the median household income in rural counties were significantly lower. While obesity prevalence showed evidence of a weak positive correlation (ρ = 0.20, p-value = 0.078) with PM2.5 levels, there was no significant dose-response association between county diabetes prevalence rates and PM2.5 exposure in Michigan. In summary, this study revealed strong dose-response associations between PM2.5 concentrations and CVD incidence in Michigan, USA. The socioeconomic factors, such as access to healthcare resources and median household income, represent important confounding factors that could override the impact of PM2.5 exposure on CVD mortality.

N-acetylcysteine alleviates fine particulate matter (PM2.5)-induced lung injury by attenuation of ROS-mediated recruitment of neutrophils and Ly6Chigh monocytes and lung inflammation

BACKGROUND

Exposure to particulate matter (PM) may contribute to lung inflammation and injury. The therapeutic effect of N-acetylcysteine (NAC), a well-known antioxidant, with regards to the prevention and treatment of fine PM (PM2.5)-induced lung injury is poorly understood. This study aimed to determine the effect of PM2.5 on the recruitment of neutrophils and Ly6C^high monocytes into lung alveoli and the production of proinflammatory proteins by stimulating the generation of reactive oxygen species (ROS), and to investigate the therapeutic effect of NAC on PM2.5-induced lung injury.

METHODS

C57BL/6 mice were exposed to a single administration of PM2.5 (200 μg/100 μl/mouse) or phosphate-buffered saline (control) via intratracheal instillation. The mice were injected intratracheally via a microsprayer aerosolizer with NAC (20 or 40 mg/kg) 1 h before PM2.5 instillation and 24 h after PM2.5 instillation. Total protein, VEGF, IL-6, and TNF-α in bronchoalveolar lavage fluid (BALF) were measured. Oxidative stress was evaluated by determining levels of malondialdehyde (MDA) and nitrite in BALF. Flow cytometric analysis was used to identify and quantify neutrophils and Ly6C^high and Ly6C_low monocyte subsets.

RESULTS

Neutrophil count, total protein, and VEGF content in BALF significantly increased after PM2.5 exposure and reached the highest level on day 2. Increased levels of TNF-alpha, IL-6, nitrite, and MDA in BALF were also noted. Flow cytometric analysis showed increased recruitment of neutrophils and Ly6C^high, but not Ly6C^low monocytes, into lung alveoli. Treatment with NAC via the intratracheal spray significantly attenuated the recruitment of neutrophils and Ly6C^high monocytes into lung alveoli in PM2.5-treated mice in a dose-dependent manner. Furthermore, NAC significantly attenuated the production of total protein, VEGF, nitrite, and MDA in the mice with PM2.5-induced lung injury in a dose-dependent manner.

CONCLUSION

PM2.5-induced lung injury caused by the generation of oxidative stress led to the recruitment of neutrophils and Ly6C^high monocytes, and production of inflammatory proteins. NAC treatment alleviated PM2.5-induced lung injury by attenuating the ROS-mediated recruitment of neutrophils and Ly6C^high monocytes and lung inflammation.

Health and Clinical Impacts of Air Pollution and Linkages with Climate Change

Air Pollution Impacts and Climate Change LinksAs part of the NEJM Group series on climate change, Keswani and colleagues review the linkages between climate change and air pollution and suggest strategies that clinicians may use to mitigate the adverse health impacts of air pollution.

Long-term PM2.5 exposure and sepsis mortality in a US medicare cohort

Background

Risk factors contributing to sepsis-related mortality include clinical conditions such as cardiovascular disease, chronic lung disease, and diabetes, all of which have also been shown to be associated with air pollution exposure. However, the impact of chronic exposure to air pollution on sepsis-related mortality has been little studied. 

Methods

In a cohort of 53 million Medicare beneficiaries (228,439 sepsis-related deaths) living across the conterminous United States between 2000 and 2008, we examined the association of long-term PM_2.5 exposure and sepsis-related mortality. For each Medicare beneficiary (ages 65–120), we estimated the 12-month moving average PM_2.5 concentration for the 12 month before death, for their ZIP code of residence using well validated GIS-based spatio-temporal models. Deaths were categorized as sepsis-related if they have ICD-10 codes for bacterial or other sepsis. We used Cox proportional hazard models to assess the association of long-term PM_2.5 exposure on sepsis-related mortality. Models included strata for age, sex, race, and ZIP code and controlled for neighborhood socio-economic status (SES). We also evaluated confounding through adjustment of neighborhood behavioral covariates.

Results

A 10 μg/m³ increase in 12-month moving average PM_2.5 was associated with a 9.1% increased risk of sepsis mortality (95% CI: 3.6–14.9) in models adjusted for age, sex, race, ZIP code, and SES. HRs for PM_2.5 were higher and statistically significant for older (> 75), Black, and urban beneficiaries. In stratified analyses, null associations were found for younger beneficiaries (65–75), beneficiaries who lived in non-urban ZIP codes, and those residing in low-SES urban ZIP codes.

Conclusions

Long-term PM_2.5 exposure is associated with elevated risks of sepsis-related mortality.

Mortality Attributable to Long-Term Exposure to Ambient Fine Particulate Matter: Insights from the Epidemiologic Evidence for Understudied Locations

Epidemiologic cohort studies have consistently demonstrated that long-term exposure to ambient fine particles (PM_2.5) is associated with mortality. Nevertheless, extrapolating results to understudied locations may involve considerable uncertainty. To explore this issue, this review discusses the evidence for (i) the associated risk of mortality, (ii) the shape of the concentration-response function, (iii) a causal interpretation, and (iv) how the source mix/composition of PM_2.5 and population characteristics may alter the effect. The accumulated evidence suggests the following: (i) In the United States, the change in all-cause mortality risk per μg/m³ is about 0.8%. (ii) The concentration-response function appears nonlinear. (iii) Causation is overwhelmingly supported. (iv) Fossil fuel combustion-related sources are likely more toxic than others, and age, race, and income may modify the effect. To illustrate the use of our findings in support of a risk assessment in an understudied setting, we consider Kuwait. However, given the complexity of this relationship and the heterogeneity in reported effects, it is unreasonable to think that, in such circumstances, point estimates can be meaningful. Consequently, quantitative probabilistic estimates, which cannot be derived objectively, become essential. Formally elicited expert judgment can provide such estimates, and this review provides the evidence to support an elicitation.

Low-Concentration Air Pollution and Mortality in American Older Adults: A National Cohort Analysis (2001-2017)

Mounting epidemiological evidence has documented the associations between long-term exposure to multiple air pollutants and increased mortality. There is a pressing need to determine whether risks persist at low concentrations including below current national standards. Air pollution levels have decreased in the United States, and better understanding of the health effects of low-level air pollution is essential for the amendment of National Ambient Air Quality Standards (NAAQS). A nationwide, population-based, open cohort study was conducted to estimate the association between long-term exposure to low-level PM_2.5, NO₂, O₃, and all-cause mortality. The study population included all Medicare enrollees (ages 65 years or older) in the contiguous U.S. from 2001 to 2017. We further defined three low-exposure subcohorts comprised of Medicare enrollees who were always exposed to low-level PM_2.5 (annual mean ≤12-μg/m³), NO₂ (annual mean ≤53-ppb), and O₃ (warm-season mean ≤50-ppb), respectively, over the study period. Of the 68.7-million Medicare enrollees, 33.1% (22.8-million, mean age 75.9 years), 93.8% (64.5-million, mean age 76.2 years), and 65.0% (44.7-million, mean age 75.6 years) were always exposed to low-level annual PM_2.5, annual NO₂, and warm-season O₃ over the study period, respectively. Among the low-exposure cohorts, a 10-μg/m³ increase in PM_2.5, 10-ppb increase in NO₂, and 10-ppb increase in warm-season O₃, were, respectively, associated with an increase in mortality rate ranging between 10 and 13%, 2 and 4%, and 12 and 14% in single-pollutant models, and between 6 and 8%, 1 and 3%, and 9 and 11% in tripollutant models, using three statistical approaches. There was strong evidence of linearity in concentration-response relationships for PM_2.5 and NO₂ at levels below the current NAAQS, suggesting that no safe threshold exists for health-harmful pollution levels. For O₃, the concentration-response relationship shows an increasingly positive association at levels above 40-ppb. In conclusion, exposure to low levels of PM_2.5, NO₂, and warm-season O₃ was associated with an increased risk of all-cause mortality.

Long-term exposure to air pollution and mortality in a Danish nationwide administrative cohort study: Beyond mortality from cardiopulmonary disease and lung cancer

BACKGROUND

The association between long-term exposure to air pollution and mortality from cardiorespiratory diseases is well established, yet the evidence for other diseases remains limited.

OBJECTIVES

To examine the associations of long-term exposure to air pollution with mortality from diabetes, dementia, psychiatric disorders, chronic kidney disease (CKD), asthma, acute lower respiratory infection (ALRI), as well as mortality from all-natural and cardiorespiratory causes in the Danish nationwide administrative cohort.

METHODS

We followed all residents aged ≥ 30 years (3,083,227) in Denmark from 1 January 2000 until 31 December 2017. Annual mean concentrations of fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), black carbon (BC), and ozone (warm season) were estimated using European-wide hybrid land-use regression models (100 m × 100 m) and assigned to baseline residential addresses. We used Cox proportional hazard models to evaluate the association between air pollution and mortality, accounting for demographic and socioeconomic factors. We additionally applied indirect adjustment for smoking and body mass index (BMI).

RESULTS

During 47,023,454 person-years of follow-up, 803,881 people died from natural causes. Long-term exposure to PM_2.5 (mean: 12.4 µg/m³), NO₂ (20.3 µg/m³), and/or BC (1.0 × 10^-5/m) was statistically significantly associated with all studied mortality outcomes except CKD. A 5 µg/m³ increase in PM_2.5 was associated with higher mortality from all-natural causes (hazard ratio 1.11; 95% confidence interval 1.09-1.13), cardiovascular disease (1.09; 1.07-1.12), respiratory disease (1.11; 1.07-1.15), lung cancer (1.19; 1.15-1.24), diabetes (1.10; 1.04-1.16), dementia (1.05; 1.00-1.10), psychiatric disorders (1.38; 1.27-1.50), asthma (1.13; 0.94-1.36), and ALRI (1.14; 1.09-1.20). Associations with long-term exposure to ozone (mean: 80.2 µg/m³) were generally negative but became significantly positive for several endpoints in two-pollutant models. Generally, associations were attenuated but remained significant after indirect adjustment for smoking and BMI.

CONCLUSION

Long-term exposure to PM_2.5, NO₂, and/or BC in Denmark were associated with mortality beyond cardiorespiratory diseases, including diabetes, dementia, psychiatric disorders, asthma, and ALRI.

Long-term nitrogen dioxide exposure and cause-specific mortality in the U.S. Medicare population

BACKGROUND

Since 1971, the annual National Ambient Air Quality Standard (NAAQS) for nitrogen dioxide (NO₂) has remained at 53 ppb, the impact of long-term NO₂ exposure on mortality is poorly understood.

OBJECTIVES

We examined associations between long-term NO₂ exposure (12-month moving average of NO₂) below the annual NAAQS and cause-specific mortality among the older adults in the U.S.

METHODS

Cox proportional-hazard models were used to estimate Hazard Ratio (HR) for cause-specific mortality associated with long-term NO₂ exposures among about 50 million Medicare beneficiaries living within the conterminous U.S. from 2001 to 2008.

RESULTS

A 10 ppb increase in NO₂ was associated with increased mortality from all-cause (HR: 1.06; 95% CI: 1.05-1.06), cardiovascular (HR: 1.10; 95% CI: 1.10-1.11), respiratory disease (HR: 1.09; 95% CI: 1.08-1.11), and cancer (HR: 1.01; 95% CI: 1.00-1.02) adjusting for age, sex, race, ZIP code as strata ZIP code- and state-level socio-economic status (SES) as covariates, and PM_2.5 exposure using a 2-stage approach. NO₂ was also associated with elevated mortality from ischemic heart disease, cerebrovascular disease, congestive heart failure, chronic obstructive pulmonary disease, pneumonia, and lung cancer. We found no evidence of a threshold, with positive and significant HRs across the range of NO₂ exposures for all causes of death examined. Exposure-response curves were linear for all-cause, supra-linear for cardiovascular-, and sub-linear for respiratory-related mortality. HRs were highest consistently among Black beneficiaries.

CONCLUSIONS

Long-term NO₂ exposure is associated with elevated risks of death by multiple causes, without evidence of a threshold response. Our findings raise concerns about the sufficiency of the annual NAAQS for NO₂.

Effect modification by sex for associations of fine particulate matter (PM2.5) with cardiovascular mortality, hospitalization, and emergency room visits: systematic review and meta-analysis

Particulate matter with aerodynamic diameter no larger than 2.5 μm (PM2.5) has been linked to cardiovascular diseases (CVDs) but evidence for vulnerability by sex remains unclear. We performed systematic review and meta-analysis to synthesize the state of scientific evidence on whether cardiovascular risks from PM2.5 differ for men compared to women. The databases Pubmed, Scopus, Embase, and GreenFILE were searched for studies published Jan. 1995 to Feb. 2020. Observational studies conducting subgroup analysis by sex for impacts of short-term or long-term exposure to PM2.5 on target CVDs were included. Data were independently extracted in duplicate and pooled with random-effects meta-regression. Risk ratios (RRs) for long-term exposure and percent changes in outcomes for short-term exposure were calculated per 10 μg/m3 PM2.5 increase. Quality of evidence of risk differences by sex was rated following Grading of Recommendations Assessment, Development and Evaluation (GRADE). A total of 12,502 articles were screened, with 61 meeting inclusion criteria. An additional 32 studies were added from citation chaining. RRs of all CVD mortality for long-term PM2.5 for men and women were the same (1.14; 95% CI: 1.09, 1.22) indicating no statistically different risks. Men and women did not have statistically different risks of daily CVD mortality, hospitalizations from all CVD, ischemic heart disease, cardiac arrest, acute myocardial infarction, and heart failure from short-term PM2.5 exposure (difference in % change in risk per 10 μg/m3 PM2.5: 0.04 (95% CI, -0.42 to 0.51); -0.05 (-0.47 to 0.38); 0.17 (-0.90, 1.24); 1.42 (-1.06, 3.97); 1.33 (-0.05, 2.73); and -0.48 (-1.94, 1.01), respectively). Analysis using GRADE found low or very low quality of evidence for sex differences for PM2.5-CVD risks. In conclusion, this meta-analysis and quality of evidence assessment of current observational studies found very limited evidence of the effect modification by sex for effects of PM2.5 on CVD outcomes in adults, which can inform clinical approaches and policies.

Sex Differences in Cardiovascular Risk Associated With Long-Term PM2.5 Exposure: A Systematic Review and Meta-Analysis of Cohort Studies

Background

Established evidence suggests risks of developing cardiovascular disease are different by sex. However, it remains unclear whether associations of PM_2.5 with cardiovascular risk are comparable between women and men. The meta-analysis aimed to examine sex differences in associations of ischemic heart disease (IHD) and stroke with long-term PM_2.5 exposure.

Methods

PubMed, EMBASE and Cochrane Library were searched until May 2, 2021. We included cohort studies reporting sex-specific associations of long-term PM_2.5 exposure (e.g., ≥1 year) with IHD and stroke. The primary analysis was to estimate relative risk (RR) of PM_2.5-outcome in women and men separately, and the additional women-to-men ratio of RR (RRR) was explored to compare sex differences, using random-effect models.

Results

We identified 25 eligible studies with 3.6 million IHD and 1.3 million stroke cases among 63.7 million participants. A higher level of PM_2.5 exposure was significantly associated with increased risk of IHD in both women (RR = 1.21; 95% CI, 1.15–1.27) and men (RR = 1.12; 95% CI, 1.07–1.17). The women-to-men RRR of IHD was 1.05 (95% CI, 1.02–1.08) per 10 μg/m³ increment in PM_2.5 exposure, indicating significant excess risk of IHD in women. The significant risks of stroke associated with PM_2.5 were obtained in both women (RR = 1.11; 95% CI, 1.08–1.13) and men (RR = 1.11; 95% CI, 1.07–1.14), but no significant women-to-men RRR was observed in stroke (RRR = 1.00; 95% CI, 0.96–1.04).

Conclusions

The study identified excess risk of IHD associated with long-term PM_2.5 exposure in women. The findings would not only have repercussions on efforts to precisely evaluate the burden of IHD attributable to PM_2.5, but would also provide novel clues for cardiovascular risk prevention accounting for sex-based differences.

Multi-step short-term [Formula: see text] forecasting for enactment of proactive environmental regulation strategies

Particulate matter is one of the key contributors of air pollution and climate change. Long-term exposure to constituents of air pollutants has exerted serious health implications in both humans and plants leading to a detrimental impact on economy. Among the pollutants contributing to air quality determination, particulate matter has been linked to serious health implications causing pulmonary complications, cardiovascular diseases, growth retardation and ultimately death. In agriculture, crop yield is also negatively impacted by the deposition of particulate matter on stomata of the plant which is alarming and can cause food security concerns. The deleterious impact of air pollutants on human health, agricultural and economic well-being highlights the importance of quantifying and forecasting particulate matter. Several deterministic and deep learning models have been employed in the recent years to forecast the concentration of particulate matter. Among them, deep learning models have shown promising results when it comes to modeling time series data and forecasting it. We have explored recurrent neural networks with LSTM model which shows potential to predict the particulate matter ([Formula: see text]) based on multi-step multi-variate data of two of the most polluted regions of South Asia, Beijing, China and Punjab, Pakistan effectively. The LSTM model is tuned using Bayesian optimization technique to employ the appropriate hyper-parameters and weight initialization strategies based on the dataset. The model was able to predict [Formula: see text] for the next hour with root-mean-square error (RMSE) of 0.1913 (91.5% accuracy) and this error gradually increases with the number of time steps with next 24 hours steps prediction having RMSE of 0.7290. While in case of Punjab dataset with data recorded once a day, the RMSE for the next day forecast is 0.2192. These multi-step short-term forecasts would play a pivotal role in establishing an early warning system based on the air quality index (AQI) calculated and enable the government in enacting policies to contain it.

Outdoor ambient air pollution and breast cancer survival among California participants of the Multiethnic Cohort Study

BACKGROUND

Within the Multiethnic Cohort (MEC), we examined the association between air pollution and mortality among African American, European American, Japanese American, and Latina American women diagnosed with breast cancer.

METHODS

We used a land use regression (LUR) model and kriging interpolation to estimate nitrogen oxides (NOx , NO2) and particulate matter (PM2.5, PM10) exposures for 3,089 breast cancer cases in the MEC, who were diagnosed from 1993 through 2013 and resided largely in Los Angeles County, California. Cox proportional hazards models were used to examine the association of time-varying air pollutants with all-cause, breast cancer, cardiovascular disease (CVD), and non-breast cancer/non-CVD mortality, accounting for key covariates.

RESULTS

We identified 1,125 deaths from all causes (474 breast cancer, 272 CVD, 379 non-breast cancer/non-CVD deaths) among the 3,089 breast cancer cases with 8.1 years of average follow-up. LUR and kriged NOX (per 50 ppb) and NO2 (per 20 ppb), PM2.5 (per 10 µg/m3), and PM10 (per 10 µg/m3) were positively associated with risks of all-cause (Hazard Ratio (HR) range = 1.13-1.25), breast cancer (HR range = 1.19-1.45), and CVD mortality (HR range = 1.37-1.60). Associations were statistically significant for LUR NOX and CVD mortality (HR = 1.60; 95% CI: 1.08-2.37) and kriged NO2 and breast cancer mortality (HR = 1.45; 95% CI 1.02-2.07). Gaseous and PM pollutants were positively associated with breast cancer mortality across racial/ethnic group.

CONCLUSION

In this study, air pollutants have a harmful impact on breast cancer survival. Additional studies should evaluate potential confounding by socioeconomic factors. These data support maintaining clean air laws to improve survival for women with breast cancer.

The impact of Long-Term PM2.5 constituents and their sources on specific causes of death in a US Medicare cohort

BACKGROUND

Our understanding of the impact of long-term exposures to PM_2.5 constituents and sources on mortality is limited.

OBJECTIVES

To examine associations between long-term exposures to PM_2.5 constituents and sources and cause-specific mortality in US older adults.

METHODS

We obtained demographic and mortality data for 15.4 million Medicare beneficiaries living within the conterminous United States (US) between 2000 and 2008. We assessed PM_2.5 constituents exposures for each beneficiary and used factor analysis and residual-based methods to characterize PM_2.5 sources and mixtures, respectively. In age-, sex-, race- and site- stratified Cox proportional hazard models adjusted for neighborhood socio-economic status (SES), we assessed associations of individual PM_2.5 constituents, sources, and mixtures and cause-specific mortality and examined modification of these associations by participant demographics and location of residence. We assessed the robustness of our findings to additional adjustment for behavioral risk factors and to alternate exposure definitions and exposure windows.

RESULTS

Hazard ratios (HR) were highest for all causes of death, except COPD, for PM_2.5 constituents and the coal combustion-related PM_2.5 components, with no evidence of confounding by behavioral covariates. We further found Pb and metal-related PM_2.5 components to be significantly associated with increased HR of all causes of death, except COPD and lung cancer mortality, and nitrate (NO₃^-) and silicon (Si) and associated source-related PM_2.5 components (traffic and soil, respectively) to be significantly associated with increased all-cause, CVD, respiratory and all cancer-related mortality HR. Associations for other examined constituents and mortality were inconsistent or largely null. Our analyses of mixtures were generally consistent with these findings. Mortality HRs were greatest for minority, especially Black, low-income urban, younger, and male beneficiaries.

DISCUSSION

PM_2.5 components related to coal combustion, traffic, and to a lesser extent, soil were strongly associated with mortality from CVD, respiratory disease, and cancer.

Personal Exposure to Fine Particles (PM2.5) in Northwest Africa: Case of the Urban City of Bamako in Mali

Personal exposure to particulate matter (PM) from anthropogenic activities is a major concern in African countries, including Mali. However, knowledge of particulates is scant. This study was undertaken to characterize personal exposure to PM_2.5 microns or less in diameter (PM_2.5) in the city of Bamako in Mali. The exposure to PM_2.5, through daily activities was observed from September 2020 to February 2021. Participants wore palm-sized optical PM_2.5 sensors on their chest during their daily activities. The exposure levels in four different groups of residents were investigated in relation to their daily activities. The variation in PM_2.5 concentration was measured during different activities in different microenvironments, and the main sources of exposure were identified. The highest average 10 min concentrations were observed at home and in bedrooms, while the participants were using specific products typically used in Africa, Asia, and South America that included insecticides (IST; 999 µg/m³) and incense (ICS; 145 µg/m³), followed by traffic (216 µg/m³) and cooking (150 µg/m³). The lowest average 10 min concentrations were also observed in the same microenvironment lacking IST or ICS (≤14 µg/m³). With no use of specific products, office workers and students were the least exposed, and drivers and cooks were the most exposed. The concentrations are up to 7.5 and 3 times higher than the World Health Organization's yearly and daily recommended exposure levels, respectively, indicating the need to promptly elaborate and apply effective mitigation strategies to improve air quality and protect public health. This study highlights the importance of indoor air pollution sources related to culture and confirms previous studies on urban outdoor air pollution sources, especially in developing countries. The findings could be applied to cities other than Bamako, as similar practices and lifestyles are common in different cultures.

Ambient air pollution associated with lower academic achievement among US children: A nationwide panel study of school districts

Supplemental Digital Content is available in the text.

Background:

Ambient air pollution is an important environmental exposure and has been linked with impaired cognitive function. Few studies have investigated its impact on children’s academic performance on a nationwide level. We hypothesize that higher ambient air pollution concentrations will be associated with lower average academic test scores.

Methods:

We investigated three prevalent ambient air pollutants: PM_2.5, NO₂ and ozone, and their associations with the average academic test scores, at the Geographic School District (GSD) level, of the third to eighth grade students in the United States from 2010 to 2016. We applied multivariate linear regression and controlled for urbanicity, socioeconomic status, student racial/ethnic compositions, and individual intercepts for each district-grade level and each year.

Results:

We found that an interquartile range increase in PM_2.5 concentrations was associated with a 0.007 (95% confidence interval: 0.005, 0.009) SD lower average math test scores, and a 0.004 (95% confidence interval: 0.002, 0.005) SD lower average English language/arts test scores. Similar associations were observed for NO₂ and ozone on math, and for NO₂ on English language/arts. The magnitudes of these associations are equivalent to the effects of short-term reductions of thousands of dollars in district median household income. The reductions in test scores were larger for GSDs with higher socioeconomic status, though most associations remained negative at all socioeconomic levels.

Conclusions:

Our results show that ambient air pollution within a GSD is associated with lower academic performance among children. Further improving air quality may benefit children’s overall academic achievement and socioeconomic attainment across the lifespan.

The cardiovascular effects of air pollution: Prevention and reversal by pharmacological agents

Air pollution is associated with staggering levels of cardiovascular morbidity and mortality. Airborne particulate matter (PM), in particular, has been associated with a wide range of detrimental cardiovascular effects, including impaired vascular function, raised blood pressure, alterations in cardiac rhythm, blood clotting disorders, coronary artery disease, and stroke. Considerable headway has been made in elucidating the biological processes underlying these associations, revealing a labyrinth of multiple interacting mechanistic pathways. Several studies have used pharmacological agents to prevent or reverse the cardiovascular effects of PM; an approach that not only has the advantages of elucidating mechanisms, but also potentially revealing therapeutic agents that could benefit individuals that are especially susceptible to the effects of air pollution. This review gathers investigations with pharmacological agents, offering insight into the biology of how PM, and other air pollutants, may cause cardiovascular morbidity.

MicroRNA-760 resists ambient PM2.5-induced apoptosis in human bronchial epithelial cells through elevating heme-oxygenase 1 expression

PM_2.5 (particles matter smaller aerodynamic diameter of 2.5 μm) exposure, a major environmental risk factor for the global burden of diseases, is associated with high risks of respiratory diseases. Heme-oxygenase 1 (HMOX1) is one of the major molecular antioxidant defenses to mediate cytoprotective effects against diverse stressors, including PM_2.5-induced toxicity; however, the regulatory mechanism of HMOX1 expression still needs to be elucidated. In this study, using PM_2.5 as a typical stressor, we explored whether microRNAs (miRNAs) might modulate HMOX1 expression in lung cells. Systematic bioinformatics analysis showed that seven miRNAs have the potentials to target HMOX1 gene. Among these, hsa-miR-760 was identified as the most responsive miRNA to PM_2.5 exposure. More importantly, we revealed a "non-conventional" miRNA function in hsa-miR-760 upregulating HMOX1 expression, by targeting the coding region and interacting with YBX1 protein. In addition, we observed that exogenous hsa-miR-760 effectively elevated HMOX1 expression, reduced the reactive oxygen agents (ROS) levels, and rescued the lung cells from PM_2.5-induced apoptosis. Our results revealed that hsa-miR-760 might play an important role in protecting lung cells against PM_2.5-induced toxicity, by elevating HMOX1 expression, and offered new clues to elucidate the diverse functions of miRNAs.

Association between air pollution in Lima and the high incidence of COVID-19: findings from a post hoc analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) originated in the People's Republic of China in December 2019. Thereafter, a global logarithmic expansion of cases occurred. Some countries have a higher rate of infections despite the early implementation of quarantine. Air pollution might be related to high susceptibility to the virus and associated case fatality rates (deaths/cases*100). Lima, Peru, has the second highest incidence of COVID-19 in Latin America and also has one the highest levels of air pollution in the region.

METHODS

This study investigated the association of levels of PM2.5 exposure in previous years (2010-2016) in 24 districts of Lima with cases, deaths and case fatality rates for COVID-19. Multiple linear regression was used to evaluate this association controlled by age, sex, population density and number of food markets per district. The study period was from March 6 to June 12, 2020.

RESULTS

There were 128,700 cases in Lima and 2382 deaths due to COVID-19. The case fatality rate was 1.93%. Previous exposure to PM2.5 (2010-2016) was associated with the number of COVID-19- cases (β = 0.07; 95% CI: 0.034-0.107) and deaths (β = 0.0014; 95% CI: 0.0006-0.0.0023) but not with the case fatality rate.

CONCLUSIONS

After adjusting for age, sex and number of food markets, the higher rates of COVID-19 in Metropolitan Lima are attributable to the increased PM2.5 exposure in the previous years, among other reasons. Reduction in air pollution from a long-term perspective and social distancing are needed to prevent the spread of virus outbreaks.

All-Cause Mortality Risk and Attributable Deaths Associated with Long-Term Exposure to Ambient PM2.5 in Chinese Adults

Several recent studies in China have associated raised mortality risks with chronic exposure to ambient PM_2.5. However, cohort evidence covering general populations and more homogeneous regions is extensively scarce. We conceived a nationwide perspective cohort study from 2010 through 2018, by enrolling 30 946 adult men and women aged 16-110 years from 25 provincial regions in mainland China. Cox proportional hazards models with time-varying exposures were adopted to quantify longitudinal association of PM_2.5 exposure with all-cause mortality. A total of 1762 death events occurred during a median follow-up of 8.1 years. Participants were exposed to a broad range of annual mean PM_2.5 concentrations (2.4-112 μg/m³), with an average estimate of 47.5 μg/m³. A 10-μg/m³ increase in annual average of PM_2.5 exposure was associated with an hazard ratio of 1.055 (95% confidence interval: 1.022-1.088, p < 0.001) for all-cause mortality. We estimated totally 2.68 million deaths attributable to ambient PM_2.5 in 2015, yielding a remarkable reduction of 36.7 thousand compared to the estimate in 2010 (2.72 million deaths). This study added nationally representative evidence regarding concentration-response function for long-term PM_2.5-mortality association in Chinese adults, which may significantly contribute to national and global assessments of PM_2.5-attributable death burden.

Concentration-response relationships between hourly particulate matter and ischemic events: A case-crossover analysis of effect modification by season and air-mass origin

Most studies linking cardiovascular disease with particulate matter (PM) exposures have focused on total mass concentrations, regardless of their origin. However, the origin of an air mass is inherently linked to particle composition and possible toxicity. We examine how the concentration-response relation between hourly PM exposure and ischemic events is modified by air-mass origin and season. Using telemedicine data, we conducted a case-crossover study of 1855 confirmed ischemic cardiac events in Israel (2005-2013). Based on measurements at three fixed-sites in Tel Aviv and Haifa, ambient PM with diameter < 2.5 μm (PM_2.5) and 2.5-10 μm (PM_10-2.5) concentrations during the hours before event onset were compared with matched control periods using conditional logistic regression that allowed for non-linearity. We also examined effect modification of these associations based on the geographical origin of each air mass by season. Independent of the geographical origin of the air mass, we observed concentration-response curves that were supralinear. For example, the overall odds ratios (ORs) of ischemic events for an increase of 10-μg/m³ in the 2-h average of PM_10-2.5 were 1.08 (95% confidence interval (CI): 1.03-1.14) and 1.00 (0.99-1.01) at the median (17.8 μg/m³) and 95th percentile (82.3 μg/m³) values, respectively. Associations were strongest at low levels of PM_10-2.5 when air comes from central Europe in the summer (OR: 1.27; 95% CI: 1.06, 1.52). Our study demonstrates that hourly associations between PM_2.5 and PM_10-2.5 and ischemic cardiac events are supralinear during diverse pollution conditions in a single population that experiences a wide range of exposure levels.

"Association between air pollution in Lima and the high incidence of COVID-19: findings from a post hoc analysis."

Background Corona virus disease (COVID-19) originated in China in December 2019. Thereafter, a global logarithmic expansion of the cases has occurred. Some countries have a higher rate of infections despite of early implementation of quarantine. Air pollution could be related to the high susceptibility to SARS-CoV-2 and the associated case-fatality rates (deaths/cases*100). Lima, Peru has the second highest incidence of COVID-19 in Latin America, and it is also one of the cities with highest levels of air pollution in the Region. Methods This study investigated the association of the levels of PM _2.5 exposure in the previous years (2010-2016) in 24 districts of Lima with the positive-cases, deaths and case-fatality rates of COVID-19. Multiple Linear regression was used to evaluate this association controlled by age, sex, population density and number of food markets per district. The study period was from March 6 to June 12, 2020. Results There were in Lima 128,700 SARS-CoV-2 positive cases, and 2,382 deaths due to COVID-19. The case-fatality rate was 1.93%. Previous exposure to PM _2.5 (years 2010-2016) was associated with number of Covid-19 positive-cases ( β  = 0.07; 95% CI: 0.034-0.107) and deaths ( β  = 0.0014; 95% CI: 0.0006-0.0.0023), but not with case-fatality rate. Conclusions the higher rates of COVID-19 in Metropolitan Lima is attributable, among others, to the increased PM _2.5 exposure in the previous years after adjusting for age, sex and number of food markets. Reduction of air pollution since a long-term perspective, and social distancing are needed to prevent spreads of virus outbreak.

Air Quality Enhancement Districts: democratizing data to improve respiratory health

The U.S. Centers for Disease Control and Prevention has recently acknowledged that the principal mode for SARS-CoV-2 (the virus that causes COVID-19) to spread is through airborne particles. Reducing levels of particulate matter, a form of air pollutant, may decrease the spread of the virus and save lives. In this article, we propose establishing local Air Quality Enhancement Districts using low-cost air quality sensors. Air quality sensors provide more detailed data on particulate matter concentrations than what is currently provided by the U.S. Environmental Protection Agency, which will allow communities and individuals to make better informed decisions about activities during poor air quality days. The core principles behind local Air Quality Enhancement Districts is to (1) provide citizens with more localized data on air quality, (2) raise awareness on localized pollution and health impacts related to COVID-19, and (3) empower citizens and local governments to take quick actions to reduce exposure and respiratory distress during times of poor air quality.