Ambient Air Pollution and Out-of-Hospital Cardiac Arrest in Beijing, China

Short-Term Ambient Air Pollution Exposure and Risk of Out-of-Hospital Cardiac Arrest in Sweden: A Nationwide Case-Crossover Study

Background Air pollution is one of the main risk factors for cardiovascular disease globally, but its association with out-of-hospital cardiac arrest at low air pollution levels is unclear. This nationwide study in Sweden aims to investigate if air pollution is associated with a higher risk of out-of-hospital cardiac arrest in an area with relatively low air pollution levels. Methods and Results This study was a nationwide time-stratified case-crossover study investigating the association between short-term air pollution exposures and out-of-hospital cardiac arrest using data from the SRCR (Swedish Registry for Cardiopulmonary Resuscitation) between 2009 and 2019. Daily air pollution levels were estimated in 1×1-km grids for all of Sweden using a satellite-based machine learning model. The association between daily air pollutant levels and out-of-hospital cardiac arrest was quantified using conditional logistic regression adjusted for daily air temperature. Particulate matter <2.5 μm exposure was associated with a higher risk of out-of-hospital cardiac arrest among a total of 29 604 cases. In a multipollutant model, the association was most pronounced for intermediate daily lags, with an increased relative risk of 6.2% (95% CI, 1.0-11.8) per 10 μg/m3 increase of particulate matter <2.5 μm 4 days before the event. A similar pattern of association was observed for particulate matter <10 μm. No clear association was observed for O3 and NO2. Conclusions Short-term exposure to air pollution was associated with higher risk of out-of-hospital cardiac arrest. The findings add to the evidence of an adverse effect of particulate matter on out-of-hospital cardiac arrest, even at very low levels below current regulatory standards.

Fine and coarse particulate air pollution and out-of-hospital cardiac arrest onset: a nationwide case-crossover study in China

Out-of-hospital cardiac arrest (OHCA) is a global public health concern. Nationwide studies on the effects of short-term exposure to particulate matter (PM) on OHCA risk are rare in regions with high PM levels, and evidence for coarse PM (PM_2.5-10) is limited and inconsistent. To evaluate the associations between fine PM (PM_2.5) and PM_2.5-10 and OHCA onset, a time-stratified case-crossover study was conducted on 77,261 patients with cardiac OHCA in 26 cities across China in 2020. Daily PM_2.5 and PM_2.5-10 concentrations were assessed with high-resolution and full-coverage PM estimations. Conditional logistic regression models were applied in analyses. Each interquartile range of PM increase in 3-day moving average was associated with an increased risk of cardiac OHCA onset of 2.37% (95% CI, 1.20-3.56%) for PM_2.5 and 2.12% (95% CI, 0.70-3.56%) for PM_2.5-10. Stratified analyses showed higher susceptibility in patients over 75 years for PM_2.5 exposure and with diabetes for PM_2.5-10. This first nationwide study in region with high PM levels and great PM variability found not only PM_2.5 but also PM_2.5-10 were associated with a higher risk of OHCA onset, which could add powerful epidemiological evidence to this field and provide new evidence for the formulation of air quality guidelines.

Ambient air pollution and emergency department visits and hospitalisation for cardiac arrest: a population-based case-crossover study in Reykjavik, Iceland

OBJECTIVES

To assess the association between traffic-related ambient air pollution and emergency hospital visits for cardiac arrest.

DESIGN

Case-crossover design was used with a lag time to 4 days.

SETTING

The Reykjavik capital area and the study population was the inhabitants 18 years and older identified by encrypted personal identification numbers and zip codes.

PARTICIPANTS AND EXPOSURE

Cases were those with emergency visits to Landspitali University Hospital during the period 2006-2017 and who were given the primary discharge diagnosis of cardiac arrest according to the International Classification of Diseases 10th edition (ICD-10) code I46. The pollutants were nitrogen dioxide (NO₂), particulate matter with aerodynamic diameter less than 10 µm (PM₁₀), particulate matter with aerodynamic diameter less than 2.5 µm (PM_2.5) and sulfur dioxide (SO₂) with adjustment for hydrogen sulfide (H₂S), temperature and relative humidity.

MAIN OUTCOME MEASURE

OR and 95% CIs per 10 µg/m³ increase in concentration of pollutants.

RESULTS

The 24-hour mean NO₂ was 20.7 µg/m³, mean PM₁₀ was 20.5 µg/m³, mean PM_2.5 was 12.5 µg/m³ and mean SO₂ was 2.5 µg/m³. PM₁₀ level was positively associated with the number of emergency hospital visits (n=453) for cardiac arrest. Each 10 µg/m³ increase in PM₁₀ was associated with increased risk of cardiac arrest (ICD-10: I46), OR 1.096 (95% CI 1.033 to 1.162) on lag 2, OR 1.118 (95% CI 1.031 to 1.212) on lag 0-2, OR 1.150 (95% CI 1.050 to 1.261) on lag 0-3 and OR 1.168 (95% CI 1.054 to 1.295) on lag 0-4. Significant associations were shown between exposure to PM₁₀ on lag 2 and lag 0-2 and increased risk of cardiac arrest in the age, gender and season strata.

CONCLUSIONS

A new endpoint was used for the first time in this study: cardiac arrest (ICD-10 code: I46) according to hospital discharge registry. Short-term increase in PM₁₀ concentrations was associated with cardiac arrest. Future ecological studies of this type and their related discussions should perhaps concentrate more on precisely defined endpoints.

Short-Term Exposure to Sulfur Dioxide and Nitrogen Monoxide and Risk of Out-of-Hospital Cardiac Arrest

BACKGROUND & AIMS

Over the past decades, particulate matter (PM), especially fine PM <2.5 μm in aerodynamic diameter (PM_2.5) has been a major research focus. However, the air pollutant is a mixture of gases or vapour-phase compounds, such as carbon monoxide (C), nitrogen oxides (NO_x), photochemical oxidants (Ox), and sulfur dioxide (SO₂). Little is known about their cardiovascular effect, individually or in combination with PM. Thus, we aimed to determine the associations between the incidence of acute cardiac events and both gaseous and PM using a case-crossover design.

METHODS

Cardiovascular cases were identified through the Gunma Prefectural Ambulance Activity Database in Japan in 2015 (1,512 out-of-hospital cardiac arrest [OHCA] and 1,002 heart failures from 53,006 ambulance cases). Air quality data from the nearest station was for day of the arrest (lag0) and 1-2 days before the arrest (lag1, lag2) and the moving average across days 0-1 (lag0-1). Conditional logistic regression was used for unadjusted and adjusted analysis for temperature and humidity.

RESULTS

Independent associations of OHCA were daily concentrations of SO₂ at lag1 (OR 1.173, 95%CI 1.004, 1.370; p=0.044) and lag0-1 (OR 1.203, 95%CI 1.015, 1.425; p=0.033); and daily NO concentrations at lag2 (OR 1.039, 95%CI 1.007, 1.072; p=0.016). The incidence of heart failure was significantly associated with daily concentrations of O_x on the day of the event in univariable model but not after adjustment for temperature and humidity. No associations were found for other pollutants.

CONCLUSIONS

Short-term exposure to SO₂ and NO are associated with an increased risk of OHCA.

Impact of Air Pollution and COVID-19 Infection on Periprocedural Death in Patients with Acute Coronary Syndrome

Air pollution and COVID-19 infection affect the pathogenesis of cardiovascular disease. The impact of these factors on the course of ACS treatment is not well defined. The purpose of this study was to evaluate the effects of air pollution, COVID-19 infection, and selected clinical factors on the occurrence of perioperative death in patients with acute coronary syndrome (ACS) by developing a neural network model. This retrospective study included 53,076 patients with ACS from the ORPKI registry (National Registry of Invasive Cardiology Procedures) including 2395 COVID-19 (+) patients and 34,547 COVID-19 (-) patients. The neural network model developed included 57 variables, had high performance in predicting perioperative patient death, and had an error risk of 0.03%. Based on the analysis of the effect of permutation on the variable, the variables with the greatest impact on the prediction of perioperative death were identified to be vascular access, critical stenosis of the left main coronary artery (LMCA) or left anterior descending coronary artery (LAD). Air pollutants and COVID-19 had weaker effects on end-point prediction. The neural network model developed has high performance in predicting the occurrence of perioperative death. Although COVID-19 and air pollutants affect the prediction of perioperative death, the key predictors remain vascular access and critical LMCA or LAD stenosis.

Kidney damage induced by repeated fine particulate matter exposure: Effects of different components

BACKGROUND

Exposure to fine particulate matter with an aerodynamic diameter of ≤2.5 μm (PM_2.5) is associated with adverse health effects. This study aimed to evaluate the toxic effects of the constituents of PM_2.5 on mouse kidneys.

METHODS

We collected PM_2.5 near an industrial complex located in southern Kaohsiung, Taiwan, that was divided into water extract and insoluble particles. Male C57BL/6 mice were divided into five groups: control, low- and high-dose insoluble particle exposure, and low- and high-dose water extract exposure. Biochemical analysis, Western blot analysis, histological examination, and immunohistochemistry were performed to evaluate the impact of PM_2.5 constituents on mice kidneys.

RESULTS

PM_2.5 was collected from January 1, 2021, to February 8, 2021, from an industrial complex in Kaohsiung, Taiwan. Metallic element analysis showed that Pb, Ni, V, and Ti were non-essential metals with enrichment factors >10. Polycyclic aromatic hydrocarbon and nitrate polycyclic aromatic hydrocarbon analyses revealed that the toxic equivalents are, in the order, benzo(a)pyrene (BaP), indeno(1,2,3-cd) pyrene (IP), dibenzo(a,h)anthracene (DBA), and benzo(b)fluoranthene (BbF), which are potential carcinogens. Both water extract and insoluble particle exposure induced inflammatory cytokine upregulation, inflammatory cell infiltration, antioxidant activity downregulation, and elevation of kidney injury molecule 1 (KIM-1) level in mouse kidneys. A dose-dependent effect of PM_2.5 water extract and insoluble particle exposure on angiotensin converter enzyme 2 downregulation in mouse kidneys was observed.

CONCLUSION

We found that water-soluble extract and insoluble particles of PM_2.5 could induce oxidative stress and inflammatory reactions, influence the regulation of renin-angiotensin system (RAS), and lead to kidney injury marker level elevation in mouse kidneys. The lowest-observed-adverse-effect level for renal toxicity in mice was 40 μg water-soluble extract/insoluble particle inhalation per week, which was approximately equal to the ambient PM_2.5 concentration of 44 μg/m³ for mice.

Synergistic or Antagonistic Health Effects of Long- and Short-Term Exposure to Ambient NO2 and PM2.5: A Review

Studies on adverse health effects associated with air pollution mostly focus on individual pollutants. However, the air is a complex medium, and thus epidemiological studies face many challenges and limitations in the multipollutant approach. NO₂ and PM_2.5 have been selected as both originating from combustion processes and are considered to be the main pollutants associated with traffic; moreover, both elicit oxidative stress responses. An answer to the question of whether synergistic or antagonistic health effects of combined pollutants are demonstrated by pollutants monitored in ambient air is not explicit. Among the analyzed studies, only a few revealed statistical significance. Exposure to a single pollutant (PM_2.5 or NO₂) was mostly associated with a small increase in non-accidental mortality (HR:1.01-1.03). PM_2.5 increase of <10 µg/m³ adjusted for NO₂ as well as NO₂ adjusted for PM_2.5 resulted in a slightly lower health risk than a single pollutant. In the case of cardiovascular heart disease, mortality evoked by exposure to PM_2.5 or NO₂ adjusted for NO₂ and PM_2.5, respectively, revealed an antagonistic effect on health risk compared to the single pollutant. Both short- and long-term exposure to PM_2.5 or NO₂ adjusted for NO₂ and PM_2.5, respectively, revealed a synergistic effect appearing as higher mortality from respiratory diseases.

Ambient Air Pollution and Risk for Stroke Hospitalization: Impact on Susceptible Groups

Stroke is a leading cause of death, and air pollution is associated with stroke hospitalization. However, the susceptibility factors are unclear. Retrospective studies from 2014 to 2018 in Kaohsiung, Taiwan, were analyzed. Adult patients (>17 years) admitted to a medical center with stroke diagnosis were enrolled and patient characteristics and comorbidities were recorded. Air pollutant measurements, including those of particulate matter (PM) with aerodynamic diameters < 10 μm (PM10) and < 2.5 μm (PM2.5), nitrogen dioxide (NO2), and ozone (O3), were collected from air quality monitoring stations. During the study period, interquartile range (IQR) increments in PM2.5 on lag3 and lag4 were 12.3% (95% CI, 1.1−24.7%) and 11.5% (95% CI, 0.3−23.9%) concerning the risk of stroke hospitalization, respectively. Subgroup analysis revealed that the risk of stroke hospitalization after exposure to PM2.5 was greater for those with advanced age (≥80 years, interaction p = 0.045) and hypertension (interaction p = 0.034), after adjusting for temperature and humidity. A dose-dependent effect of PM2.5 on stroke hospitalization was evident. This is one of few studies focusing on the health effects of PM2.5 for patients with risk factors of stroke. We found that patients with risk factors, such as advanced age and hypertension, are more susceptible to PM2.5 impacts on stroke hospitalization.

PM2.5 Synergizes With Pseudomonas aeruginosa to Suppress Alveolar Macrophage Function in Mice Through the mTOR Pathway

High concentrations of PM2.5 in enclosed broiler houses cause respiratory disorders in humans and animals. Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen that can induce severe respiratory disease in animals under stress or with abnormal immune functions. Alveolar macrophages are lung-resident immune cells that play important roles in lung host defence and immune balance. In this study, the mechanism by which PM2.5 synergizes with P. aeruginosa to damage alveolar macrophage function and induce inflammation was investigated. The results will provide a theoretical basis for improving the poultry breeding environment and preventing the recurrence of infection with P. aeruginosa. Alveolar macrophages were stimulated by PM2.5 collected in an enclosed broiler house and P. aeruginosa. Phagocytosis was determined by the neutral red test. The apoptosis rate and cytoskeleton changes were observed by flow cytometry assays and laser scanning confocal microscopy. Protein levels related to autophagy and the mTOR pathway were detected by Western blotting. The results indicated that PM2.5 in combination with P. aeruginosa could decrease phagocytosis, inhibit autophagy, increase apoptosis, and destroy the cytoskeleton in alveolar macrophages. In addition, alveolar macrophages had significantly increased expression of mTOR pathway-related proteins in response to the synergistic stimulation of PM2.5 and P. aeruginosa. The above results confirmed that PM2.5 in poultry houses synergized with P. aeruginosa to impede alveolar macrophage function and caused more severe respiratory system injuries through a process closely related to the activation of the mTOR signalling pathway.

Overall and gender-specific associations between marital status and out-of-hospital coronary death during acute coronary events: a cross-sectional study based on data linkage in Beijing, China

OBJECTIVES

To assess overall and gender-specific associations between marital status and out-of-hospital coronary death (OHCD) compared with patients surviving to hospital admission.

DESIGN

A cross-sectional study based on linkage of administrative health databases.

SETTING

Beijing, China.

PARTICIPANTS

From 2007 to 2019, 378 883 patients with acute coronary event were identified in the Beijing Monitoring System for Cardiovascular Diseases, a validated city-wide registration system based on individual linkage of vital registration and hospital discharge data.

OUTCOME MEASURES

OHCD was defined as coronary death occurring before admission. Multilevel modified Poisson regression models were used to calculate the prevalence ratios (PR) and 95% CIs.

RESULTS

Among 378 883 acute coronary events, OHCD accounted for 33.8%, with a higher proportion in women compared with men (41.5% vs 28.7%, p<0.001). Not being married was associated with a higher proportion of OHCD in both genders, with a stronger association in women (PR 2.18, 95% CI 2.10 to 2.26) than in men (PR 1.97, 95% CI 1.91 to 2.02; p for interaction <0.001). The associations of OHCD with never being married (PR 1.98, 95% CI 1.88 to 2.08) and being divorced (PR 2.54, 95% CI 2.42 to 2.67) were stronger in men than in women (never married: PR 0.98, 95% CI 0.82 to 1.16; divorced: PR 1.47, 95% CI 1.34 to 1.61) (p for interaction <0.001 for both). Being widowed was associated with a higher proportion of OHCD in both genders, with a stronger association in women (PR 2.26, 95% CI 2.17 to 2.35) compared with men (PR 1.89, 95% CI 1.84 to 1.95) (p for interaction <0.001).

CONCLUSIONS

Not being married was independently associated with a higher proportion of OHCD and the associations differed by gender. Our study may aid the development of gender-specific public health interventions in high-risk populations characterised by marital status to reduce OHCD burden.

Selecting Data Analytic and Modeling Methods to Support Air Pollution and Environmental Justice Investigations: A Critical Review and Guidance Framework

Given the serious adverse health effects associated with many pollutants, and the inequitable distribution of these effects between socioeconomic groups, air pollution is often a focus of environmental justice (EJ) research. However, EJ analyses that aim to illuminate whether and how air pollution hazards are inequitably distributed may present a unique set of requirements for estimating pollutant concentrations compared to other air quality applications. Here, we perform a scoping review of the range of data analytic and modeling methods applied in past studies of air pollution and environmental injustice and develop a guidance framework for selecting between them given the purpose of analysis, users, and resources available. We include proxy, monitor-based, statistical, and process-based methods. Upon critically synthesizing the literature, we identify four main dimensions to inform method selection: accuracy, interpretability, spatiotemporal features of the method, and usability of the method. We illustrate the guidance framework with case studies from the literature. Future research in this area includes an exploration of increasing data availability, advanced statistical methods, and the importance of science-based policy.

The influence of air pollution by PM2.5, PM10 and associated heavy metals on the parameters of out-of-hospital cardiac arrest

Out-of-hospital cardiac arrest (OHCA), defined as abrupt cessation of mechanical activity of the heart, is one of the most common causes of death in high-income countries. Cardiac arrest is most often a result of severe cardiovascular disease. New evidence shows that air pollutants such as heavy metals and atmospheric particulate matter have an impact on the pathophysiology of many cardiovascular diseases as well on incidences of OHCA. This retrospective analysis includes all OHCA cases that occurred in central Poland covering the area of 11.711 km² with the population density of 108 people per square kilometer. Among 2878 EMS-treated OHCA cases between 2013 and 2016, cardiopulmonary resuscitation (CPR) was attempted in 2076 (72%) patients. Concentrations of air pollutants were compared with temperature, humidity and clinical factors affecting the CPR. The study shows seasonal variation of PM 2.5 (p < 0.001), PM 10 (p < 0.001), As (p < 0.001) and Cd (p < 0.001) over the years. Air pollution has a significant effect on the parameters of pre-hospital evaluation in OHCA patients, especially with respect to the content of PM2.5/PM10 and heavy metals. Nickel exposure affects the incidence of initial shockable rhythm (IRR 0.92; p = 0.01) and effectiveness of CPR (IRR 0.94; p = 0.003). Arsenic has an impact on overall mortality (IRR 1.07; p = 0.01) and death upon the arrival of EMS team (IRR 1.15; p < 0.001). Overall mortality was also related to ambient levels of PM10 (IRR 1.004; p < 0.047).

Repeated exposure to fine particulate matter constituents lead to liver inflammation and proliferative response in mice

BACKGROUND

Fine particulate matter (particulate matter with aerodynamic diameter of ≦2.5 µm, PM2.5) exposure cause adverse health effects, including lung inflammation. Through intra-tracheal instillation of PM2.5 components, the study aimed to evaluate the inflammatory and proliferative effects on mice liver. PM2.5 samples were collected near an industrial complex at southern Taiwan. Mice were exposed to water extracts or insoluble particles by intra-tracheal instillation. Male C57BL/6 mice were divided into five groups: control, low dose insoluble particle exposure (LP), high dose insoluble particle exposure (HP), low dose water extract exposure (LW), and high dose water extract exposure (HW). Biochemical analysis, western blotting, histological examination, and immunohistochemistry were employed to evaluate the results.

RESULT

Enrichment factor (EF) of metallic elements showed that the EFs of trace elements (Ti, V, Ni, Zn, Pb, Cr, and Cu) in PM2.5 were above 10. Hematoxylin and Eosin (H&E) staining of the liver tissue showed inflammatory infiltration in particle exposure group; hepatocyte ballooning degeneration and karyomegaly were seen in the water extract exposure group. Upregulation of inflammatory signaling, p65 and p50, and caspase-3 (an important effector involved in apoptosis) positive hepatocytes was significantly increased in the HP group, followed by an elevation in protein levels of growth arrest and DNA damage-inducible protein 153 (GADD153). Increased protein expression of proliferating cell nuclear antigen (PCNA) was noted in the LW and HW groups. An increase in phosphorylation of regulators of cell proliferation, Akt and extracellular signal-regulated kinase (ERK) 1/2, were detected in the LW and HW groups.

CONCLUSION

The present study shows that the insoluble particle composition of PM2.5 induced inflammatory signaling and cytokines upregulation in the liver, accompanied with inflammatory cell and macrophage infiltration and an abnormal liver function. Exposure of water extract to PM2.5 induced signals of upregulated cellular proliferation, elevated markers of cell proliferation in liver, hepatocyte ballooning degeneration and karyomegaly.

Relationship between different air pollutants and total and cause-specific emergency ambulance dispatches in Shanghai, China

OBJECTIVE

Air pollutants play a crucial role in human health and disease. Emergency ambulance dispatch data have excellent potential for public and environmental health research. This study aimed at investigating the impact of short-term exposure to air pollutants on the emergency ambulance dispatches.

METHODS

We used data on emergency ambulance dispatches in Shanghai Municipality, China, from April 1, 2016 to December 31, 2017. The association of the daily emergency ambulance dispatches with air pollutants including PM_2.5 (particles ≤ 2.5 μm in aerodynamic diameter), PM₁₀, O₃, NO₂ and SO₂ was analyzed with the use of time-series analyses.

RESULTS

A total of 310,825 emergency ambulance dispatches for acute illness occurred in Shanghai during the study period. An increase in PM_2.5 by 10 μg/m³ at lag1 and lag2 was shown to increase the risk of emergency ambulance dispatches (RR for lag1 = 1.05, 95% CI 1.00-1.11, RR for lag2 = 1.07, 95% CI 1.01-1.12). PM₁₀, NO₂, and SO₂ also showed significant associations with emergency ambulance dispatches in single-pollutant models. Cause-specific analyses showed an elevation in PM_2.5 by 10 μg/m³ was associated with an increased risk of emergency ambulance dispatches related to respiratory diseases on the current day (lag0, RR 1.17, 95% CI 1.01-1.33), while the impact on emergency ambulance dispatches related to other diseases presented 1-3 days later. The other pollutants have the similar trend.

CONCLUSIONS

Our findings show a strong relationship between ambient air pollutants and emergency ambulance dispatches. Our study contributes to the growing body of evidence describing the adverse health effects of ambient air pollution and will benefit ambulance services for early warning and effective ambulatory planning.

Travelling to polluted cities: a systematic review on the harm of air pollution on international travellers' health

RATIONALE FOR REVIEW

In 2019, approximately, 1.4 billion people travelled internationally. Many individuals travel to megacities where air pollution concentrations can vary significantly. Short-term exposure to air pollutants can cause morbidity and mortality related to cardiovascular and respiratory disease, with the literature clearly reporting a strong association between short-term exposure to particulate matter ≤2.5 μm and ozone with adverse health outcomes in resident populations. However, limited research has been conducted on the health impacts of short-term exposure to air pollution in individuals who travel internationally. The objective of this systematic review was to review the evidence for the respiratory and cardiovascular health impacts from exposure to air pollution during international travel to polluted cities in adults aged ≥18 years old.

KEY FINDINGS

We searched PubMed, Scopus and EMBASE for studies related to air pollution and the health impacts on international travellers. Of the initially identified 115 articles that fit the search criteria, 6 articles were selected for the final review. All six studies found indications of adverse health impacts of air pollution exposure on international travellers, with most of the changes being reversible upon return to their home country/city. However, none of these studies contained large populations nor investigated vulnerable populations, such as children, elderly or those with pre-existing conditions.

CONCLUSIONS

More research is warranted to clearly understand the impacts of air pollution related changes on travellers' health, especially on vulnerable groups who may be at higher risk of adverse impacts during travel to polluted cities.

Identification of exosome miRNAs in bronchial epithelial cells after PM2.5 chronic exposure

Numerous epidemiological studies have demonstrated that chronic PM2.5 exposure was associated with the lung carcinogenesis without known potential mechanisms. Exosomes-derived non-coding RNAs, including miRNAs, are proposed to play critical role in the occurrence and development of malignant diseases. So identification of exosomes-derived miRNAs could help us to better understand the molecular toxicity of PM2.5-induced lung cancer. Establishment chronic exposure animal and cell model with PM2.5 was conducted as before. HE staining was used for estimating the histological alternations of lungs in vivo. The expressions of EMT markers in vivo and vitro were quantified by Western blot. Then the exosomes in cell culture supernatant were extracted and the involved miRNAs were extracted and sequenced. The different expression level of miRNAs were verified by RT-PCR. Chronic PM2.5 exposure induced bronchial epithelial cell atypical hyperplasia and massive macrophage infiltration. PM2.5 exposure induce EMT event in vivo and vitro indicated as increased expression of Vimentin and decreased expression of E-cadherin. And five passages of PM2.5 stimulation also induced the release of rich and extractable exosomes in the cell culture supernatant in vitro. Through sequencing, there were differentially expressed 36 miRNAs between PM2.5 chronic exposed and control groups with 1.5-fold and greater differences. Among them, there were 30 exosome-miRNAs upregulated and 6 downregulated expression by PM2.5 exposure. The downregulated expression of miR-29b-2-5p, miR-193b-5p and miR-320c and upregulated expression of miR-100-5p, 125b-5p and unconservative_2_45093 in PM2.5 group were identified and reconfirmed by qRT-PCR. Chronic PM2.5 exposure causes bronchial epithelial cells atypical hyperplasia and induces EMT event in vivo, and it also induce the expression differences of miRNAs in exosome in vitro. Meanwhile, the identified differentially expressed exosome-miRNAs may partially associate with tumorigenesis. To sum up, the identified exosome-miRNAs may play role in the development of lung cancer induced by chronic PM2.5 exposure.

Short-Term Effects of Particulate Matter and Its Constituents on Emergency Room Visits for Chronic Obstructive Pulmonary Disease: A Time-Stratified Case-Crossover Study in an Urban Area

Background: PM_2.5 exposure is associated with pulmonary and airway inflammation, and the health impact might vary by PM_2.5 constitutes. This study evaluated the effects of increased short-term exposure to PM_2.5 constituents on chronic obstructive pulmonary disease (COPD)-related emergency department (ED) visits and determined the susceptible groups. Methods: This retrospective observational study performed in a medical center from 2007 to 2010, and enrolled non-trauma patients aged >20 years who visited the emergency department (ED) and were diagnosed as COPD. Concentrations of PM_2.5, PM₁₀, and the four PM_2.5 components, including organic carbon (OC), elemental carbon (EC), nitrate (NO₃⁻), and sulfate (SO₄²⁻), were collected by three PM supersites in Kaohsiung City. We used an alternative design of the Poisson time series regression models called a time-stratified and case-crossover design to analyze the data. Results: Per interquartile range (IQR) increment in PM_2.5 level on lag 2 were associated with increments of 6.6% (95% confidence interval (CI), 0.5–13.0%) in risk of COPD exacerbation. An IQR increase in elemental carbon (EC) was significantly associated with an increment of 3.0% (95% CI, 0.1–5.9%) in risk of COPD exacerbation on lag 0. Meanwhile, an IQR increase in sulfate, nitrate, and OC levels was not significantly associated with COPD. Patients were more sensitive to the harmful effects of EC on COPD during the warm season (interaction p = 0.019). The risk of COPD exacerbation after exposure to PM_2.5 was higher in individuals who are currently smoking, with malignancy, or during cold season, but the differences did not achieve statistical significance. Conclusion: PM_2.5 and EC may play an important role in COPD events in Kaohsiung, Taiwan. Patients were more susceptible to the adverse effects of EC on COPD on warm days.

Short-Term Effects of Air Pollution on Cardiovascular Hospitalizations in the Pisan Longitudinal Study

Air pollution effects on cardiovascular hospitalizations in small urban/suburban areas have been scantly investigated. Such effects were assessed among the participants in the analytical epidemiological survey carried out in Pisa and Cascina, Tuscany, Italy (2009–2011). Cardiovascular hospitalizations from 1585 subjects were followed up (2011–2015). Daily mean pollutant concentrations were estimated through random forests at 1 km (particulate matter: PM₁₀, 2011–2015; PM_2.5, 2013–2015) and 200 m (PM₁₀, PM_2.5, NO₂, O₃, 2013–2015) resolutions. Exposure effects were estimated using the case-crossover design and conditional logistic regression (odds ratio—OR—and 95% confidence interval—CI—for 10 μg/m³ increase; lag 0–6). During the period 2011–2015 (137 hospitalizations), a significant effect at lag 0 was observed for PM₁₀ (OR = 1.137, CI: 1.023–1.264) at 1 km resolution. During the period 2013–2015 (69 hospitalizations), significant effects at lag 0 were observed for PM₁₀ (OR = 1.268, CI: 1.085–1.483) and PM_2.5 (OR = 1.273, CI: 1.053–1.540) at 1 km resolution, as well as for PM₁₀ (OR = 1.365, CI: 1.103–1.690), PM_2.5 (OR = 1.264, CI: 1.006–1.589) and NO₂ (OR = 1.477, CI: 1.058–2.061) at 200 m resolution; significant effects were observed up to lag 2. Larger ORs were observed in males and in subjects reporting pre-existent cardiovascular/respiratory diseases. Combining analytical and routine epidemiological data with high-resolution pollutant estimates provides new insights on acute cardiovascular effects in the general population and in potentially susceptible subgroups living in small urban/suburban areas.

The contribution of PM2.5 to cardiovascular disease in China

China is experiencing rapid urbanization and industrialization with correspondingly high levels of air pollution. Although the harm of PM2.5 has been long reported, it is only quite recently that there is increasing concern in China for its possible adverse health effects on cardiovascular disease. We reviewed the epidemiologic evidence of potential health effects of PM2.5 on cardiovascular disease reported from recent studies in China (2013 onwards). There is clear evidence for the contribution of PM2.5 to cardiovascular outcomes, including mortality, ischemic heart disease, and stroke from studies based in various regions in China. This evidence adds to the global evidence that PM2.5 contributes to adverse cardiovascular health risk and highlights the need for improved air quality in China.

Association between ambient air pollution and out-of-hospital cardiac arrest: are there potentially susceptible groups?

This study aimed to examine the association between air pollution and out-of-hospital cardiac arrest (OHCA), and the effects of underlying diseases. Between January 2015 and December 2016, data on particulate matter (PM)_2.5 and other air pollutants in Kaohsiung City were collected, and an emergency medical service database was used for information on patients who experienced OHCA. Overall, 3566 patients were analyzed and subgroup analyses by sex, age, and preexisting morbidities were performed. Interquartile increments in PM_2.5, PM₁₀, and O₃ levels on lag 1 and NO₂ level on lag 3 were associated with increments of 10.8%, 11.3%, 6.2%, and 1.7% in OHCA incidence, respectively. Subgroup analyses showed that patients with diabetes (1.363; interaction p = 0.009), heart disease (1.612; interaction p = 0.001), and advanced age (≥70 years, 1.297; interaction p = 0.003) were more susceptible to NO₂ on lag 3. Moreover, patients were more susceptible to O₃ during the cold season (1.194; interaction p = 0.001). We found that PM_2.5, PM₁₀, NO₂, and O₃ may play an important role in OHCA events, and the effects vary by underlying condition, age and season.

Relationship between different particle size fractions and all-cause and cause-specific emergency ambulance dispatches

BACKGROUND

Evidence on the relationship between different particle size fractions and emergency ambulance dispatches (EAD) remains limited and sparse.

METHODS

We collected daily data of EAD, ambient air pollution and meteorological data from 2014 to 2018 in Guangzhou, China. We used a generalized additive model with covariate adjustments to estimate the associations between different particle size fractions and EAD related to all-cause, cardiovascular diseases, and respiratory diseases. Several subgroup and sensitivity analyses were also performed.

RESULTS

Significant associations were observed between PM_2.5, PM_2.5-10, PM₁₀ and EADs. A 10 μg/m³ increase of PM_2.5, PM_2.5-10, and PM₁₀ was associated with an increase of 0.98% (95% CI: 0.67, 1.28%), 2.06% (95% CI: 1.44, 2.68%), and 0.75% (95%CI: 0.53, 0.96%) in all-cause EAD, with an increase of 0.69% (95% CI: 0.00, 1.39%), 2.04% (95% CI: 0.64, 3.45%), and 0.60% (95%CI: 0.11,1.10%) in cardiovascular-related EAD, and an increase of 1.14% (95% CI: 0.25, 2.04%), 2.52% (95% CI: 0.72, 4.35%), and 0.89% (95%CI: 0.25,1.52%) in respiratory-related EAD at lag03, respectively. The results were robust in subgroup and sensitivity analyses.

CONCLUSIONS

This study revealed that PM_2.5, PM_2.5-10 and PM₁₀ were significantly related with risks of all-cause and cause-specific EAD. More evidence of high quality may be needed to further support our results in this ecological study.

Short-term exposure to ambient fine particulate matter and out-of-hospital cardiac arrest: a nationwide case-crossover study in Japan

BACKGROUND

PM_2·5 is an important but modifiable environmental risk factor, not only for pulmonary diseases and cancers, but for cardiovascular health. However, the evidence regarding the association between air pollution and acute cardiac events, such as out-of-hospital cardiac arrest (OHCA), is inconsistent, especially at concentrations lower than the WHO daily guideline (25 μg/m³). This study aimed to determine the associations between exposure to ambient air pollution and the incidence of OHCA.

METHODS

In this nationwide case-crossover study, we linked prospectively collected population-based registry data for OHCA in Japan from Jan 1, 2014, to Dec 31, 2015, with daily PM_2·5, carbon monoxide (CO), nitrogen dioxide (NO₂), photochemical oxidants (O_x), and sulphur dioxide (SO₂) exposure on the day of the arrest (lag 0) or 1-3 days before the arrest (lags 1-3), as well as the moving average across days 0-1 and days 0-3. Daily exposure was calculated by averaging the measurements from all PM_2·5 monitoring stations in the same prefecture. The effect of PM_2·5 on risk of all-cause or cardiac OHCA was estimated using a time-stratified case-crossover design coupled with conditional logistic regression analysis, adjusted for daily temperature and relative humidity. Single-pollutant models were also investigated for the individual gaseous pollutants (CO, NO₂, O_x, and SO₂), as well as two-pollutant models for PM_2·5 with these gaseous pollutants. Subgroup analyses were done by sex and age.

FINDINGS

Over the 2 years, 249 372 OHCAs were identified, with 149 838 (60·1%) presumed of cardiac origin. The median daily PM_2·5 was 11·98 μg/m³ (IQR 8·13-17·44). Each 10 μg/m³ increase in PM_2·5 was associated with increased risk of all-cause OHCA on the same day (odds ratio [OR] 1·016, 95% CI 1·009-1·023) and at lags of up to 3 days, ranging from OR 1·015 (1·008-1·022) at lag 1 to 1·033 (1·023-1·043) at lag 0-3. Results for cardiac OHCA were similar (ORs ranging from 1·016 [1·007-1·025] at lags 1 and 2 to 1·034 [1·021-1·047] at lag 0-3). Patients older than 65 years were more susceptible to PM_2·5 exposure than younger age groups but no sex differences were identified. CO, O_x, and SO₂ were also positively associated with OHCA while NO₂ was not. However, in two-pollutant models of PM_2·5 and gaseous pollutants, only PM_2·5 (positive association) and NO₂ (negative association) were independently associated with increased risk of OHCA.

INTERPRETATION

Short-term exposure to PM_2·5 was associated with an increased risk of OHCA even at relatively low concentrations. Regulatory standards and targets need to incorporate the potential health gains from continual air quality improvement even in locations already meeting WHO standards.

FUNDING

None.

The impact of air pollutants on ambulance dispatches: A systematic review and meta-analysis of acute effects

A number of systematic reviews have investigated the association between air pollutants and health impacts, these mostly focus on morbidity and mortality from hospital data. Previously, no reviews focused solely on ambulance dispatch data. These data sets have excellent potential for environmental health research. For this review, publications up to April 2019 were identified using three main search categories covering: ambulance services including dispatches; air pollutants; and health outcomes. From 308 studies initially identified, 275 were excluded as they did not relate to ambulance service dispatches, did not report the air pollutant association, and/or did not study ambient air pollution. The main health outcomes in the remaining 33 studies were cardiac arrest (n = 14), cardiovascular (n = 11) and respiratory (n = 10) dispatches. Meta-analyses were performed to summarise pooled relative risk (RR) of pollutants: particulate matter less than 2.5 and 10 μm (PM_2.5, PM₁₀), the fraction between PM₁₀ and PM_2.5 (coarse) and suspended particulate matter (SPM) per 10 μg/m³ increase, carbon monoxide (CO) per 1 ppm increase and of sulphur dioxide (SO₂), nitrogen dioxide (NO₂), and ozone (O₃) per 10 ppb increment and ambulance dispatches. Statistically significant associations were found for ambulance dispatch data for all-respiratory and PM_2.5 at 1.03 (95% CI:1.02-1.04) and at 1.10 (95% CI:1.00-1.21) for asthma and NO₂ associations. For dispatches with subsequent paramedic assessment for cardiac arrest with PM_2.5, CO and coarse dispatches at 1.05 (95% CI:1.03-1.08), 1.10 (95% CI:1.02-1.18) and 1.04 (95% CI:1.01-1.06) respectively. For dispatches with subsequent physician diagnosis for all-respiratory and PM_2.5 at 1.02 (95% CI:1.01-1.03). In conclusion, air pollution was significantly associated with an increase in ambulance dispatch data, including those for cardiac arrest, all-respiratory, and asthma dispatches. Ambulance services should plan accordingly during pollution events. Furthermore, efforts to improve air quality should lead to decreases in ambulance dispatches.

Identification of long non-coding RNA and circular RNA in mice after intra-tracheal instillation with fine particulate matter

BACKGROUND

Fine particulate matter (PM_2.5) exposure has been proved to be associated with respiratory diseases in epidemiological studies, but the underlying mechanisms are not clear. One of the most important mechanisms involved is inflammation. Non-coding RNAs are proposed to play crucial roles in epigenetic modulation and post-transcriptional regulation. Identification of non-coding RNAs can show us the new insight into the molecular toxicity of PM_2.5.

MATERIALS AND METHODS

Intra-tracheal instillation of saline or PM_2.5 was performed in BALB/c Mice once a week for consecutive eight weeks. Genomewide transcriptome profiling of coding genes, long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) in mice lung were done by ribosomal RNA-depleted RNA sequencing. Lung histological alternations were observed in haematoxylin and eosin (HE) staining sections. The expressions of pro-inflammatory cytokines and Nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome were quantified by qRT-PCR、ELISA and Western blot.

RESULTS

1873 coding genes, 885 lncRNAs and 142 circRNAs were differentially expressed in lung tissues of the saline and PM_2.5 exposed mice. The upregulated expressions of lncRNA NONMMUT065867, lncRNA NONMMUT064312, lncRNA NONMMUT018123 and the downregulated expressions of circRNA CBT15_circR_1011, circRNA mm9_circ_005915 were identified by qRT-PCR in PM_2.5 group. The pulmonary inflammation score was higher in PM_2.5 group. What's more, the expressions of pro-inflammatory cytokines and NLRP3 inflammasome were upregulated in PM_2.5 exposed mice.

CONCLUSION

PM_2.5 causes lung inflammation and increases the expression of NLRP3 inflammasome. The identified novel lncRNAs and circRNAs may paly important role in the development of lung inflammation caused by PM_2.5.

Short-Term Effects of Ambient Air Pollution on ST-Elevation Myocardial Infarction Events: Are There Potentially Susceptible Groups?

Background: Air pollution exposure is associated with greater risk for cardiovascular events. This study aims to examine the effects of increased exposure to short-term air pollutants on ST-segment elevation myocardial infarction (STEMI) and determine the susceptible groups. Methods: Data on particulate matter PM2.5 and PM10 and other air pollutants, measured at each of the 11 air-quality monitoring stations in Kaohsiung City, were collected between 2011 and 2016. The medical records of non-trauma adult (>17 years) patients who had visited the emergency department (ED) with a typical electrocardiogram change of STEMI were extracted. A time-stratified and case-crossover study design was used to examine the relationship between air pollutants and daily ED visits for STEMI. Results: An interquartile range increment in PM2.5 on lag 0 was associated with an increment of 25.5% (95% confidence interval, 2.6%–53.4%) in the risk of STEMI ED visits. Men and persons with ≥3 risk factors (male sex, age, hypertension, diabetes, current smoker, dyslipidemia, history of myocardial infarction, and high body mass index) for myocardial infarction (MI) were more sensitive to the hazardous effects of PM2.5 (interaction: p = 0.039 and p = 0.018, respectively). The associations between PM10, NO2, and O3 and STEMI did not achieve statistical significance. Conclusion: PM2.5 may play an important role in STEMI events on the day of exposure in Kaohsiung. Men and persons with ≥3 risk factors of MI are more susceptible to the adverse effects of PM2.5 on STEMI.

Airborne Particulate Matter: Human Exposure and Health Effects

OBJECTIVE

Exposure to airborne particulate matter (PM) is estimated to cause millions of premature deaths annually. This work conveys known routes of exposure to PM and resultant health effects.

METHODS

A review of available literature.

RESULTS

Estimates for daily PM exposure are provided. Known mechanisms by which insoluble particles are transported and removed from the body are discussed. Biological effects of PM, including immune response, cytotoxicity, and mutagenicity, are reported. Epidemiological studies that outline the systemic health effects of PM are presented.

CONCLUSION

While the integrated, per capita, exposure of PM for a large fraction of the first-world may be less than 1 mg per day, links between several syndromes, including attention deficit hyperactivity disorder (ADHD), autism, loss of cognitive function, anxiety, asthma, chronic obstructive pulmonary disease (COPD), hypertension, stroke, and PM exposure have been suggested. This article reviews and summarizes such links reported in the literature.

Ambient air pollution is associated with pediatric pneumonia: a time-stratified case-crossover study in an urban area

BACKGROUND

Pneumonia, the leading reason underlying childhood deaths, may be triggered or exacerbated by air pollution. To date, only a few studies have examined the association of air pollution with emergency department (ED) visits for pediatric pneumonia, with inconsistent results. Therefore, we aimed to elucidate the impact of short-term exposure to particulate matter (PM) and other air pollutants on the incidence of ED visits for pediatric pneumonia.

METHODS

PM_2.5, PM₁₀, and other air pollutant levels were measured at 11 air quality-monitoring stations in Kaohsiung City, Taiwan, between 2008 and 2014. Further, we extracted the medical records of non-trauma patients aged ≤17 years and who had visited an ED with the principal diagnosis of pneumonia. A time-stratified case-crossover study design was employed to determine the hazard effect of air pollution in a total of 4024 patients.

RESULTS

The single-pollutant model suggested that per interquartile range increment in PM_2.5, PM₁₀, nitrogen dioxide (NO₂), and sulfur dioxide (SO₂) on 3 days before the event increased the odds of pediatric pneumonia by 14.0% [95% confidence interval (CI), 5.1-23.8%], 10.9% (95% CI, 2.4-20.0%), 14.1% (95% CI, 5.0-24.1%), and 4.5% (95% CI, 0.8-8.4%), respectively. In two-pollutant models, PM_2.5 and NO₂ were significant after adjusting for PM₁₀ and SO₂. Subgroup analyses showed that older children (aged ≥4 years) were more susceptible to PM_2.5 (interaction p = 0.024) and children were more susceptible to NO₂ during warm days (≥26.5 °C, interaction p = 0.011).

CONCLUSIONS

Short-term exposure to PM_2.5 and NO₂ possibly plays an important role in pediatric pneumonia in Kaohsiung, Taiwan. Older children are more susceptible to PM_2.5, and all children are more susceptible to NO₂ during warm days.

Out-of-hospital cardiac arrests in a large metropolitan area: synergistic effect of exposure to air particulates and high temperature

Aims

Air pollution and climate change are intrinsically linked to emerging hazards for global health. High air particulate matter (PM) levels may trigger out-of-hospital cardiac arrest (OHCA). High temperature could act synergistically with PM in determining OHCA. The aim of the present study was to investigate the effect of PM exposure alone, and in combination with temperature, on the risk of OHCA, in a large European metropolitan area with population >4 million.

Methods

We evaluated the association between short-term PM exposure, temperature, and the risk of OHCA over a two-year study period, allowing us to investigate 5761 events using a time-stratified case-crossover design combined with a distributed lag non-linear model.

Results

Higher risk of OHCA was associated with short-term exposure to PM10. The strongest association was experienced three days before the cardiac event where the estimated change in risk was 1.70% (0.48–2.93%) per 10 µg/m3 of PM. The cumulative exposure risk over the lags 0–6 was 8.5% (0.0–17.9%). We observed a joint effect of PM and temperature in triggering cardiac arrests, with a maximum effect of 14.9% (10.0–20.0%) increase, for high levels of PM before the cardiac event, in the presence of high temperature.

Conclusion

The present study helps to clarify the controversial role of PM as OHCA determinant. It also highlights the role of increased temperature as a key factor in triggering cardiac events. This evidence suggests that tackling both air pollution and climate change might have a relevant impact in terms of public health.

Ozone and cardiac arrest: The role of previous hospitalizations

BACKGROUND

Several studies have reported associations between exposure to particulate matter and incidence of out-of-hospital cardiac arrest (OHCA) and some have observed associations with ozone (O₃). There are no studies investigating susceptibility based on previous disease history to short-term O₃ exposure and the risk of OHCA.

AIM

To investigate the role of previous cardiovascular-related hospitalizations in modifying the associations between the risk of OHCA and short-term increase in O₃ concentrations.

METHODS

A time-stratified case-crossover analysis of 11,923 OHCA registered in the Swedish Register for Cardiopulmonary Resuscitation from 2006 to 2014 was performed. Using personal identification numbers, OHCA were linked to all previous hospitalizations in Sweden since 1987 to create susceptible groups based on the principal diagnosis code at discharge. Susceptibility was based on hospitalization for i) acute myocardial infarction; ii) heart failure; iii) arrhythmias; iv) diabetes; v) hypertension; and vi) stroke. Moving 2 and 24-h averages for O₃, PM_2.5, PM₁₀, and NO₂ were constructed from hourly averages.

RESULTS

A 10 μg/m³ higher 2-h average O₃ concentration was associated with a 2% higher risk of OHCA (95% CI, 0% 3%). Associations were similar for 24-h average O₃ and in individuals with or without hospitalizations for AMI, heart failure, diabetes, hypertension or stroke. Individuals with previous hospitalizations for arrhythmias had a lower risk of OHCA with higher O₃. No associations were observed for other pollutants.

CONCLUSIONS

Short-term exposure to O₃ was associated with an elevated risk of OHCA, however, previous hospitalizations for cardiovascular diseases were not associated with additionally augmented risks.

Air pollutants and atmospheric pressure increased risk of ED visit for spontaneous pneumothorax

OBJECTIVE

To investigate the impact of short-term exposure to air pollutants and meteorological variation on ED visits for primary spontaneous pneumothorax (PSP).

MATERIAL AND METHODS

We retrospectively identified PSP cases that presented at the ED of our tertiary center between January 2015 and September 2016. We classified the days into three types: no PSP day (0 case/day), sporadic days (1-2 cases/day), and cluster days (PSP, ≥3 cases/day). Association between the daily incidence of PSP with air pollutants and meteorological data were determined using Poisson generalized-linear-model to calculate incidence rate ratio (IRRs) and the use of time-series (lag-1 [the cumulative air pollution level on the previous day of PSP], lag-2 [two days ago], and lag-3 [three days ago]).

RESULTS

Using multivariate logistic regression analysis, O₃ (p = 0.010), NO₂ (p = 0.047), particulate matters (PM)₁₀ (p = 0.021), and PM_2.5 (p = 0.008) were significant factors of PSP occurrence. When the concentration of O₃, NO₂, PM₁₀, and PM_2.5 were increased, PSP IRRs increased approximately 15, 16, 3, and 5-fold, respectively. With the time-series analyses, atmospheric pressure in lag-3 was significantly lower and in lag-2, was significantly higher in PSP days compared with no PSP days. Among air pollutant concentrations, O₃ in lag-1 (p = 0.017) and lag-2 (p = 0.038), NO₂ in lag-1 (p = 0.015) and lag-2 (p = 0.009), PM₁₀ in lag-1 (p = 0.012), and PM_2.5 in lag-1 (p = 0.021) and lag-2 (p = 0.032) were significantly different between no PSP and PSP days.

CONCLUSION

Increased concentrations of air pollutants and abrupt change in atmospheric pressure were significantly associated with increased IRR of PSP.

Long-Term Coarse Particulate Matter Exposure Is Associated with Asthma among Children in Medicaid

RATIONALE

Short- and long-term fine particulate matter (particulate matter ≤2.5 μm in aerodynamic diameter [PM2.5]) pollution is associated with asthma development and morbidity, but there are few data on the effects of long-term exposure to coarse PM (PM10-2.5) on respiratory health.

OBJECTIVES

To understand the relationship between long-term fine and coarse PM exposure and asthma prevalence and morbidity among children.

METHODS

A semiparametric regression model that incorporated PM2.5 and PM10 monitor data and geographic characteristics was developed to predict 2-year average PM2.5 and PM10-2.5 exposure during the period 2009 to 2010 at the zip-code tabulation area level. Data from 7,810,025 children aged 5 to 20 years enrolled in Medicaid from 2009 to 2010 were used in a log-linear regression model with predicted PM levels to estimate the association between PM exposure and asthma prevalence and morbidity, adjusting for race/ethnicity, sex, age, area-level urbanicity, poverty, education, and unmeasured spatial confounding.

MEASUREMENTS AND MAIN RESULTS

Exposure to coarse PM was associated with increased asthma diagnosis prevalence (rate ratio [RR] for 1-μg/m3 increase in coarse PM level, 1.006; 95% confidence interval [CI], 1.001-1.011), hospitalizations (RR, 1.023; 95% CI, 1.003-1.042), and emergency department visits (RR, 1.017; 95% CI, 1.001-1.033) when adjusting for fine PM. Fine PM exposure was more strongly associated with increased asthma prevalence and morbidity than coarse PM. The estimates remained elevated across different levels of spatial confounding adjustment.

CONCLUSIONS

Among children enrolled in Medicaid, exposure to higher average coarse PM levels is associated with increased asthma prevalence and morbidity. These results suggest the need for direct monitoring of coarse PM and reconsideration of limits on long-term average coarse PM pollution levels.

Ultrafine particulate matter impairs mitochondrial redox homeostasis and activates phosphatidylinositol 3-kinase mediated DNA damage responses in lymphocytes

Particulate matter (PM), broadly defined as coarse (2.5-10 μm), fine (0.1-2.5 μm) and ultrafine particles (≤0.1 μm), is a major constituent of ambient air pollution. Recent studies have linked PM exposure (coarse and fine particles) with several human diseases including cancer. However, the molecular mechanisms underlying ultrafine PM exposure induced cellular and sub-cellular repercussions are ill-defined. Since mitochondria are one of the major targets of different environmental pollutants, we herein aimed to understand the molecular repercussion of ultrafine PM exposure on mitochondrial machinery in peripheral blood lymphocytes. Upon comparative analysis, a significantly higher DCF fluorescence was observed in ultrafine PM exposed cells that confirmed the strong pro-oxidant nature of these particles. In addition, the depleted activity of antioxidant enzymes, glutathione reductase and superoxide dismutase suggested the strong association of ultrafine PM with oxidative stress. These results further coincided with mitochondrial membrane depolarization, altered mitochondrial respiratory chain enzyme activity and decline in mtDNA copy number. Moreover, the higher accumulation of DNA damage response proteins (γH2AX, pATM, p-p53), suggested that exposure to ultrafine PM induces DNA damage and triggers phosphatidylinositol 3 kinase mediated response pathway. Further, the alterations in mitochondrial machinery and redox balance among ultrafine PM exposed cells were accompanied by a considerably elevated pro-inflammatory cytokine response. Interestingly, the lower apoptosis levels observed in ultrafine particle treated cells suggest the possibility that the marked alterations may lead to the impairment of mitochondrial-nuclear cross talk. Together, our results showed that ultrafine PM, because of their smaller size possesses significant ability to disturb mitochondrial redox homeostasis and activates phosphatidylinositol 3 kinase mediated DNA damage response pathway, an unknown molecular paradigm of ultrafine PM exposure. Our findings also indicate that maneuvering through the mitochondrial function might be a viable, indirect method to modulate lymphocyte homeostasis in air pollution associated immune disorders.