Associations Between Air Quality Changes and Biomarkers of Systemic Inflammation During the 2014 Nanjing Youth Olympics: A Quasi-Experimental Study

Low-level ambient ozone exposure associated with neutrophil extracellular traps and pro-atherothrombotic biomarkers in healthy adults

BACKGROUND AND AIMS

Uncertainty of the causality determinations for ambient ozone (O3) on cardiovascular events is heightened by the limited understanding of the mechanisms involved in humans. We aimed to examine the pro-atherothrombotic impacts of O3 exposure and to explore the potential mediating roles of dysfunctional neutrophils, focusing on neutrophil extracellular traps (NETs).

METHODS

A longitudinal panel study of 152 healthy adults was conducted in the cool to cold months with relatively low levels of O3 between September 2019 and January 2020 in Beijing, China. Four repeated measurements of indicators reflecting atherothrombotic balance and NETs were performed for each participant.

RESULTS

Daily average exposure levels of ambient O3 were 16.6 μg/m3 throughout the study period. Per interquartile range increase in average concentrations of O3 exposure at prior up to 7 days, we observed elevations of 200.1-276.3% in D-dimer, 27.2-36.8% in thrombin-antithrombin complex, 10.8-60.3% in plasminogen activator inhibitor 1, 13.9-21.8% in soluble P-selectin, 16.5-45.1% in matrix metalloproteinase-8, and 2.4-12.4% in lipoprotein-associated phospholipase A2. These pro-atherothrombotic changes were accompanied by endothelial activation, lung injury, and immune inflammation. O3 exposure was also positively associated with circulating NETs indicators, including citrullinated histone H3, neutrophil elastase, myeloperoxidase, and double-stranded DNA. Mediation analyses indicated that NETs could mediate O3-associated pro-atherothrombotic responses. The observational associations remained significant and robust after controlling for other pollutants, and were generally greater in participants with low levels of physical activity.

CONCLUSIONS

Ambient O3 exposure was associated with significant increases in NETs and pro-atherothrombotic potential, even at exposure levels well below current air quality guidelines of the World Health Organization.

Association between Ambient Particulate Air Pollution and Soluble Biomarkers of Endothelial Function: A Meta-Analysis

BACKGROUND

The burden of cardiovascular diseases caused by ambient particulate air pollution is universal. An increasing number of studies have investigated the potential effects of exposure to particulate air pollution on endothelial function, which is one of the important mechanisms for the onset and development of cardiovascular disease. However, no previous study has conducted a summary analysis of the potential effects of particulate air pollution on endothelial function.

OBJECTIVES

To summarize the evidence for the potential effects of short-term exposure to ambient particulate air pollution on endothelial function based on existing studies.

METHODS

A systematic literature search on the relationship between ambient particulate air pollution and biomarkers of endothelial function including endothelin-1 (ET-1), E-selectin, intercellular cell adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) was conducted in PubMed, Scopus, EMBASE, and Web of Science up to 20 May 2023. Subsequently, a meta-analysis was conducted using a random effects model.

RESULTS

A total of 18 studies were included in this meta-analysis. A 10 μg/m3 increase in short-term exposure to ambient PM2.5 was associated with a 1.55% (95% CI: 0.89%, 2.22%) increase in ICAM-1 and a 1.97% (95% CI: 0.86%, 3.08%) increase in VCAM-1. The associations of ET-1 (0.22%, 95% CI: -4.94%, 5.65%) and E-selectin (3.21%, 95% CI: -0.90% 7.49%) with short-term exposure to ambient PM2.5 were statistically insignificant.

CONCLUSION

Short-term exposure to ambient PM2.5 pollution may significantly increase the levels of typical markers of endothelial function, including ICAM-1 and VCAM-1, suggesting potential endothelial dysfunction following ambient air pollution exposure.

Association between long-term exposure to ambient particulate matter and blood pressure, hypertension: an updated systematic review and meta-analysis

Evidence of more recent studies should be updated to evaluate the effect of long-term exposure to particulate matter (PM) on blood pressure and hypertension.        Studies of long-term effects of PM₁, PM_2.5 and PM₁₀ on blood pressure (SBP, DBP, MAP), hypertension were searched in Pubmed, Web of Science and Embase before May, 2021. Meta-analysis of 41 studies showed that exposure to PM₁, PM_2.5 was associated with SBP (1.76 mmHg (95%CI:0.71, 2.80) and 0.63 mmHg (95%CI:0.40, 0.85), per 10 μg/m³ increase in PM), all three air pollutants (PM₁, PM_2.5, PM₁₀) was associated with DBP (1.16 mmHg (95%CI:0.34, 1.99), 0.31 mmHg (95%CI:0.16, 0.47), 1.17 mmHg (95%CI:0.24, 2.09), respectively. As for hypertension, PM₁, PM_2.5 and PM₁₀ were all significantly associated with higher risk of hypertension (OR=1.27 (95%CI:1.06, 1.52), 1.15 (95%CI:1.10, 1.20) and 1.11 (95%CI:1.07, 1.16). In conclusion, our study indicated a positive association between long-term exposure to particulate matter and increased blood pressure, hypertension.

Associations of fine particulate matter and its metal constituents with blood pressure: A panel study during the seventh World Military Games

Evidence is needed to elucidate the association of blood pressure (BP) changes with metal constituents in fine particulate matter (PM_2.5). Therefore, we designed a longitudinal panel study enrolling 70 healthy students from Wuhan University in the context of the seventh World Military Games (the 7th WMG) from September 2019 to January 2020. A total of eight visits were conducted before, during, and after the 7th WMG. During every visit, each participant was asked to carry a personal PM_2.5 monitor to measure hourly PM_2.5 levels for three consecutive days. Questionnaire investigation and physical examination were completed on the fourth day. We analyzed ten metal constituents of ambient PM_2.5 collected from the fixed station, and blood pressure was recorded during each visit. The linear mixed-effects models were performed to evaluate associations of metal constituents and blood pressure measurements. We observed a dramatic variation of PM_2.5 concentration ranging from 7.38 to 132.04 μg/m³. A 10 μg/m³ increment of PM_2.5 was associated with an increase of 0.64 mmHg (95% CI: 0.44, 0.84) in systolic BP (SBP), 0.40 mmHg (0.26, 0.54) in diastolic BP (DBP), 0.31 mmHg (0.15, 0.47) in pulse pressure (PP) and 0.44 mmHg (0.26, 0.62) in mean artery pressure (MAP), respectively. For metal constituents in PM_2.5, robust positive associations were observed between BP and selenium, manganese, arsenic, cadmium, and thallium. For example, for an IQR (0.93 ng/m³) increment of selenium, SBP and MAP elevated by 0.98 mmHg (0.09, 1.87) and 0.71 mmHg (0.03, 1.39), respectively. Aluminum was found to be robustly associated with decreased SBP, DBP, and MAP. The study indicated that exposure to PM_2.5 total mass and metal constituents including selenium, manganese, arsenic, cadmium, and thallium were associated with the elevated BP.

Overview of particulate air pollution and human health in China: Evidence, challenges, and opportunities

Ambient particulate matter (PM) pollution in China continues to be a major public health challenge. With the release of the new WHO air quality guidelines in 2021, there is an urgent need for China to contemplate a revision of air quality standards (AQS). In the recent decade, there has been an increase in epidemiological studies on PM in China. A comprehensive evaluation of such epidemiological evidence among the Chinese population is central for revision of the AQS in China and in other developing countries with similar air pollution problems. We thus conducted a systematic review on the epidemiological literature of PM published in the recent decade. In summary, we identified the following: (1) short-term and long-term PM exposure increase mortality and morbidity risk without a discernible threshold, suggesting the necessity for continuous improvement in air quality; (2) the magnitude of long-term associations with mortality observed in China are comparable with those in developed countries, whereas the magnitude of short-term associations are appreciably smaller; (3) governmental clean air policies and personalized mitigation measures are potentially effective in protecting public and individual health, but need to be validated using mortality or morbidity outcomes; (4) particles of smaller size range and those originating from fossil fuel combustion appear to show larger relative health risks; and (5) molecular epidemiological studies provide evidence for the biological plausibility and mechanisms underlying the hazardous effects of PM. This updated review may serve as an epidemiological basis for China’s AQS revision and proposes several perspectives in designing future health studies.

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Acute effects of PM are smaller in China compared with developed countries

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Health effects caused by PM depend on particle composition, source, and size

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There are no thresholds for the health effects of PM

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Mechanistic studies support the biological plausibility of PM’s health effects

Urinary CC16, a potential indicator of lung integrity and inflammation, increases in children after short-term exposure to PM2.5/PM10 and is driven by the CC16 38GG genotype

Particular matter (PM) exposure is a big hazard for public health, especially for children. Serum CC16 is a well-known biomarker of respiratory health. Urinary CC16 (U-CC16) can be a noninvasive alternative, albeit requiring adequate adjustment for renal handling. Moreover, the SNP CC16 G38A influences CC16 levels. This study aimed to monitor the effect of short-term PM exposure on CC16 levels, measured noninvasively in schoolchildren, using an integrative approach. We used a selection of urine and buccal DNA samples from 86 children stored in an existing biobank. Using a multiple reaction monitoring method, we measured U-CC16, as well as RBP4 (retinol binding protein 4) and β2M (beta-2-microglobulin), required for adjustment. Buccal DNA samples were used for CC16 G38A genotyping. Linear mixed-effects models were used to find relevant associations between U-CC16 and previously obtained data from recent daily PM ≤ 2.5 or 10 μm exposure (PM_2.5, PM₁₀) modeled at the child's residence. Our study showed that exposure to low PM at the child's residence (median levels 18.9 μg/m³ (PM_2.5) and 23.6 μg/m³ (PM₁₀)) one day before sampling had an effect on the covariates-adjusted U-CC16 levels. This effect was dependent on the CC16 G38A genotype, due to its strong interaction with the association between PM levels and covariates-adjusted U-CC16 (P = 0.024 (PM_2.5); P = 0.061 (PM₁₀)). Only children carrying the 38GG genotype showed an increase of covariates-adjusted U-CC16, measured 24h after exposure, with increasing PM_2.5 and PM₁₀ (β = 0.332; 95% CI: 0.110 to 0.554 and β = 0.372; 95% CI: 0.101 to 0.643, respectively). To the best of our knowledge, this is the first study using an integrative approach to investigate short-term PM exposure of children, using urine to detect early signs of pulmonary damage, and taking into account important determinants such as the genetic background and adequate adjustment of the measured biomarker in urine.

Registered human trials addressing environmental and occupational toxicant exposures: Scoping review of immunological markers and protective strategies

Exposure to pollution is a worldwide societal challenge participating in the etiology and progression of different diseases. However, the scarce information hinders our understanding of the actual level of human exposure and its specific effects. Inadequate and excessive immune responses underlie diverse chronic diseases. Yet, it is unclear which and how toxicant exposures affect the immune system functions. There is a multiplicity of immunological outcomes and biomarkers being studied in human trials related to exposure to different toxicants but still without clear evidence of their value as biomarkers of exposure or effect. The main aim of this study was to collect scientific evidence and identify relevant immunological biomarkers used at the clinical level for toxicant exposures. We used the platform clinical trials.gov as a database tool. First, we performed a search combining research items related to toxicants and immunological parameters. The resulting117 clinical trials were examined for immune-related outcomes and specific biomarkers evaluated in subjects exposed to occupational and environmental toxicants. After categorization, relevant immunological outcomes and biomarkers were identified related to systemic and airway inflammation, modulation of immune cells, allergy and autoimmunity. In general, the immune markers related to inflammation are more frequently investigated for exposure to pollutants, namely IL-6, C-reactive protein (CRP) and nitric oxide (NO). Nevertheless, the data also indicated that prospective biomarkers of effect are gaining ground and a guiding representation of the established and novel biomarkers is suggested for upcoming trials. Finally, potential protective strategies to mitigate the adverse effects of specific toxicants are underlined for future studies.

Long-term exposure to ozone and cardiovascular mortality in China: a nationwide cohort study

BACKGROUND

The evidence for a causal relationship between long-term ozone exposure and cardiovascular mortality is inconclusive, and most published data are from high-income countries. We aimed to investigate the association between long-term exposure to ozone and cardiovascular mortality in China, the most populous middle-income country.

METHODS

We did a nationwide cohort study comprising Chinese adults aged 18 years and older from the 2010-11 China Chronic Disease and Risk Factors Surveillance project; participants were followed up until Dec 31, 2018, or the date of death. Data on participants' deaths were obtained through linkage to the Disease Surveillance Point system, a national death registration database. Residential ozone exposure was estimated with a previously developed random forest model. We applied stratified Cox proportional hazards models to estimate the associations of ozone with mortality due to overall cardiovascular diseases, ischaemic heart disease, and stroke. The models were stratified by age and sex and adjusted for a set of individual-level and regional covariates. Warm-season average ozone concentration for the previous 1-3 years was added as a time-varying variable. We also did subgroup analyses by age, sex, level of education, smoking status, urban or rural residence, and geographical region.

FINDINGS

Data were analysed for 96 955 participants. The warm-season average ozone concentration during the follow-up period was 89·7 μg/m³ (SD 14·4). In the fully adjusted models, we observed significant and positive associations between ozone and mortality from overall cardiovascular diseases (hazard ratio [HR] 1·093 [95% CI 1·046-1·142] per 10 μg/m³ increase in warm-season ozone concentrations), ischaemic heart disease (1·184 [1·099-1·276] per 10 μg/m³ increase in warm-season ozone concentrations), and stroke (1·063 [1·002- 1·128] per 10 μg/m³ increase in warm-season ozone concentrations). After adjusting for fine particulate matter, the associations with overall cardiovascular disease and ischaemic heart disease mortality were almost unchanged, whereas the association with stroke mortality lost statistical significance. The association of long-term ozone exposure with cardiovascular mortality was more prominent in people aged 65 years and older than in those younger than 65 years. We did not find any effect modification of sex, level of education, smoking status, urban or rural residence, and geographical region. We observed an almost linear exposure-response relationship between ozone and cardiovascular mortality.

INTERPRETATION

This study is, to the best of our knowledge, the first nationwide cohort study to show that long-term ozone exposure contributes to elevated risks of cardiovascular mortality, particularly from ischaemic heart disease, in a middle-income setting. The exposure-response function generated from this study could potentially inform future air quality standard revisions and environmental health impact assessments.

FUNDING

National Natural Science Foundation of China.

Ozone exposure and prothrombosis: Mechanistic insights from a randomized controlled exposure trial

Epidemiological studies have associated ozone exposure with cardiovascular diseases, but the molecular mechanisms were not elucidated. We performed an untargeted serum proteomic analysis in a randomized, crossover, controlled exposure trial. We recruited 32 healthy young adults and asked them to receive filtered air and 200-ppb ozone exposures for 2 h in a random order before serum collection. Linear mixed-effect models were used to identify differentially expressed proteins (DEPs) between the two exposures and Gene Ontology enrichment and ingenuity pathway analysis were performed to determine their biological function. A total of 56 DEPs were identified. For example, acute ozone exposure increased coagulation factor X and factor VII-activating protease by 20.96% and 28.35%, respectively. Whereas, protein Z, protein Z-dependent protease inhibitor, and plasminogen decreased by 13.62%, 33.54%, and 10.47%, respectively. We also observed a 42.32% decrease in paraoxonase 3 and evident changes in four apolipoproteins. Additionally, we found 18.21% and 95.82% increases in L-selectin and β2-microglobulin, respectively, and significant changes in three complements. DEPs and enriched pathways suggest that short-term ozone exposure may promote coagulation, suppress fibrinolysis, disrupt lipoprotein metabolism, activate immune responses, and affect the complement system. These findings provide additional insights into the mechanisms linking acute ozone exposure to thrombosis.

Association between gaseous air pollutants and biomarkers of systemic inflammation: A systematic review and meta-analysis

BACKGROUND

Studies have linked gaseous air pollutants to multiple health effects via inflammatory pathways. Several major inflammatory biomarkers, including C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) have also been considered as predictors of cardiovascular disease. However, there has been no meta-analysis to evaluate the associations between gaseous air pollutants and these typical biomarkers of inflammation to date.

OBJECTIVES

To evaluate the overall associations between short-term and long-term exposures to ambient ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), carbon dioxide (CO) and major inflammatory biomarkers including CRP, fibrinogen, IL-6 and TNF-α.

METHODS

A meta-analysis was conducted for publications from PubMed, Web of Science, Scopus and EMBASE databases up to Feb 1st, 2021.

RESULTS

The meta-analysis included 38 studies conducted among 210,438 participants. Generally, we only observed significant positive associations between short-term exposures to gaseous air pollutants and inflammatory biomarkers. For a 10 μg/m³ increase in short-term exposure to O₃, NO₂, and SO₂, there were significant increases of 1.05% (95%CI: 0.09%, 2.02%), 1.60% (95%CI: 0.49%, 2.72%), and 10.44% (95%CI: 4.20%, 17.05%) in CRP, respectively. Meanwhile, a 10 μg/m³ increase in NO₂ was also associated with a 4.85% (95%CI: 1.10%, 8.73%) increase in TNF-α. Long-term exposures to gaseous air pollutants were not statistically associated with these biomarkers, but the study numbers were relatively small. Subgroup analyses found more apparent associations in studies with better study design, higher quality, and smaller sample size. Meanwhile, the associations also varied across studies conducted in different geographical regions.

CONCLUSION

Short-term exposure to gaseous air pollutants is associated with increased levels of circulating inflammatory biomarkers, suggesting that a systemic inflammatory state is activated upon exposure. More studies on long-term exposure to gaseous air pollutants and inflammatory biomarkers are warranted to verify the associations.

Acute Effects of Personal Ozone Exposure on Biomarkers of Inflammation, Oxidative Stress, and Mitochondrial Oxidative Damage - Shanghai Municipality, China, May-October 2016

What is already known on this topic?

It remains inconclusive whether short-term ozone exposure can cause an inflammatory response and oxidative damage in the circulatory system, particularly at low concentrations.

What is added by this report?

This study made an accurate exposure assessment by conducting personal ozone monitoring, thus minimizing the exposure misclassification commonly found in previous environmental epidemiological studies. Our study found that even short-term exposure to low concentrations of ozone was associated with inflammation, lipid peroxidation, and mitochondrial oxidative damage.

What are the implications for public health practice?

Short-term exposure to low concentrations of ozone can still lead to subclinical cardiovascular effects, suggesting the current air quality standards for ozone need to be further tightened in China.

Urinary metabolites of polycyclic aromatic hydrocarbons after short-term fine particulate matter exposure: A randomized crossover trial of air filtration

Research on the relationship between short-term exposure to fine particulate matter (PM_2.5) and urinary metabolites of polycyclic aromatic hydrocarbons (PAHs) is sparse in the nonoccupationally exposed populations. A quasi-experimental observation of haze events nested within a randomized crossover trial of alternative 1-week real or sham indoor air filtration was conducted to evaluate the associations of urinary monohydroxy-PAHs (OH-PAHs) with short-term exposure to PM_2.5 and PM_2.5-bound PAHs. The study was conducted among 57 healthy college students in Beijing, China. PM_2.5-bound PAHs and urinary OH-PAHs were quantified using gas chromatography coupled with a triple-quadrupole tandem mass spectrometer. Linear mixed-effect models were applied to evaluate the association of urinary OH-PAHs with time-weighted personal PM_2.5 and PM_2.5-bound PAHs, controlling for potentially confounding variables. The results demonstrated that air filtration could markedly reduce external exposure to PM_2.5 and PM_2.5-bound parent, nitrated, and oxygenated PAHs. In the intervention trial, the urinary concentrations of 2-hydroxyfluorene (2-OH-FLU) and 9-hydroxyphenanthrene (9-OH-PHE) were elevated significantly by 16.5% (95% CI, 2.1%, 33.1%) and 37.9% (95% CI, 8.4%, 75.4%), respectively, in association with a doubling increase in personal PM_2.5 exposure. Urinary 9-OH-PHE was also significantly positively associated with the increase in the sum of PM_2.5-bound parent PAHs. Furthermore, the levels of urinary OH-PAHs such as 2-OH-FLU and 9-OH-PHE in the haze events were elevated by 31.1% (95% CI, 8.7%, 53.4%) and 73.5% (95% CI, 16.0%, 131.0%), respectively, in association with a doubling increase in personal PM_2.5 exposure. The findings indicated that urinary 2-OH-FLU and 9-OH-PHE could serve as potential internal exposure biomarkers for assessing short-term PM_2.5 exposure in nonoccupational populations.

Short-Term Effects of Particle Sizes and Constituents on Blood Biomarkers among Healthy Young Adults in Guangzhou, China

Evidence of the effects of various particle sizes and constituents on blood biomarkers is limited. We performed a panel study with five repeated measurements in 88 healthy college students in Guangzhou, China between December 2017 and January 2018. Mass concentrations of particles with aerodynamic diameters ≤ 2.5 μm (PM_2.5), PM₁, and PM_0.5 and number concentrations of particles with aerodynamic diameters ≤ 200 nm (PN_0.2) and PN_0.1 were measured. We used linear mixed-effect models to explore the associations of size-fractionated particulate matter and PM_2.5 constituents with five blood biomarkers 0-5 days prior to blood collection. We found that an interquartile range (45.9 μg/m³) increase in PM_2.5 concentration was significantly associated with increments of 16.6, 3.4, 12.3, and 8.8% in C-reactive protein (CRP), monocyte chemoattractant protein-1 (MCP-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and endothelin-1(ET-1) at a 5-day lag, respectively. Similar estimates were observed for PM₁, PM_0.5, PN_0.2, and PN_0.1. For PM_2.5 constituents, consistent positive associations were observed between F^- and sVCAM-1 and CRP and between NH₄⁺ and MCP-1, and negative associations were found between Na⁺ and MCP-1 and ET-1, between Cl^- and MCP-1, and between Mg²⁺ and sVCAM-1. Our results suggested that both particle size and constituent exposure are significantly associated with circulating biomarkers among healthy Chinese adults. Particularly, PN_0.1 at a 5-day lag and F^- and NH₄⁺ are the most associated with these blood biomarkers.

The acute effects of short term exposure to particulate matter from natural and anthropogenic sources on inflammation and coagulation markers in healthy young adults

Airborne particulate matter is associated with increasing the risk of cardiovascular diseases. The purpose of this study was to investigate the association between air pollution conditions and MDA, vWF, and fibrinogen markers in the blood of two panels of healthy young individuals in an urban area in Tehran city with a high air pollution background and another group was living in a rural area (Ahmad Abad Mostofi), with a low air pollution background. In each group, 4 blood samples were taken as follows: one in inversion days, the second in winter, but during the existence of normal condition in terms of air pollution, the third sample in the spring during the normal condition in terms of air pollution and the fourth sample during the dust storm conditions. In the urban and rural groups, there was a significant difference between the concentration of MDA, vWF, fibrinogen between inversion and cold season control conditions, and between dust storm conditions and warm season control conditions (p < 0.05). The results showed that the association of dust storm condition on the measured biomarkers was stronger than the inversion condition, which health consideration in the dust conditions be taken into account similar to the inversion conditions.

Inflammatory and oxidative stress responses of healthy adults to changes in personal air pollutant exposure

Exposure to air pollutants has been associated with respiratory and cardiovascular mortality, but the underlying molecular mechanisms remain inadequately understood. We aimed to examine molecular-level inflammatory and oxidative stress responses to personal air pollutant exposure. Fifty-three healthy adults aged 22-52 were measured three times for their blood inflammatory cytokines and urinary malondialdehyde (MDA, an oxidative stress biomarker) within 2 consecutive months. Pollutant concentrations monitored indoors and outdoors were combined with the time-activity data to calculate personal O₃, PM_2.5, NO₂, and SO₂ exposures averaged over 12 h, 24 h, 1 week, and 2 weeks, respectively, prior to biospecimen collection. Inflammatory cytokines and MDA were associated with pollutant exposures using linear mixed-effects models controlling for various covariates. After adjusting for a co-pollutant, we found that concentrations of proinflammatory cytokines were significantly and negatively associated with 12-h O₃ exposures and significantly but positively associated with 2-week O₃ exposures. We also found significant and positive associations of proinflammatory cytokines with 12-h and 24-h NO₂ exposures, respectively. However, we did not find clear associations of PM_2.5 and SO₂ exposure with proinflammatory cytokines and with MDA. The removal of an O₃-generating electrostatic precipitator in the mechanical ventilation systems of the offices and residences of the subjects was associated with significant decreases in IL-1β, IL-2, IL-6, IL-8, IL-17A, and TNF-α. These findings suggest that exposure to O₃ for different time durations may affect systemic inflammatory responses in different ways.

Cardiorespiratory responses to fine particles during ambient PM2.5 pollution waves: Findings from a randomized crossover trial in young healthy adults

BACKGROUND

PM_2.5 pollution waves (PPWs) are severe air pollution events with extremely high-level concentration of ambient PM_2.5. PPWs, such as haze days, were suggested to be associated with increased cardiopulmonary mortality and morbidity. However, the biological mechanism response to ambient PM_2.5 during PPWs is still unclear.

METHODS

A randomized crossover trial was conducted on 29 healthy young adults. Repeated health measurements were performed before, during and after two typical PPWs under filtered and sham indoor air purification, with a washout interval of at least 2 weeks. Health parameters including blood pressure (BP), pulmonary function, fractional exhaled nitric oxide (FeNO) and circulating biomarkers which reflect platelet activation, blood coagulation and systematic oxidative stress were measured.

RESULTS

Ambient PM_2.5 levels elevated apparently during PPWs. Under sham purification, significant increase in FeNO and soluble P-selectin (sP-selectin) and decreases in pulmonary function were observed from pre-PPWs period to during-PPWs period. The changes in health biomarkers as mentioned above became attenuated and insignificant under filtered condition. For instance, sP-selectin increased by 12.0% (95% CI: 3.8%, 20.8%) during-PPWs periods compared with pre-PPWs periods under sham purification, while non-significant change was observed under filtered condition. Significant associations between time-weighted personal PM_2.5 exposure and increased levels of health biomarkers including FeNO, sP-selectin, oxidized low-density lipoprotein (ox-LDL) and 8-isoprostane (8-isoPGF2α) were found.

CONCLUSION

PPWs could affect cardiopulmonary health through systematic oxidative stress, platelet activation and respiratory inflammation in healthy adults, and short-term indoor air purification could alleviate the adverse cardiopulmonary effects.

The association between long-term fine particulate air pollution and life expectancy in China, 2013 to 2017

BACKGROUND

China is experiencing one of the worst air quality problems in the world. China implemented the Air Pollution Prevention and Control Action Plan (APPCAP) and the air quality has recently achieved remarkable improvement.

OBJECTIVE

To evaluate the associations of variations in annual fine particulate matter (PM_2.5) levels and changes in life expectancy in Chinese urban populations from 2013 to 2017.

METHOD

We collected annual-average concentrations of PM_2.5 and average life expectancy of urban residents in 214 cities from 2013 to 2017. We conducted a longitudinal panel analysis applying linear mixed-effect models to evaluate the association between PM_2.5 reduction and life expectancy increase with and without adjustment for socioeconomic and medical-care confounders.

RESULT

The nationwide-average annual PM_2.5 concentrations decreased from 67.78 μg/m³ in 2013 to 45.25 μg/m³ in 2017; meanwhile, the average life expectancy of urban residents increased from 78.53 to 79.86 years. A decrease of 10 μg/m³ in PM_2.5 was associated with an increment of 0.18 (95% confidence interval: 0.06, 0.30) year in life expectancy. After simultaneously adjusting for GDP per capita, smoking prevalence, urbanization rate and maternal mortality, the association turned to be insignificant at the national level, but remained significant in the eastern region with life expectancy gained 0.16 (95% CI: 0.04, 0.27) year per 10 μg/m³ reduction of PM_2.5.

CONCLUSION

Lower PM_2.5 air pollution might be associated with extended life expectancy in east of China. The implementation of APPCAP during 2013 to 2017 might have resulted in benefits on life expectancy, especially in east of China.

Precision multiparameter tracking of inflammation on timescales of hours to years using serial dried blood spots

Aim: High-frequency longitudinal tracking of inflammation using dried blood microsamples provides a new window for personalized monitoring of infections, chronic inflammatory disease and clinical trials of anti-inflammatory drugs. Results/methodology: Using 1662 dried blood spot samples collected by 16 subjects over periods of weeks to years, we studied the behavior of 12 acute phase response and related proteins in inflammation events correlated with infection, vaccination, surgery, intense exercise and Crohn's disease. Proteins were measured using SISCAPA mass spectrometry and normalized to constant plasma volume using low-variance proteins, generating high precision within-person biomarker trajectories with well-characterized personal baselines. Discussion/conclusion: The results shed new light on the dynamic regulation of APR responses, offering a new approach to visualization of multidimensional inflammation trajectories.

Short-term exposure to ambient air pollution and circulating biomarkers of endothelial cell activation: The Framingham Heart Study

BACKGROUND

Short-term exposure to air pollution has been associated with cardiovascular events, potentially by promoting endothelial cell activation and inflammation. A few large-scale studies have examined the associations and have had mixed results.

METHODS

We included 3820 non-current smoking participants (mean age 56 years, 54% women) from the Framingham Offspring cohort examinations 7 (1998-2001) and 8 (2005-2008), and Third Generation cohort examination 1 (2002-2005), who lived within 50 km of a central monitoring station. We calculated the 1- to 7-day moving averages of fine particulate matter (PM_2.5), black carbon (BC), sulfate (SO₄^2-), nitrogen oxides (NO_x), and ozone before examination visits. We used linear mixed effect models for P-selectin, monocyte chemoattractant protein 1 (MCP-1), intercellular adhesion molecule 1, lipoprotein-associated phospholipase A2 activity and mass, and osteoprotegerin that were measured up to twice, and linear regression models for CD40 ligand and interleukin-18 that were measured once, adjusting for demographics, life style and clinical factors, socioeconomic position, time, and meteorology.

RESULTS

We found negative associations of PM_2.5 and BC with P-selectin, of ozone with MCP-1, and of SO₄^2- and NO_x with osteoprotegerin. At the 5-day moving average, a 5 µg/m³ higher PM_2.5 was associated with 1.6% (95% CI: - 2.8, - 0.3) lower levels of P-selectin; a 10 ppb higher ozone was associated with 1.7% (95% CI: - 3.2, - 0.1) lower levels of MCP-1; and a 20 ppb higher NO_x was associated with 2.0% (95% CI: - 3.6, - 0.4) lower levels of osteoprotegerin.

CONCLUSIONS

We did not find evidence of positive associations between short-term air pollution exposure and endothelial cell activation. On the contrary, short-term exposure to higher levels of ambient pollutants were associated with lower levels of P-selectin, MCP-1, and osteoprotegerin in the Framingham Heart Study.

Association between ambient air pollution and pregnancy rate in women who underwent IVF

STUDY QUESTION

Are the concentrations of five criteria air pollutants associated with probabilities of biochemical pregnancy loss and intrauterine pregnancy in women?

SUMMARY ANSWER

Increased concentrations of ambient particulate matter (PM10), nitrogen dioxide (NO2), carbon monoxide (CO) during controlled ovarian stimulation (COS) and after embryo transfer were associated with a decreased probability of intrauterine pregnancy.

WHAT IS KNOWN ALREADY

Exposure to high ambient air pollution was suggested to be associated with low fertility and high early pregnancy loss in women.

STUDY DESIGN, SIZE, DURATION

Using a retrospective cohort study design, we analysed 6621 cycles of 4581 patients who underwent one or more fresh IVF cycles at a fertility centre from January 2006 to December 2014, and lived in Seoul at the time of IVF treatment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

To estimate patients' individual exposure to air pollution, we computed averages of hourly concentrations of five air pollutants including PM10, NO2, CO, sulphur dioxide (SO2) and ozone (O3) measured at 40 regulatory monitoring sites in Seoul for each of the four exposure periods: period 1 (start of COS to oocyte retrieval), period 2 (oocyte retrieval to embryo transfer), period 3 (embryo transfer to hCG test), and period 4 (start of COS to hCG test). Hazard ratios (HRs) from the time-varying Cox-proportional hazards model were used to estimate probabilities of biochemical pregnancy loss and intrauterine pregnancy for an interquartile range (IQR) increase in each air pollutant concentration during each period, after adjusting for individual characteristics. We tested the robustness of the result using generalised linear mixed model, accounting for within-woman correlation.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean age of the women was 35 years. Average BMI was 20.9 kg/m2 and the study population underwent 1.4 IVF cycles on average. Cumulative pregnancy rate in multiple IVF cycles was 51.3% per person. Survival analysis showed that air pollution during periods 1 and 3 was generally associated with IVF outcomes. Increased NO2 (adjusted HR = 0.93, 95% CI: 0.87, 0.99) and CO (0.94, 95% CI: 0.89, 1.00) during period 1 were associated with decreased probability of intrauterine pregnancy. PM10 (0.92, 95% CI: 0.85, 0.99), NO2 (0.93, 95% CI = 0.86, 1.00) and CO (0.93, 95% CI: 0.87, 1.00) levels during period 3 were also inversely associated with intrauterine pregnancy. Both PM10 (1.17, 95% CI: 1.04 1.33) and NO2 (1.18, 95% CI: 1.03, 1.34) during period 3 showed positive associations with biochemical pregnancy loss.

LIMITATIONS, REASONS FOR CAUTION

The district-specific ambient air pollution treated as an individual exposure may not represent the actual level of each woman's exposure to air pollution. Smoking, working status, parity or gravidity of women, and semen analysis data were not included in the analysis.

WIDER IMPLICATIONS OF THE FINDINGS

This study provided evidence of an association between increased ambient concentrations of PM10, NO2 and CO and reduced probabilities for achieving intrauterine pregnancy using multiple IVF cycle data. Specifically, our results indicated that lower intrauterine pregnancy rates in IVF cycles may be linked to ambient air pollution during COS and the post-transfer period.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013 R1A6A3A04059017, 2016 R1D1A1B03933410 and 2018 R1A2B6004608) and the National Cancer Center of Korea (NCC-1810220-01). The authors report no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Quantitative Analysis of Health Risk Perception, Exposure Levels, and Willingness to Pay/Accept of PM2.5 during the 2014 Nanjing Youth Olympic Games

Local governments in China regularly implement short-term emission control measures to improve air quality during important sporting events. As a condition for hosting the 2014 Youth Olympic Games (YOG), the Nanjing government agreed to temporarily and substantially improve air quality. Regression analysis, Spearman correlation analysis, χ² test, and the contingent valuation method were used to explore the effects of robust, short-term air pollution control measures on risk perception, daily exposure to PM_2.5, risk acceptance levels, and willingness to pay/accept (WTP/WTA) for reductions in air pollution for the benefit of reducing health risks. Postimplementation, the respondents' risk perception levels presented the following changes: during the YOG, the respondents perceived the lowest effects of haze pollution while after the YOG, they perceived the highest effects. The changes in risk acceptance levels showed the same tendency. Furthermore, after the YOG, the respondents asked for the most economic compensation, and their willingness to pay for risk reduction also reached the highest level. This study reveals the need to increase the public's understanding of the health risks of air pollution, protect those populations most exposed to high levels of PM_2.5, and take more effective long-term measures to meet local residents' demands for improved air quality.