Short-term increase in particulate matter blunts nocturnal blood pressure dipping and daytime urinary sodium excretion

Impact of PM2.5, relative humidity, and temperature on sleep quality: a cross-sectional study in Taipei

INTRODUCTION

TWe investigated impacts of particulate matter with an aerodynamic diameter of less than 2.5 μm (PM2.5), relative humidity (RH), and temperature on sleep stages and arousal.

MATERIALS AND METHODS

A cross-sectional analysis involving 8,611 participants was conducted at a sleep center in Taipei. We estimated individual-level exposure to RH, temperature, and PM2.5 over 1-day, 7-day, and 30-day periods. Linear regression models assessed the relationship between these environmental factors and sleep parameters across different seasons. Mediation analysis was used to explore PM2.5, RH, and temperature roles in these relationships.

RESULTS

A 1% increase in RH over 1 and 7 days was associated with changes in non-rapid eye movement (NREM) sleep stages and increases in the arousal index across all seasons. A 1°C increase in temperature over similar periods led to increases in rapid eye movement (REM) sleep. During cold season, changes in RH and temperature were linked to variations in arousal and NREM sleep stages. In hot season, RH and temperature increases were correlated with changes in NREM sleep stages and arousal. Across all groups, a 1-μg/m³ increase in PM2.5 levels was associated with alterations in NREM and REM sleep stages and increases in the arousal index. We found PM2.5 levels mediated relationships between RH, temperature, and various sleep stages, particularly in cold season.

CONCLUSIONS

Lower RH and temperature, contributing to deep sleep reduction and increased arousal, were influenced by elevated PM2.5 exposure, especially during colder months. Enhancing environmental quality and reducing PM2.5 levels may lead to improved sleep quality.

Joint effects of temperature and humidity with PM2.5 on COPD

BACKGROUND

Particulate matter less than 2.5 microns in aerodynamic diameter (PM2.5) is a significant air pollutant known to adversely affect respiratory health and increase the incidence of chronic obstructive pulmonary disease (COPD). Furthermore, climate change exacerbates these impacts, as extreme temperatures and relative humidity (RH) levels can intensify the effects of PM2.5. This study aims to examine the joint effects of PM2.5, temperature, and RH on the risk of COPD.

METHODS

A case-control study was conducted among 1,828 participants from 2017 to 2022 (995 COPD patients and 833 controls). The radial basis function interpolation was utilized to estimate participants' individual mean and differences in PM2.5, temperature, and RH in 1-day, 7-day, and 1-month periods. Logistic regression models examined the associations of environmental exposures with the risk of COPD adjusting for confounders. Joint effects of PM2.5 by quartiles of temperature and RH were also examined.

RESULTS

We observed that a 1 µg/m3 increase in PM2.5 7-day and 1-month mean was associated with a 1.05-fold and 1.06-fold increase in OR of COPD (p < 0.05). For temperature and RH, we observed U-shaped effects on OR for COPD with optimal temperatures identified as 21.2 °C, 23.8 °C, and 23.8 °C for 1-day, 7-day, and 1-month mean temperature, respectively, and optimal RH levels identified as 73.8%, 76.7%, and 75.4% for 1-day, 7-day, and 1-month mean RH, respectively (p < 0.05). The joint effect models show that high temperatures (> 23.5 °C) and both extremely low (69.3%) and high (80.9%) RH levels generally exacerbate the effects of PM2.5 on OR for COPD, especially over longer exposure durations.

CONCLUSION

The joint effects of PM2.5, temperature, and RH on the risk of COPD underscore the importance of air pollution control and comprehensive research to mitigate COPD risk in the context of climate change.

Impact of Wildfire Smoke on Acute Illness

Climate change increases wildfire smoke exposure. Inhaled smoke causes inflammation, oxidative stress, and coagulation, which exacerbate cardiovascular and respiratory disease while worsening obstetric and neonatal outcomes.

Association between PM2.5 constituents and cardiometabolic risk factors: Exploring individual and combined effects, and mediating inflammation

BACKGROUND

The individual and combined effects of PM2.5 constituents on cardiometabolic risk factors are sparsely investigated. Besides, the key cardiometabolic risk factor that PM2.5 constituents targeted and the biological mechanisms remain unclear.

METHOD

A multistage, stratified cluster sampling survey was conducted in two typically air-polluted Chinese cities. The PM2.5 and its constituents including sulfate, nitrate, ammonium, organic matter, and black carbon were predicted using a machine learning model. Twenty biomarkers in three category were simultaneously adopted as cardiometabolic risk factors. We explored the individual and mixture association of long-term PM2.5 constituents with these markers using generalized additive model and quantile-based g-computation, respectively. To minimize potential confounding effects, we accounted for covariates including demographic, lifestyle, meteorological, temporal trends, and disease-related information. We further used ROC curve and mediation analysis to identify the key subclinical indicators and explore whether inflammatory mediators mediate such association, respectively.

RESULT

PM2.5 constituents was positively correlated with HOMA-B, TC, TG, LDL-C and LCI, and negatively correlated with PP and RC. Further, PM2.5 constituent mixture was positive associated with DBP, MAP, HbA1c, HOMA-B, AC, CRI-1 and CRI-2, and negative associated with PP and HDL-C. The ROC analysis further reveals that multiple cardiometabolic risk factors can collectively discriminate exposure to PM2.5 constituents (AUC>0.9), among which PP and CRI-2 as individual indicators exhibit better identifiable performance for nitrate and ammonium (AUC>0.75). We also found that multiple blood lipid indicators may be affected by PM2.5 and its constituents, possibly mediated through complement C3 or hsCRP.

CONCLUSION

Our study suggested associations of individual and combined PM2.5 constituents exposure with cardiometabolic risk factors. PP and CRI-2 were the targeted markers of long-term exposure to nitrate and ammonium. Inflammation may serve as a mediating factor between PM2.5 constituents and dyslipidemia, which enhance current understanding of potential pathways for PM2.5-induced preclinical cardiovascular responses.

Particulate matter deposition and its impact on tuberculosis severity: A cross-sectional study in Taipei

The objective of this study was to examine the association between the lung lobe-deposited dose of inhaled fine particulate matter (PM2.5) and chest X-ray abnormalities in different lung lobes of pulmonary tuberculosis (TB), multidrug-resistant tuberculosis (MDR-TB), and non-tuberculosis mycobacteria infections (NTM). A cross-sectional study was conducted between 2014 and 2022, comprising 1073 patients who were recruited from chest department clinic in a tertial refer hospital in Taipei City, Taiwan. Ambient 1-, 7-, and 30-day PM2.5 exposure and the deposition of PM2.5 in different lung lobes were estimated in each subject. The β coefficient for PM2.5 and deposited PM2.5 in lungs with the outcome variables (pulmonary TB, MDR-TB, and NTM infection) was derived through regression analysis and adjusted for age, gender, BMI, smoking status, and family income. We observed that a 1 μg/m3 increase in ambient PM2.5 was associated with an increase of MDR-TB infections of 0.004 times (95%CI: 0.001-0.007). A 1 μg/m3 increase in 1-day and 7-day PM2.5 deposition in left upper lobe and left lower lobe was associated with an increase in chest X-ray abnormalities of 9.19 % and 1.18 % (95%CI: 0.87-17.51 and 95%CI: 0.08-2.28), and 4.52 % and 5.20 % (95%CI: 0.66-8.38 and 95%CI: 0.51-9.89) in left lung of TB patients, respectively. A 1 μg/m3 increase in 30-day PM2.5 deposition in alveolar region was associated with an increase in percent abnormality of 2.50 % (95%CI: 0.65-4.35) in left upper lobe and 3.33 % (95%CI: 0.65-6.01) in right middle lobe, while in total lung was 0.63 % (95%CI: 0.01-1.27) in right upper lobe and 0.37 % (95%CI, 0.06-0.81) in right lung of MDR-TB patients. Inhaled PM2.5 deposition in lungs was associated with an exacerbation of the radiographic severity of pulmonary TB, particularly in pulmonary MDR-TB patients in upper and middle lobes. Particulate air pollution may potentially exacerbate the radiographic severity and treatment resistance in individuals with pulmonary TB.

Effects of occupational exposure to metal fume PM2.5 on lung function and biomarkers among shipyard workers: a 3-year prospective cohort study

OBJECTIVE

This study investigates the associations of α1-antitrypsin, inter-α-trypsin inhibitor heavy chain (ITIH4), and 8-isoprostane with lung function in shipyard workers exposed to occupational metal fume fine particulate matter (PM2.5), which is known to be associated with adverse respiratory outcomes.

METHODS

A 3-year follow-up study was conducted on 180 shipyard workers with 262 measurements. Personal exposure to welding fume PM2.5 was collected for an 8-h working day. Pre-exposure, post-exposure, and delta (∆) levels of α1-antitrypsin, ITIH4, and 8-isoprostane were determined in urine using enzyme-linked immunosorbent assays. Post-exposure urinary metals were sampled at the beginning of the next working day and analyzed by inductively coupled plasma-mass spectrometry. Lung function measurements were also conducted the next working day for post-exposure.

RESULTS

An IQR increase in PM2.5 was associated with decreases of 2.157% in FEV1, 2.806% in PEF, 4.328% in FEF25%, 5.047% in FEF50%, and 7.205% in FEF75%. An IQR increase in PM2.5 led to increases of 42.155 µg/g in ∆α1-antitrypsin and 16.273 µg/g in ∆ITIH4. Notably, IQR increases in various urinary metals were associated with increases in specific biomarkers, such as post-urinary α1-antitrypsin and ITIH4. Moreover, increases in ∆ α1-antitrypsin and ∆ITIH4 were associated with decreases in FEV1/FVC by 0.008% and 0.020%, respectively, and an increase in ∆8-isoprostane resulted in a 1.538% decline in FVC.

CONCLUSION

Our study suggests that urinary α1-antitrypsin and ITIH4 could indicate early lung function decline in shipyard workers exposed to metal fume PM2.5, underscoring the need for better safety and health monitoring to reduce respiratory risks.

Different Impacts of Traffic-Related Air Pollution on Early-Onset and Late-Onset Asthma

Background

Early-onset asthma (EOA) and late-onset asthma (LOA) are two distinct phenotypes. Air pollution has been associated with an increase in poorer asthma outcomes. The objective of this study was to examine the effects of traffic-related air pollution (TRAP) on asthma outcomes in EOA and LOA patients.

Methods

A cross-sectional study was conducted on 675 asthma patients (LOA: 415) recruited from a major medical center in Taiwan. The land-use regression (LUR) model was used to estimate the level of exposure to PM10, PM2.5, NO2, and O3 on an individual level. We investigated the association between TRAP and asthma outcomes in EOA and LOA patients, stratified by allergic sensitization status, using a regression approach.

Results

An increase in PM10 was associated with younger age of onset, increased asthma duration, and decreased lung function in EOA patients (p<0.05). An increase in PM10 was associated with older age of onset, and decreased asthma duration, eosinophil count, and Asthma Control Test (ACT) score in LOA patients. An increase in PM2.5 was associated with younger age of onset, increased asthma duration, decreased eosinophil count, and lung function in EOA patients (p<0.05). An increase in PM2.5 was associated with decreased lung function and ACT score in LOA patients. An increase in NO2 was associated with increased eosinophil count and decreased lung function in EOA patients (p<0.05). An increase in O3 was associated with decreased lung function in LOA patients (p<0.05). In addition, associations of TRAP with age of onset and eosinophil counts were mainly observed in both EOA and LOA patients with allergic sensitization, and an association with ACT was mainly observed in LOA patients without allergic sensitization.

Conclusion

The impact of TRAP on age of onset, eosinophil count, and lung function in EOA patients, and ACT in LOA patients, was affected by the status of allergic sensitization.

Short-term mediating effects of PM2.5 on climate-associated COPD severity

The impact of short-term exposure to environmental factors such as temperature, relative humidity (RH), and fine particulate matter (PM2.5) on chronic obstructive pulmonary disease (COPD) remains unclear. The objective of this study is to investigate PM2.5 as a mediator in the relationship between short-term variations in RH and temperature and COPD severity. A cross-sectional study was conducted on 930 COPD patients in Taiwan from 2017 to 2022. Lung function, COPD Assessment Test (CAT) score, and modified Medical Research Council (mMRC) dyspnea scale were assessed. The mean and differences in 1-day, 7-day, and 30-day individual-level exposure to ambient RH, temperature, and PM2.5 were estimated. The associations between these factors and clinical outcomes were analyzed using linear regression models and generalized additive mixed models, adjusting for age, sex, smoking, and body mass index. In the total season, increases in RH difference were associated with increases in forced expiratory volume in 1 s (FEV1) / forced vital capacity (FVC), while increases in temperature difference were associated with decreases in FEV1 and FEV1/FVC. Increases in PM2.5 mean were associated with declines in FEV1. In the cold season, increases in temperature mean were associated with decreases in CAT and mMRC scores, while increases in PM2.5 mean were associated with declines in FEV1, FVC, and FEV1/FVC. In the warm season, increases in temperature difference were associated with decreases in FEV1 and FEV1/FVC, while increases in RH difference and PM2.5 mean were associated with decreases in CAT score. PM2.5 fully mediated the associations of temperature mean with FEV1/FVC in the cold season. In conclusion, PM2.5 mediates the effects of temperature and RH on clinical outcomes. Monitoring patients during low RH, extreme temperature, and high PM2.5 levels is crucial. Capsule of findings The significance of this study is that an increase in ambient RH and temperature, as well as PM2.5 exposure, were significantly associated with changes in lung function, and clinical symptoms in these patients. The novelty of this study is that PM2.5 plays a mediating role in the association of RH and temperature with COPD clinical outcomes in the short term.

Prediction value of neutrophil and eosinophil count at risk of COPD exacerbation

INTRODUCTION

Predicting acute exacerbations (AEs) in chronic obstructive pulmonary disease (COPD) is crucial. This study aimed to identify blood biomarkers for predicting COPD exacerbations by inflammatory phenotypes.

MATERIALS AND METHODS

We analyzed blood cell counts and clinical outcomes in 340 COPD patients aged 20-90 years. Patients were categorized into eosinophilic inflammation (EOCOPD) and non-eosinophilic inflammation (N-EOCOPD) groups. Blood cell counts, eosinophil-to-lymphocyte ratio (ELR), neutrophil-to-lymphocyte ratio (NLR) and neutrophil-to-eosinophil ratio (NER) were calculated. Linear and logistic regression models assessed relationships between health outcomes and blood cell counts.

RESULTS

EOCOPD patients had distinct characteristics compared to N-EOCOPD patients. Increased neutrophil % and decreased lymphocyte % were associated with reduced pulmonary function, worse quality of life and more exacerbations, but they did not show statistical significance after adjusting by age, sex, BMI, smoking status, FEV1% and patient's medication. Subgroup analysis revealed a 1.372-fold increase in the OR of AE for every 1 unit increase in NLR in EOCOPD patients (p < .05). In N-EOCOPD patients, every 1% increase in blood eosinophil decreased the risk of exacerbation by 59.6%.

CONCLUSIONS

Our study indicates that distinct white blood cell profiles in COPD patients, with or without eosinophilic inflammation, can help assess the risk of AE in clinical settings.

Association of joint exposure to various ambient air pollutants during adolescence with blood pressure in young adulthood

The association of various air pollutants exposure during adolescence with blood pressure (BP) in young adulthood is uncertain. We intended to evaluate the long-term association of individual and joint air pollutants exposure during adolescence with BP in young adulthood. This cross-sectional study of incoming students was conducted in five geographically disperse universities in China during September and October 2018. Mean concentrations of particulate matter with diameters ≤2.5 μm (PM2.5 ), ≤10 μm (PM10 ), nitrogen dioxides (NO2 ), carbon monoxide (CO), sulfur dioxide (SO2 ), and ozone (O3 ) at participants' residential addresses during 2013-2018 were collected from the Chinese Air Quality Reanalysis dataset. Generalized linear mixed models (GLM) and quantile g-computation (QgC) models were utilized to estimate the association between individual and joint air pollutants exposure and systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP). A total of 16,242 participants were included in the analysis. The GLM analyses showed that PM2.5 , PM10 , NO2 , CO, and SO2 were significantly positively associated with SBP and PP, while O3 was positively associated with DBP. The QgC analyses indicated that long-term exposure to a mixture of the six air pollutants had a significant positive joint association with SBP and PP. In conclusion, air pollutant co-exposure during adolescence may influence BP in young adulthood. The findings of this study emphasized the impacts of multiple air pollutants interactions on potential health and the need of minimizing pollution exposures in the environment.

Fine particulate matter (PM2.5)-induced pulmonary oxidative stress contributes to increases in glucose intolerance and insulin resistance in a mouse model of circadian dyssynchrony

Results of human and animal studies independently suggest that either ambient fine particulate matter (PM2.5) air pollution exposure or a disturbed circadian rhythm (circadian dyssynchrony) are important contributing factors to the rapidly evolving type-2-diabetes (T2D) epidemic. The objective of this study is to investigate whether circadian dyssynchrony increases the susceptibility to PM2.5 and how PM2.5 affects metabolic health in circadian dyssynchrony. We examined systemic and organ-specific changes in glucose homeostasis and insulin sensitivity in mice maintained on a regular (12/12 h light/dark) or disrupted (18/6 h light/dark, light-induced circadian dyssynchrony, LICD) light cycle exposed to air or concentrated PM2.5 (CAP, 6 h/day, 30 days). Exposures during Zeitgeber ZT3-9 or ZT11-17 (Zeitgeber in circadian time, ZT0 = begin of light cycle) tested for time-of-day PM2.5 sensitivity (chronotoxicity). Mice transgenic for lung-specific overexpression of extracellular superoxide dismutase (ecSOD-Tg) were used to assess the contribution of CAP-induced pulmonary oxidative stress. Both, CAP exposure from ZT3-9 or ZT11-17, decreased glucose tolerance and insulin sensitivity in male mice with LICD, but not in female mice or in mice kept on a regular light cycle. Although changes in glucose homeostasis in CAP-exposed male mice with LICD were not associated with obesity, they were accompanied by white adipose tissue (WAT) inflammation, impaired insulin signaling in skeletal muscle and liver, and systemic and pulmonary oxidative stress. Preventing CAP-induced oxidative stress in the lungs mitigated the CAP-induced decrease in glucose tolerance and insulin sensitivity in LICD. Our results demonstrate that circadian dyssynchrony is a novel susceptibility state for PM2.5 and suggest that PM2.5 by inducing pulmonary oxidative stress increases glucose intolerance and insulin resistance in circadian dyssynchrony.

Alleviating air pollutant-associated hypertension by potassium intake in Korean adults: a cross-sectional study from the 2012-2016 Korea National Health and Nutrition Examination Survey

Air pollution may increase the risk of hypertension (HTN) by increasing oxidative stress and inflammation, and reducing sodium excretion. Potassium intake may reduce the risk of HTN through sodium excretion and reduce inflammation and oxidative stress. This study is aimed at investigating the association between air pollutants and HTN and whether these associations differ based on the potassium intake data of Korean adults from the 2012-2016 Korean National Health and Nutrition Examination Survey (KNHANES). This cross-sectional study used data from KNHANES (2012-2016) combined with annual air pollutant data from the Ministry of Environment using administrative units. We included 15,373 adults who responded to the semi-food frequency questionnaire. Associations between ambient PM₁₀, SO₂, NO₂, CO, and O₃ with HTN according to potassium intake were assessed using the survey logistic regression model for complex samples analysis. After adjusting for potential covariates such as, age, sex, education level, smoking status, family income, alcohol consumption, body mass index (BMI), exercise status, and survey year, as the air pollutant score considering the five air pollutants increased (severe air pollution), the prevalence of HTN increased in a dose-dependent manner (p for trend < 0.001). Meanwhile, in the adults with higher potassium intake and who were exposed to lowest levels of air pollutants score (score = 0), the ORs of HTN were significantly lower (OR = 0.56, 95% CI: 0.32-0.97). In conclusion, our study suggests that exposure to air pollutants may increase the prevalence of HTN among Korean adults. However, high potassium intake may help prevent HTN caused by air pollutants.

Investigating the association between ambient particulate matter (PM10) exposure and blood pressure values: Results from the link between the Portuguese Health Examination Survey and air quality data

INTRODUCTION AND OBJECTIVES

High blood pressure (BP) remains a major modifiable cardiovascular (CV) risk factor. Several epidemiologic studies have been performed to assess the association between air pollution exposure and this CV risk factor but results remain inconsistent. This study aims to estimate the effect of short-term PM₁₀ exposure (average previous three-day concentration) on diastolic (DBP) and systolic (SBP) blood pressure values of the resident mainland Portuguese population.

METHODS

Our study was based on available DBP and SBP data from 2272 participants from the first Portuguese Health Examination Survey (INSEF, 2015) living within a 30 km radius of at least one air quality monitoring station, with available measurements of particulate matter with an aerodynamic equivalent diameter ≤10 μm (PM₁₀). We used data from the air quality monitoring network of the Portuguese Environment Agency to obtain the individual allocated PM₁₀ concentrations. Generalized linear models were used to assess the effect of PM₁₀ exposure on DBP and SBP values.

RESULTS

No statistically significant association was found between PM₁₀ exposure and both DBP and SBP values (0.42% DBP change per 10 μg/m³ of PM₁₀ increment (95% confidence interval (CI): -0.85; 1.70) and 0.47% SBP change per 10 μg/m³ of PM₁₀ increment (95% CI: -0.86; 1.79)). Results remain unchanged after restricting the analysis to hypertensive or obese participants or changing the PM₁₀ assessment methodology.

CONCLUSIONS

In view of the PM₁₀ levels observed in 2015, our results suggests that exposure to PM₁₀ concentrations have a small or no effect on the blood pressure values. Other air pollutants and mixtures of pollutants that were not included in our study should considered in future studies.

Ambient relative humidity-dependent obstructive sleep apnea severity in cold season: A case-control study

BACKGROUND

The objective of this study was to examine associations of daily averages and daily variations in ambient relative humidity (RH), temperature, and PM_2.5 on the obstructive sleep apnea (OSA) severity.

METHODS

A case-control study was conducted to retrospectively recruit 8628 subjects in a sleep center between January 2015 and December 2021, including 1307 control (apnea-hypopnea index (AHI) < 5 events/h), 3661 mild-to-moderate OSA (AHI of 5-30 events/h), and 3597 severe OSA subjects (AHI > 30 events/h). A logistic regression was used to examine the odds ratio (OR) of outcome variables (daily mean or difference in RH, temperature, and PM_2.5 for 1, 7, and 30 days) with OSA severity (by the groups). Two-factor logistic regression models were conducted to examine the OR of RH with the daily mean or difference in temperature or PM_2.5 with OSA severity. An exposure-response relationship analysis was conducted to examine the outcome variables with OSA severity in all, cold and warm seasons.

RESULTS

We observed associations of mean PM_2.5 and RH with respective increases of 0.04-0.08 and 0.01-0.03 events/h for the AHI in OSA patients. An increase in the daily difference of 1 % RH increased the AHI by 0.02-0.03 events/h in OSA patients. A daily PM_2.5 decrease of 1 μg/m³ reduced the AHI by 0.03 events/h, whereas a daily decrease in the RH of 1 % reduced the AHI by 0.03-0.04 events/h. The two-factor model confirmed the most robust associations of ambient RH with AHI in OSA patients. The exposure-response relationship in temperature and RH showed obviously seasonal patterns with OSA severity.

CONCLUSION

Short-term ambient variations in RH and PM_2.5 were associated with changes in the AHI in OSA patients, especially RH in cold season. Reducing exposure to high ambient RH and PM_2.5 levels may have protective effects on the AHI in OSA patients.

Associations between air pollutants and blood pressure in an ethnically diverse cohort of adolescents in London, England

Longitudinal evidence on the association between air pollution and blood pressure (BP) in adolescence is scarce. We explored this association in an ethnically diverse cohort of schoolchildren. Sex-stratified, linear random-effects modelling was used to examine how modelled residential exposure to annual average nitrogen dioxide (NO2), particulate matter (PM2.5, PM10) and ozone (O3), measures in μg/m3, associated with blood pressure. Estimates were based on 3,284 adolescents; 80% from ethnic minority groups, recruited from 51 schools, and followed up from 11-13 to 14-16 years old. Ethnic minorities were exposed to higher modelled annual average concentrations of pollution at residential postcode level than their White UK peers. A two-pollutant model (NO2 & PM2.5), adjusted for ethnicity, age, anthropometry, and pubertal status, highlighted associations with systolic, but not diastolic BP. A μg/m3 increase in NO2 was associated with a 0.30 mmHg (95% CI 0.18 to 0.40) decrease in systolic BP for girls and 0.19 mmHg (95% CI 0.07 to 0.31) decrease in systolic BP for boys. In contrast, a 1 μg/m3 increase in PM2.5 was associated with 1.34 mmHg (95% CI 0.85 to 1.82) increase in systolic BP for girls and 0.57 mmHg (95% CI 0.04 to 1.03) increase in systolic BP for boys. Associations did not vary by ethnicity, body size or socio-economic advantage. Associations were robust to adjustments for noise levels and lung function at 11-13 years. In summary, higher ambient levels of NO2 were associated with lower and PM2.5 with higher systolic BP across adolescence, with stronger associations for girls.

The Association between Air Pollutants Exposure with Pre- and Hypertension by Vitamin C Intakes in Korean Adults: A Cross-Sectional Study from the 2013-2016 Korea National Health and Nutrition Examination

OBJECTIVES

Oxidative stress and systemic inflammation are the main pathways by which air pollutants cause hypertension (HTN). Vitamin C intake may reduce the risk of HTN caused by air pollutants. This study aimed to investigate the association between air pollutants and pre-HTN and HTN in Korean adults and whether these associations were modified by vitamin C intake, using data from the 2013-2016 Korean National Health and Nutrition Examination Survey (KNHANES).

DESIGN

Cross-sectional study.

SETTING

This study used data from the KNHANES VI (2013-2015) and VII (2016) along with the data from the annual air pollution report of the Ministry of Environment.

PARTICIPANTS

We included 11,866 adults who had responded to a semi-food frequency questionnaire.

MEASUREMENTS

We used survey logistic regression models to evaluate the association of ambient PM10, SO2, NO2, CO, and O3 with pre-HTN and HTN according to vitamin C intake.

RESULTS

After adjusting for potential covariates, exposure to ambient PM10, SO2, NO2, and CO was significantly associated with a high prevalence of pre-HTN and HTN, whereas exposure to O3 was significantly associated with a low prevalence of pre-HTN and HTN. In particular, as the air pollutant scores increased (severe air pollution), the prevalence of pre-HTN and HTN increased in a dose-dependent manner (highest score vs. lowest score, OR=1.85, 95% CI=1.39-2.46, p for trend <.0001). However, these associations were found to be pronounced in adults with low vitamin C intake (highest score vs. lowest score, OR=2.30, 95% CI=1.50-3.54, p for trend <.0001), whereas the statistical significance disappeared for adults with high vitamin C intake (highest score vs. lowest score, OR=1.40, 95% CI=0.93-2.12, p for trend=0.007).

CONCLUSION

Exposure to air pollutants such as PM10, SO2, NO2, and CO may increase the prevalence of pre-HTN and HTN among Korean adults. In addition, a high intake of vitamin C may help prevent pre-HTN and HTN caused by air pollutants.

Particulate matter 2.5, metropolitan status, and heart failure outcomes in US counties: A nationwide ecologic analysis

The relationship between particulate matter with a diameter of 2.5 micrometers or less (PM2.5) and heart failure (HF) hospitalizations and mortality in the US is unclear. Prior studies are limited to studying the effects of daily PM2.5 exposure on HF hospitalizations in specific geographic regions. Because PM2.5 can vary by geography, this study examines the effects of annual ambient PM2.5 exposure on HF hospitalizations and mortality at a county-level across the US. A cross-sectional analysis of county-level ambient PM2.5 concentration, HF hospitalizations, and HF mortality across 3135 US counties nationwide was performed, adjusting for county-level demographics, socioeconomic factors, comorbidities, and healthcare-associated behaviors. There was a moderate correlation between county PM2.5 and HF hospitalization among Medicare beneficiaries (r = 0.41) and a weak correlation between county PM2.5 and HF mortality (r = 0.08) (p-values < 0.01). After adjustment for various county level covariates, every 1 ug/m3 increase in annual PM2.5 concentration was associated with an increase of 0.51 HF Hospitalizations/1,000 Medicare Beneficiaries and 0.74 HF deaths/100,000 residents (p-values < 0.05). In addition, the relationship between PM2.5 and HF hospitalizations was similar when factoring in metropolitan status of the counties. In conclusion, increased ambient PM2.5 concentration level was associated with increased incidence of HF hospitalizations and mortality at the county level across the US. This calls for future studies exploring policies that reduce ambient particulate matter pollution and their downstream effects on potentially improving HF outcomes.

Climate-mediated air pollution associated with COPD severity

Air pollution has been reported to be associated with chronic obstructive pulmonary disease (COPD). Our study aim was to examine the mediating effects of air pollution on climate-associated health outcomes of COPD patients. A cross-sectional study of 117 COPD patients was conducted in a hospital in Taiwan. We measured the lung function, 6-min walking distance, oxygen desaturation, white blood cell count, and percent emphysema (low attenuation area, LAA) and linked these to 0-1-, 0-3-, and 0-5-year lags of individual-level exposure to relative humidity (RH), temperature, and air pollution. Linear regression models were conducted to examine associations of temperature, RH, and air pollution with severity of health outcomes. A mediation analysis was conducted to examine the mediating effects of air pollution on the associations of RH and temperature with health outcomes. We observed that a 1 % increase in the RH was associated with increases in forced expiratory volume in 1 s (FEV₁), eosinophils, and lymphocytes, and a decrease in the total-lobe LAA. A 1 °C increase in temperature was associated with decreases in oxygen desaturation, and right-, left-, and upper-lobe LAA values. Also, a 1 μg/m³ increase in PM_2.5 was associated with a decrease in the FEV₁ and an increase in oxygen desaturation. A 1 μg/m³ increases in PM₁₀ and PM_2.5 was associated with increases in the total-, right-, left, upper-, and lower-lobe (PM_2.5 only) LAA. A one part per billion increase in NO₂ was associated with a decrease in the FEV₁ and an increase in the upper-lobe LAA. Next, we found that NO₂ fully mediated the association between RH and FEV₁. We found PM_2.5 fully mediated associations of temperature with oxygen saturation and total-, right-, left-, and upper-lobe LAA. In conclusion, climate-mediated air pollution increased the risk of decreasing FEV₁ and oxygen saturation and increasing emphysema severity among COPD patients. Climate change-related air pollution is an important public health issue, especially with regards to respiratory disease.

Redox Regulatory Changes of Circadian Rhythm by the Environmental Risk Factors Traffic Noise and Air Pollution

Significance: Risk factors in the environment such as air pollution and traffic noise contribute to the development of chronic noncommunicable diseases. Recent Advances: Epidemiological data suggest that air pollution and traffic noise are associated with a higher risk for cardiovascular, metabolic, and mental disease, including hypertension, heart failure, myocardial infarction, diabetes, arrhythmia, stroke, neurodegeneration, depression, and anxiety disorders, mainly by activation of stress hormone signaling, inflammation, and oxidative stress. Critical Issues: We here provide an in-depth review on the impact of the environmental risk factors air pollution and traffic noise exposure (components of the external exposome) on cardiovascular health, with special emphasis on the role of environmentally triggered oxidative stress and dysregulation of the circadian clock. Also, a general introduction on the contribution of circadian rhythms to cardiovascular health and disease as well as a detailed mechanistic discussion of redox regulatory pathways of the circadian clock system is provided. Future Directions: Finally, we discuss the potential of preventive strategies or "chrono" therapy for cardioprotection. Antioxid. Redox Signal. 37, 679-703.

Associations of genetic risk factors and air pollution with incident hypertension among participants in the UK Biobank study

The purposes of this study were to quantify the association of the combination of air pollution and genetic risk factors with hypertension and explore the interactions between air pollution and genetic risk. This study included 391,366 participants of European ancestry initially free from pre-existing hypertension in the UK Biobank. Exposure to ambient air pollutants, including particulate matter (PM_2.5 PM_2.5-10, and PM₁₀), nitrogen dioxide (NO₂) and nitrogen oxides (NO_X), was estimated through land use regression modelling, and the associations between air pollutants and the incidence of hypertension were investigated using a Cox proportional hazards model adjusted for covariates. Furthermore, we established a polygenic risk score for hypertension and assessed the combined effect of genetic susceptibility and air pollution on incident hypertension. The results showed significant associations between the risk of hypertension and exposure to PM_2.5 (hazard ratio [HR]: 1.41, 95% confidence interval [CI]: 1.29-1.53; per 10 μg/m³), PM₁₀ (1.05, 1.00-1.09; per 10 μg/m³), and NO_X (1.01, 1.01-1.02 per 10 μg/m³). Additive effects of PM_2.5 and NO_X exposure and genetic risk were observed. Compared to individuals with a low genetic risk and low air pollution exposure, participants with high air pollution exposure and a high genetic risk had a significantly increased risk of hypertension (PM_2.5: 71% (66%-76%), PM₁₀: 59% (55%-64%), NO_X: 65% (60%-70%)). Our results indicate that long-term exposure to air pollution is associated with an increased risk of hypertension, especially in individuals with a high genetic risk.

Air pollution associated with cognitive decline by the mediating effects of sleep cycle disruption and changes in brain structure in adults

The effects of air pollution on sleep and dementia remain unclear. The objective of this study was to investigate the effects of air pollution on cognitive function as mediated by the sleep cycle. A cross-sectional study design was conducted to recruit 4866 subjects on which PSG had been performed. Fifty of them were further given a cognitive function evaluation by the MMSE and CASI as well as brain images by CT and MRI. Associations of 1-year air pollution parameters with sleep parameters, cognitive function, and brain structure were examined. We observed that O3 was associated with a decrease in arousal, an increase in the N1 stage, and a decrease in the N2 stage of sleep. NO2 was associated with an increase in the N1 stage, a decrease in the N2 stage, and an increase in REM. PM2.5 was associated with a decrease in the N1 stage, increases in the N2 and N3 stages, and a decrease in REM. The N1 and N2 stages were associated with cognitive decline, but REM was associated with an increase in cognitive function. The N1 stage was a mediator of the effects of PM2.5 on the concentration domain of the MMSE. O3 was associated with an increase in the pars orbitalis volume of the left brain. NO2 was associated with increases in the rostral middle frontal volume, supramarginal gyrus volume, and transverse temporal volume of the left brain, and the pars opercularis volume of the right brain. PM2.5 was associated with increases in the pars triangularis volume of the left brain and the fusiform thickness of the right brain. In conclusion, we observed that air pollution was associated with cognitive decline by mediating effects on the sleep cycle with changes in the brain structure in controlling executive, learning, and language functions in adults.

The impacts of ambient relative humidity and temperature on supine position-related obstructive sleep apnea in adults

Obstructive sleep apnea (OSA) is associated with seasonal variations. The objective of this study was to examine associations of ambient relative humidity (RH) and temperature on sleep parameters. We conducted a cross-sectional study by retrospectively recruiting 5204 adults from a sleep center in Taipei, Taiwan. Associations of 1-night polysomnography with ambient RH and temperature in 1-day, 7-day, 1-month, 6-month, and 1-year averages were examined using linear regression models and a mediation analysis. RH increase was associated with snoring index decrease and apnea/hypopnea index (AHI) increase. Temperature increase was associated with decreases in sleep efficiency and the AHI, and increases in the wake time after sleep onset and snoring index. RH increase was inversely associated with non-rapid eye movement (NREM) sleep stage I (N1), III (N3), and rapid eye movement (REM) sleep, but positively associated with the NREM sleep stage II (N2) stage. Temperature increase was associated with N1, N2, and N3 sleep. An increase in RH was associated with an increase in the arousal index and a decrease in the < 95% arterial oxygen saturation (SaO₂) among total, REM, and NREM sleep, whereas a temperature increase was associated with a decrease in the arousal index and an increase in < 95% SaO₂ among total, REM, and NREM sleep. An increase in RH was associated with increases in the time spent in a supine posture and the supine AHI. An increase in temperature was associated with decreases in the supine posture, supine AHI, and non-supine AHI. The N3 sleep stage was an important mediator in increasing the supine AHI with a long-term increase in RH. But the N1 and N2 sleep stages mediated a decrease in the supine AHI with an increase in RH. In conclusion, ambient RH and temperature were associated with alterations in sleep parameters in adults, which were mediated by the sleep cycle. An understanding of outdoor environments has important implications for diagnostic classifications in the supine dominance of OSA in adults.

Associations between lung-deposited dose of particulate matter and culture-positive pulmonary tuberculosis pleurisy

Epidemiological studies identified the relationship between air pollution and pulmonary tuberculosis. Effects of lung-deposited dose of particulate matter (PM) on culture-positive pulmonary tuberculosis remain unclear. This study investigates the association between lung-deposited dose of PM and pulmonary tuberculosis pleurisy. A case-control study of subjects undergoing pleural effusion drainage of pulmonary tuberculosis (case) and chronic heart failure (control) was conducted. Metals and biomarkers were quantified in the pleural effusion. The air pollution exposure was measured and PM deposition in the head, tracheobronchial, alveolar region, and total lung region was estimated by Multiple-path Particle Dosimetry (MPPD) Model. We performed multiple logistic regression to examine the associations of these factors with the risk of tuberculosis. We observed that 1-μg/m³ increase in PM₁₀ was associated with 1.226-fold increased crude odds ratio (OR) of tuberculosis (95% confidence interval (CI): 1.023-1.469, p<0.05), 1-μg/m³ increase in PM_2.5-10 was associated with 1.482-fold increased crude OR of tuberculosis (95% CI: 1.048-2.097, p < 0.05), 1-ppb increase in NO₂ was associated with 1.218-fold increased crude OR of tuberculosis (95% CI: 1.025-1.447, p < 0.05), and 1-ppb increase in O₃ was associated with 0.735-fold decreased crude OR of tuberculosis (95% CI: 0.542 0.995). We observed 1-μg/m³ increase in PM deposition in head and nasal region was associated with 1.699-fold increased crude OR of tuberculosis (95% CI: 1.065-2.711, p < 0.05), 1-μg/m³ increase in PM deposition in tracheobronchial region was associated with 1.592-fold increased crude OR of tuberculosis (95% CI: 1.095-2.313, p < 0.05), 1-μg/m³ increase in PM deposition in alveolar region was associated with 3.981-fold increased crude OR of tuberculosis (95% CI: 1.280-12.386, p < 0.05), and 1-μg/m³ increase in PM deposition in total lung was associated with 1.511-fold increased crude OR of tuberculosis (95% CI: 1.050-2.173, p < 0.05). The results indicate that particle deposition in alveolar region could cause higher risk of pulmonary tuberculosis pleurisy than deposition in other lung regions.

The impact of PM2.5 on children's blood pressure growth curves: A prospective cohort study

OBJECTIVE

The aim of this study was to explore the association between exposure to particulate matter with an aerodynamic diameter of 2.5 mm or less (PM2.5) and blood pressure (BP) levels in children and adolescents and to illustrate the impact of PM2.5 levels on BP growth curves in a cohort study.

METHODS

A longitudinal study was designed and included 4303 children (7617 BP measurements) living in the selected areas, and evaluations were conducted in 2014-2015 (visit 1) and followed up in 2019 (visit 2). Two-stage stratified cluster sampling was used to include urban-rural areas. A mixed linear regression model and mixed logistic regression model were used to analyze the effect of PM2.5 exposure on BP and the incidence of prehypertension and hypertension in children.

RESULTS

After adjusting for covariates, systolic blood pressure (SBP) (2.21 (95% CIs: 0. 81, 3.62), mmHg), diastolic blood pressure (DBP) (1.92 (95% CIs: 0.74, 3.11), mmHg), mean arterial pressure (MAP) (2.03 (95% CIs: 0.89, 3.17), mmHg) and heart rate (HR) (2.24 (95% CIs: 0.11, 4.37), beats/min) increased significantly in the fourth quartile of PM2.5 exposure levels compared with the first quartile (all P < 0.01). In addition, long-term exposure to PM2.5 was significantly positively correlated with SBP, DBP and MAP, and the effect was more notable in urban areas than that in rural areas. Moreover, the risk of prehypertension and hypertension incidence increased by 1.17 (95% CIs: 1.03, 1.33) fold with a one-quartile increase in PM2.5 exposure. The long-term effects of annual mean PM2.5 exposure on SBP, DBP and MAP were significant from pregnancy to 7, 3 and 4 years of age, respectively.

CONCLUSION

Long-term exposure to PM2.5 was positively associated with growth curves of hemodynamics indexed from pregnancy to childhood and adolescence, and the effect was more significant in urban areas than in rural areas.

Association of meteorological factors and ambient air pollution on medical care utilization for urolithiasis: a population-based time-series study

BACKGROUND

To identify the association of meteorological factors/ambient air pollutants with medical care utilization for urolithiasis and estimate the effect size/time lags.

METHODS

This is a population-based time-series analysis of 300,000 urolithiasis cases from eight large metropolitan areas in Korea. Seventeen meteorological factors and ambient air pollutants were measured daily during 2002-2017 for each metropolis. Data on daily medical utilization owing to urolithiasis were collected. A generalized additive model was used while factoring in the nonlinear relationship between meteorological factors/ambient air pollutants and urolithiasis and a time lag of ≤10 days. A multivariate analysis was performed. Backward elimination with an Akaike information criterion was used for fitting the multivariate model.

RESULTS

Urolithiasis was significantly associated with average temperature, diurnal temperature range, sunshine duration, particulate matter (PM) ≤2.5 μm, and carbon monoxide (CO) levels. The incidence of ureteral stones was positively correlated with average temperature, PM ≤2.5 μm level, and CO level (time lags 0-9, 2-4, and 0-9 days, respectively). The incidence of renal stones was positively correlated with PM ≤2.5 μm and CO levels (time lags 2-4 and 0-9 days, respectively). PM ≤2.5 μm (0.05 and 0.07% per 10 μg/m³⁾ and CO (2.05 and 2.25% per 0.1 ppm) conferred the highest excess risk on ureteral and renal stones.

CONCLUSIONS

Urolithiasis is affected by various meteorological factors and ambient air pollutants, PM ≤2.5 μm, and CO levels may be novel potential risk factors for this condition.

Short-term associations between particulate matter air pollution and hospital admissions through the emergency room for urinary system disease in Beijing, China: A time-series study

Evidence on the relationship between particulate matter air pollution and urinary system disease (UD) is scarce. This study aims to evaluate the associations between short-term exposures to PM_2.5 and PM₁₀ and risk of daily UD inpatient hospital admissions through the emergency room (ER-admissions) in Beijing. We obtained 41,203 weekday UD ER-admissions for secondary and tertiary hospitals in all 16 districts in Beijing during 2013-2018 from the Beijing Municipal Health Commission Information Center and obtained district-level air pollution concentrations based on 35 fixed monitoring stations in Beijing. We conducted a two-stage time-series analysis, with district-specific generalized linear models for each of Beijing's 16 districts, followed by random effects meta-analysis to obtain pooled risk estimates. We evaluated lagged and cumulative associations up to 30 days. In single-pollutant models, for both PM_2.5 and PM₁₀, cumulative exposure averaged over the day of admission and the previous 10 days (lag 0-10 days) showed the strongest association, with per interquartile range increases of PM_2.5 or PM₁₀ concentrations associated with a 7.5 % (95 % confidence interval [CI]: 3.0 %-12.2 %) or 6.0 % (95 % CI: 1.1 %-11.2 %) increased risk of daily UD hospital admissions, respectively. The risk estimates were robust to adjustment for co-pollutants and to a variety of sensitivity analyses. However, due to the strong correlation between PM_2.5 and PM₁₀ concentrations, we were unable to disentangle the respective relationships between these two exposures and UD risk. In this study, we found that short-term exposures to PM_2.5 and PM₁₀ are risk factors for UD morbidity and that cumulative exposure to PM pollution over a period of one to two weeks (i.e., 11 days) could be more important for UD risk than transient exposure during each of the respective single days.

Impacts of PM2.5 on Ambulatory Blood Pressure Monitoring Indicators Attenuated by Blood Pressure Control Status and Treatment - Two Cities and Two Municipalities, China, 2017-2019

What is already known about this topic?

Short-term PM_2.5 exposure has been associated with hourly, 24-hour, daytime, and nighttime blood pressure (BP) levels, and further studies focusing whether and how the associations with other ambulatory BP monitoring indicators are warranted.

What is added by this report?

This study observed that short-term PM_2.5 exposure was associated with BP elevations and was the first to report the associations of short-term PM_2.5 exposure with BP variability. Circadian rhythm of BP and BP load among hypertensive patients were found to be modified by controlled BP status or taking angiotensin receptor blockers (ARBs).

What are the implications for public health practice?

This study suggested that antihypertensive therapy, especially with well-controlled BP status may be potential measurements to attenuate adverse impacts of PM_2.5 for hypertensive patients with intermediate-to-high risk of cardiovascular disease (CVD).

Association Between Air Pollution and Lung Lobar Emphysema in COPD

The development of emphysema has been linked to air pollution; however, the association of air pollution with the extent of lobar emphysema remains unclear. This study examined the association of particulate matter <2.5 μm in aerodynamic diameters (PM_2.5) (≤2.5 μm), nitrogen dioxide (NO₂), and ozone (O₃) level of exposure with the presence of emphysema in 86 patients with chronic obstructive pulmonary disease (COPD). Exposure to the air pollution estimated using the land-use regression model was associated with lung function, BODE (a body mass index, degree of obstruction, dyspnea severity, and exercise capacity index) quartiles, and emphysema measured as low-attenuation areas on high-resolution CT (HR-CT) lung scans. Using paraseptal emphysema as the reference group, we observed that a 1 ppb increase in O₃ was associated with a 1.798-fold increased crude odds ratio of panlobular emphysema (p < 0.05). We observed that PM_2.5 was associated with BODE quartiles, modified Medical Research Council (mMRC) dyspnea score, and exercise capacity (all p < 0.05). We found that PM_2.5, NO₂, and O₃ were associated with an increased degree of upper lobe emphysema and lower lobe emphysema (all p < 0.05). Furthermore, we observed that an increase in PM_2.5, NO₂, and O₃ was associated with greater increases in upper lobe emphysema than in lower lobe emphysema. In conclusion, exposure to O₃ can be associated with a higher risk of panlobular emphysema than paraseptal emphysema in patients with COPD. Emphysema severity in lung lobes, especially the upper lobes, may be linked to air pollution exposure in COPD.

Spatial analysis of the effects of PM2.5 on hypertension among the middle-aged and elderly people in China

Hypertension is currently one of the most common chronic diseases with high global prevalence associated with a huge social and economic burden. In recent years, air pollution has become a focus of research, especially the effects of PM2.5 on hypertension. However, few studies have considered the spatial properties of the sample; thus, the results might be unreliable. Based on the China Health and Retirement Longitudinal Study (CHARLS) and the Environmental Status Bulletin for each province in China, we used the extended shared component model (SCM) to fit the spatial variation of hypertension risk and to reveal the impact of PM2.5 on hypertension in males and females. Our results revealed that the crude prevalence of hypertension for the whole population in China was 32.74% in 2015, with the prevalence in men experiencing slightly higher than that in women (32.92% vs. 32.58%). We found that the distribution of hypertension prevalence exhibited obvious spatial aggregation for the whole population in China (Moran's I = 0.39, P = 0.001), with similar results in both men (Moran's I = 0.18, P = 0.027) and women (Moran's I = 0.52, P = 0.001). Furthermore, the smoothed results obtained using the SCM indicated that some eastern and central provinces had relatively higher hypertension risk, while the risk in southeastern provinces was much lower. The risk was also relatively lower in most western provinces, except for some northwestern regions. Notably, our results showed that PM2.5 was a risk factor for hypertension, and the impact of PM2.5 on women was slightly greater than that on men, with odds ratios (OR) of 1.063 (1.041, 1.086) and 1.048 (1.025, 1.071), respectively. Our findings suggest the existence of distinct spatial differences in the prevalence of hypertension and small sex-related differences in the risk of hypertension in China.

Chronic exposure to metal fume PM2.5 on inflammation and stress hormone cortisol in shipyard workers: A repeat measurement study

Particulate matter with an aerodynamic diameter of ≤ 2.5 µm (PM_2.5) has been linked to adverse health outcomes in welding workers. The objective of this study was to investigate associations of chronic exposure to metal fume PM_2.5 in shipyard workers with health outcomes. A longitudinal study was conducted to determine the effects of metal fume PM_2.5 on FeNO, urinary metals, urinary oxidative stress, inflammation, and stress hormones in workers. There were 20 office workers and 49 welding workers enrolled in this study who were followed-up for a second year. We observed that Fe, Zn, and Mn were abundant in PM_2.5 to which welding workers were personally exposed, whereas PM_2.5 to which office workers were personally exposed was dominated by Pb, Cu, and Zn. We observed in the first and/or second visits that urinary 8-iso-prostaglandin F2-α (PGF2α) and 8-hydroxy-2'-deoxy guanosine (8-OHdG) were significantly increased by exposure. An increase in urinary interleukin (IL)-6 and decreases in urinary serotonin and cortisol were observed in the first and/or second visits after exposure. PM_2.5 was associated with decreases in urinary 8-OHdG and cortisol among workers. Next, we observed that urinary Ni, Co, and Fe had significantly increased among workers after a year of exposure. Urinary metals were associated with decreases in urinary 8-iso-PGF2α and cortisol among workers. Urinary Ni, Cu, and Fe levels were associated with an increase in urinary IL-6 and a decrease in urinary cortisol among workers. In conclusion, chronic exposure to metal fume PM_2.5 was associated with inflammation and a cortisol deficiency in shipyard workers, which could associate with adrenal glands dysfunction.

Ambient air pollutants aggravate association of snoring with prevalent hypertension: results from the Henan Rural Cohort

AIM

We aimed to assess if snoring and ambient air pollutants were jointly associated with prevalent hypertension in a cross-sectional study.

METHODS

A total of 28440 participants aged 18-79 years were obtained from the Henan Rural Cohort. Snoring evaluated using Pittsburgh sleep quality index (PSQI) scale was classified into 'Never', '<3 times/week' and '≥3 times/week' groups. Concentrations of air pollutants (PM₁, PM_2.5, PM₁₀, and NO₂) were evaluated by a satellite-based spatiotemporal model. The independent and joint associations between snoring and air pollutants on prevalence of hypertension were analyzed by logistic regression models.

RESULTS

The mean age of all participants was 56.0 ± 12.2 years. The frequencies and prevalence of participants with hypertension were 3666 (32.39%) in men and 5576(32.57%) in women, respectively. The odds ratio (OR) and 95% confidence interval (CI) of participants with snoring frequency of <3 times/week, ≥3 times/week was 1.10(1.02-1.20), and 1.15(1.08-1.23) for hypertension, compared to those without snoring. Participants with a snoring (≥3 times/week) and higher exposure concentrations of PM₁, PM_2.5, PM₁₀, and NO₂ had 2.58-fold(95% CI: 2.30-2.90), 3.03-fold(95% CI: 2.69-3.41), 2.89-fold(95% CI: 2.57-3.25) and 2.75-fold(95% CI: 2.44-3.10) for hypertension, compared to those without snoring and low concentrations of air pollutants. Additionally, participants with high PM₁ and ≥3 times/week snoring (OR: 1.32, 95% CI: 1.18-1.48) was at a higher likelihood for prevalent hypertension, compared to those without snoring and with high PM₁.

CONCLUSIONS

Snoring and high ambient air pollutants might be important predictors of hypertension, and higher concentration of PM₁ might aggravate the association between snoring and hypertension.

Geographic variations in the blood pressure responses to short-term fine particulate matter exposure in China

Results from recent studies on associations between blood pressure (BP) and short-term exposure to fine particulate matter (PM_2.5) have been inconsistent. Most studies have been evaluations of small geographic areas, with no national study in China. This study aimed to examine the acute BP responses to ambient PM_2.5 among the general population of Chinese adults. During 2012-2015, systolic and diastolic BP levels were obtained from a large national representative sample, the China Hypertension Survey database (n = 479,842). Daily PM_2.5 average exposures with a spatial resolution of 0.1° were estimated using a data assimilation that combines satellite measurements, air model simulations, and monitoring values. Overall, a 10-μg/m³ increase in daily PM_2.5 was associated with a 0.035 (95% confidence interval: 0.020, 0.049) mmHg change in systolic BP and 0.001 (-0.008, 0.011) mmHg in diastolic BP after adjustments. Stratified by geographic regions, the systolic and diastolic BP levels varied from -0.050 (-0.109, 0.010) to 0.242 (0.176, 0.307) mmHg, and from -0.026 (-0.053, 0.001) to 0.051 (0.020, 0.082) mmHg, respectively. Statistically significant positive BP-PM_2.5 associations were only found in South and North China for systolic levels and in Southwest China for diastolic levels. We further explored the regional study population characteristics and exposure-response curves, and found that the geographic variations in BP-PM_2.5 associations were probably due to different population compositions or different PM_2.5 exposure levels. Our study provided national-level evidence on the associations between ambient PM_2.5 exposure and elevated BP levels. The magnitude of the estimated associations varied substantially by geographic location in China. CLINICAL TRIAL REGISTRATION: The Clinical trial registration name was Survey on prevalence of hypertension in China; the registration number was ChiCTR-ECS-14004641. http://www.chictr.org.cn/showproj.aspx?proj=4932.

Exposure to air pollution and risk of hospitalization for cardiovascular diseases amongst Vietnamese adults: Case-crossover study

BACKGROUND

Associations between hospital admissions and ambient air pollutants in the Vietnamese population have been reported in previous studies. However, most studies were conducted in Hanoi or Hochiminh city. We used hospital records of seven hospitals in Northern Vietnam to investigate short-term associations between ambient air pollutants and hospital admissions due to cardiovascular conditions.

METHODS

We used 135'101 hospital records of residents (age ≥15) living in three provinces (Hanoi, Quang Ninh, and Phu Tho) and daily ambient air pollutant concentrations to estimate percentage changes and 95% confidence intervals for hospital admissions due to seven cardiovascular conditions per interquartile range (IQR) increases in daily ambient air pollutants. We used a time-stratified case-crossover analysis adjusting for meteorological factors, indicators of holidays and influenza epidemics. We also investigated modification of effects by age groups (<65 and ≥65), seasons (cold and hot) and hospital levels (national and province level).

RESULTS

Particulate matter concentrations were positively associated with daily hospital admissions due to most cardiovascular conditions. For example, an increment in the two-day average (lag1-2) level of PM_2.5 by one IQR (34.4 µg/m³) was associated with a 6.3% (95%CI: 3.0%-9.8%) increase in the daily count of admissions for ischemic heart disease in Hanoi and with 23.2% (95%CI: 11.1%-36.5%) for cardiac failure in Quang Ninh. Moreover, hospitalisations for stroke in Hanoi and cardiac failure in Phu Tho showed strong positive associations with SO₂. The findings also show that estimates varied by age groups, seasons and hospital levels.

CONCLUSION

Ambient air pollutants were associated with daily cardiovascular admissions in Northern Vietnam. The findings underline the important role of ambient air pollutants as a trigger of cardiovascular conditions.

Influence of mental stress and environmental toxins on circadian clocks: Implications for redox regulation of the heart and cardioprotection

Risk factors in the environment such as air pollution and mental stress contribute to the development of chronic non-communicable disease. Air pollution was identified as the leading health risk factor in the physical environment, followed by water pollution, soil pollution/heavy metals/chemicals and occupational exposures, however neglecting the non-chemical environmental health risk factors (e.g. mental stress and noise). Epidemiological data suggest that environmental risk factors are associated with higher risk for cardiovascular, metabolic and mental diseases, including hypertension, heart failure, myocardial infarction, diabetes, arrhythmia, stroke, depression and anxiety disorders. We provide an overview on the impact of the external exposome comprising risk factors/exposures on cardiovascular health with a focus on dysregulation of stress hormones, mitochondrial function, redox balance and inflammation with special emphasis on the circadian clock. Finally, we assess the impact of circadian clock dysregulation on cardiovascular health and the potential of environment-specific preventive strategies or "chrono" therapy for cardioprotection. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.23/issuetoc.

Is breathing our polluted air a risk factor for stroke?

The conference "Climate change, air pollution and health" was held at the Pontifical Academy of Sciences. The data presented highlighted that air pollution is a major, under-recognized and modifiable risk factor for stroke and heart disease. Air pollution causes 7.6% of all deaths making it the fifth cause of death globally, and this figure is expected to increase by 50% by 2050. Particulate matter causes endothelial dysfunction and induces thrombosis by altering reactive oxygen species, nitric oxide, insulin resistance, and lipid levels. Thirty-three articles published since 2002 were reviewed to assess the relation between air pollution and stroke with age, geographical location, particulate and gaseous matter type, duration of exposure, previous stroke, and comorbidities. It remains to be defined if air pollution has pathophysiological effects that preferentially predispose individuals to ischemic or hemorrhagic stroke. There is ample evidence showing an association between acute and chronic exposure to PM_2.5 or gaseous pollutants with stroke. This potentially avoidable scenario and its dramatic consequences are heavily under-recognized by health professionals and the wider public. Preventive measures in people at high vascular risk are warranted. Procrastination in implementing efforts to stop the current worldwide course of worsening air pollution is the seed of a potential global health catastrophe.

Metabolomics analysis of a mouse model for chronic exposure to ambient PM2.5

Chronic ambient fine particulate matter (PM_2.5) exposure correlates with various adverse health outcomes. Its impact on the circulating metabolome-a comprehensive functional readout of the interaction between an organism's genome and environment-has not however been fully understood. This study thus performed metabolomics analyses using a chronic PM_2.5 exposure mouse model. C57Bl/6J mice (female) were subjected to inhalational concentrated ambient PM_2.5 (CAP) or filtered air (FA) exposure for 10 months. Their sera were then analyzed by liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS). These analyses identified 2570 metabolites in total, and 148 of them were significantly different between FA- and CAP-exposed mice. The orthogonal partial least-squares discriminant analysis (OPLS-DA) and heatmap analyses displayed evident clustering of FA- and CAP-exposed samples. Pathway analyses identified 6 perturbed metabolic pathways related to amino acid metabolism. In contrast, biological characterization revealed that 71 differential metabolites were related to lipid metabolism. Furthermore, our results showed that CAP exposure increased stress hormone metabolites, 18-oxocortisol and 5a-tetrahydrocortisol, and altered the levels of circadian rhythm biomarkers including melatonin, retinal and 5-methoxytryptophol.

Air pollution and kidney disease: review of current evidence

Along with amazing technological advances, the industrial revolution of the mid-19th century introduced new sources of pollution. By the mid-20th century, the effects of these changes were beginning to be felt around the world. Among these changes, health problems due to environmental air pollution are increasingly recognized. At the beginning, respiratory and cardiovascular diseases were emphasized. However, accumulated data indicate that every organ system in the body may be involved, and the kidney is no exception. Although research on air pollution and kidney damage is recent, there is now scientific evidence that air pollution harms the kidney. In this holistic review, we have summarized the epidemiology, disease states and mechanisms of air pollution and kidney damage.

Circadian toxicity of environmental pollution. Inhalation of polluted air to give a precedent

Exposures to environmental stressors that derive from pollution (e.g. air, light) or lifestyle choices (e.g. diet, activity, 24-hour-×-7-day) are associated with adverse human health outcomes. For instance, there is evidence that air pollution exposure and changes in sleep/wake pattern increase the risk for vascular and cardiometabolic disorders. Interestingly, air pollution exposure affects pulmonary and cardiovascular functions that follow circadian rhythmicity and increases the risk for pulmonary and cardiovascular events that occur in diurnal patterns suggesting a link between air pollution induced cardiovascular and pulmonary injury and changes in circadian rhythm. Indeed, recent research identified circadian rhythm as an air pollution target and circadian rhythm as factor that increases air pollution sensitivity. Using air pollution exposure as precedent, this review highlights research on how environmental pollution affect circadian rhythm and how circadian rhythm affects the toxicity of environmental stressors.

In Utero Exposure to Fine Particulate Matter Causes Hypertension Due to Impaired Renal Dopamine D1 Receptor in Offspring

BACKGROUND/AIMS

Adverse environment in utero can modulate adult phenotypes including blood pressure. Fine particulate matter (PM2.5) exposure in utero causes hypertension in the offspring, but the exact mechanisms are not clear. Renal dopamine D1 receptor (D1R), regulated by G protein-coupled receptor kinase type 4 (GRK4), plays an important role in the regulation of renal sodium transport and blood pressure. In this present study, we determined if renal D1R dysfunction is involved in PM2.5-induced hypertension in the offspring.

METHODS

Pregnant Sprague-Dawley rats were given an oropharyngeal drip of PM2.5 (1.0 mg/kg) at gestation day 8, 10, and 12. The blood pressure, 24-hour sodium excretion, and urine volume were measured in the offspring. The expression levels of GRK4 and D1R were determined by immunoblotting. The phosphorylation of D1R was investigated using immunoprecipitation. Plasma malondialdehyde and superoxide dismutase levels were also measured in the offspring.

RESULTS

As compared with saline-treated dams, offspring of PM2.5-treated dams had increased blood pressure, impaired sodium excretion, and reduced D1R-mediated natriuresis and diuresis, accompanied by decreased renal D1R expression and GRK4 expression. The impaired renal D1R function and increased GRK4 expression could be caused by increased reactive oxidative stress (ROS) induced by PM2.5 exposure. Administration of tempol, a redox-cycling nitroxide, for 4 weeks in the offspring of PM2.5-treated dam normalized the decreased renal D1R expression and increased renal D1R phosphorylation and GRK4 expression. Furthermore, tempol normalized the increased renal expression of c-Myc, a transcription factor that regulates GRK4 expression.

CONCLUSIONS

In utero exposure to PM2.5 increases ROS and GRK4 expression, impairs D1R-mediated sodium excretion, and increases blood pressure in the offspring. These studies suggest that normalization of D1R function may be a target for the prevention and treatment of the hypertension in offspring of mothers exposed to PM2.5 during pregnancy.

Traffic-related air pollution associated with chronic kidney disease among elderly residents in Taipei City

The associations of air pollution with chronic kidney disease (CKD) have not yet been fully studied. We enrolled 8,497 Taipei City residents older than 65 years and calculated the estimated glomerular filtration rate (eGFR) using the Taiwanese Chronic Kidney Disease Epidemiology Collaboration equation. Proteinuria was assessed via dipstick on voided urine. CKD prevalence and risk of progression were defined according to the KDIGO 2012 guidelines. Land-use regression models were used to estimate the participants' one-year exposures to PM of different sizes and traffic-related exhaust, PM_2.5 absorbance, nitrogen dioxide (NO₂), and NO_x. Generalized linear regressions and logistic regressions were used to examine the associations of one-year air pollution exposures with eGFR, proteinuria, CKD prevalence and risk of progression. The results showed that the interquartile range (IQR) increments of PM_2.5 absorbance (0.4 × 10^-5/m) and NO₂ (7.0 μg/m³) were associated with a 1.07% [95% confidence interval (CI): 0.54-1.57] and 0.84% (95% CI: 0.37-1.32) lower eGFR, respectively; such relationships were magnified in subjects who had an eGFR >60 ml/min/1.73 m² or who were non-diabetic. Similar associations were also observed for PM₁₀ and PM_2.5-10. Two-pollutant models showed that PM₁₀ and PM_2.5 absorbance were associated with a lower eGFR. The odd ratios (ORs) of CKD prevalence and risk of progression also increased with exposures to PM_2.5 absorbance and NO_2. In summary, one-year exposures to traffic-related air pollution were associated with lower eGFR, higher CKD prevalence, and increased risk of CKD progression among the elderly population. Air pollution-related impaired renal function was stronger in non-CKD and non-diabetic subjects.

Association between Exposure to Ambient Air Particulates and Metabolic Syndrome Components in a Saudi Arabian Population

Recent epidemiological evidence suggests that exposure to particulates may be a factor in the etiology of metabolic syndrome (MetS). In this novel study, we investigated the relationship between particulate levels and prevalence of MetS component abnormalities (hypertension, hyperglycemia, obesity) in a recruited cohort (N = 2025) in Jeddah, Saudi Arabia. We observed significant associations between a 10 μg/m³ increase in PM_2.5 and increased risks for MetS (Risk Ratio (RR): 1.12; 95% Confidence Interval (CI): 1.06-1.19), hyperglycemia (RR: 1.08; 95% CI: 1.03-1.14), and hypertension (RR: 1.09; 95% CI: 1.04-1.14). PM_2.5 from soil/road dust was found to be associated with hyperglycemia (RR: 1.12; 95% CI: 1.06-1.19) and hypertension (RR: 1.11; 95% CI: 1.05-1.18), while PM_2.5 from traffic was associated with hyperglycemia (RR: 1.33; 95% CI: 1.05-1.71). We did not observe any health associations with source-specific mass exposures. Our findings suggest that exposure to specific elemental components of PM_2.5, especially Ni, may contribute to the development of cardiometabolic disorders.

Associations of short-term exposure to ambient air pollutants with emergency ambulance calls for the exacerbation of essential arterial hypertension

We investigated the association between daily emergency ambulance calls (EAC) for elevated blood pressure that occurred during the time intervals of 8:00-13:59, 14:00-21:59, and 22:00-7:59, and exposure to CO, PM₁₀, and ozone. We used Poisson regression to explore the association between the risk of EAC and short-term variation of pollutants, adjusting for seasonality and weather variables. Before noon, the risk was associated with an interquartile range (IQR) (7.9 μg/m³) increase in PM₁₀ at lag 2-4 days below the median (RR = 1.08, p = 0.031) and with an IQR (0.146 mg/m³) increase in CO at lag 6-7 below the median (RR = 1.05, p = 0.028). During 14:00-21:59, the risk was associated with an IQR (18.8 μg/m³) increase in PM₁₀ on the previous day below the median (RR = 1.04, p = 0.031). At night, EAC were negatively affected by lower O₃ (lag 0-2) below the median (per IQR decrease RR = 1.10, p = 0.018) and a higher PM₁₀ at lag 0-1 above the median for the elderly (RR = 1.07, p = 0.030).

Effect of short-term exposure to ambient air particulate matter on incidence of delirium in a surgical population

Delirium remains an independent risk factor for morbidity and mortality among older surgical adults. Recent research has shed light on the relationship between pollution and dementia, yet little is known about the health impacts of particulate matter (PM) on delirium. Therefore, we aim to further explore association of PM and delirium among surgical population. We conducted a time-stratified case-crossover study. Electronic hospitalization summary reports derived from 26 major cities in China between 1 January 2014 and 31 December 2015 were used. Conditional logistic regression were applied to explore the association between perioperative PM exposure and delirium. A total of 559 surgical patients with delirium were identified. Both PM2.5 and SO₂ on the day of surgery had a negative impact, with an interquartile range (IQR) increase in PM2.5 (47.5 μg/m³) and SO₂ (22.2 μg/m³) significantly associated with an 8.79% (95% confidence interval [CI], 0.01–18.47%, P < 0.05) and 16.83% (95% CI, 0.10–36.35%, P < 0.05) increase in incidence of delirium, respectively. PM on other days during the perioperative period showed no significant impact. The present study showed that short-term exposure to ambient air PM on the day of surgery increased the incidence of delirium in a surgical population during hospitalization.

Seasonality of sodium and potassium consumption in Switzerland. Data from three cross-sectional, population-based studies

BACKGROUND AND AIM

Blood pressure displays a seasonal pattern. Whether this pattern is related to high sodium and/or low potassium intakes has not been investigated. We assessed if sodium and potassium consumption present a seasonal pattern. We also simulated the impact of seasonality of sodium consumption on systolic blood pressure levels.

METHODS AND RESULTS

Data from three Swiss population-based studies (n = 2845). Sodium and potassium consumption were assessed by urinary excretion using 24 h urine collection. Seasonality was assessed using the cosinor model and was adjusted for study, gender, age, body mass index, antihypertensive drug treatment, urinary creatinine and atmospheric relative humidity. The effect of sodium variation on blood pressure levels was estimated using data from a recent meta-analysis. Both sodium and potassium excretions showed a seasonal pattern. For sodium, the nadir occurred between August and October, and the peak between February and April, with a multivariate-adjusted seasonal variation (difference between peak and nadir) of 9.2 mmol. For potassium, the nadir occurred in October and the peak in April, with a multivariate-adjusted seasonal variation of 4.0 mmol. Excluding participants on antihypertensive drug treatment or stratifying the analysis by gender cancelled the seasonality of sodium consumption. The maximum impact of the seasonal variation in sodium consumption on systolic blood pressure ranged from 0.4 to 1.1 mm Hg, depending on the model considered.

CONCLUSION

Sodium and potassium consumptions present specific seasonal variations. These variations do not explain the seasonal variations in blood pressure levels.

Circadian blood pressure abnormalities in patients with primary nephrotic syndrome

BACKGROUND

Only a few studies have evaluated the abnormalities of ambulatory blood pressure (ABP) in patients with nephrotic syndrome (NS).

METHODS

The 24-h ABPs were measured in primary NS patients with acute onset of disease and analyzed in relation to the clinical variables.

RESULTS

Our subjects comprised 21 patients: 17 with minimal change disease and 4 with focal segmental glomerulosclerosis. Of these patients, 8 (38%) had daytime hypertension, 13 (62%) had nighttime hypertension, and 13 (62%) were non-dippers (nighttime-to-daytime ratio of ABP: NDR > 0.9). The serum sodium level was correlated with the average 24-h ABP and NDR, after adjustment for other clinical variables, such as the increase in body weight, serum albumin level, and urinary protein excretion. The data from repeated ABP measurements, before and after the achievement of remission, showed a marked decrease in the average 24-h ABP after remission. Furthermore, change in the serum sodium level was significantly correlated with the change in NDR.

CONCLUSION

These results suggest that alteration in renal handling of sodium and water, which might be reflected in serum sodium level, is involved in the abnormality of circadian blood pressure in primary NS patients.

Cardiovascular Benefits of Wearing Particulate-Filtering Respirators: A Randomized Crossover Trial

BACKGROUND

Practical approaches to protect individuals from ambient particulate matter (PM) are urgently needed in developing countries. Evidence on the health benefits of wearing particulate-filtering respirators is limited.

OBJECTIVES

We evaluated the short-term cardiovascular health effects of wearing respirators in China.

METHODS

A randomized crossover trial was performed in 24 healthy young adults in Shanghai, China in 2014. The subjects were randomized into two groups and wore particulate-filtering respirators for 48 hr alternating with a 3-week washout interval. Heart rate variability (HRV) and ambulatory blood pressure (BP) were continuously monitored during the 2nd 24 hr in each intervention. Circulating biomarkers were measured at the end of each intervention. Linear mixed-effect models were applied to evaluate the effects of wearing respirators on health outcomes.

RESULTS

During the intervention periods, the mean daily average concentration of PM with an aerodynamic diameter < 2.5 μm (PM2.5) was 74.2 μg/m3. Compared with the absence of respirators, wearing respirators was associated with a decrease of 2.7 mmHg [95% confidence interval (CI): 0.1, 5.2 mmHg] in systolic BP and increases of HRV parameters, including 12.5% (95% CI: 3.8%, 21.2%) in high frequency (HF) power, 10.9% (95% CI: 1.8%, 20.0%) in the root mean square of the successive differences, and 22.1% (95% CI: 3.6%, 40.7%) in the percentage of normal RR intervals with duration > 50 msec different from the previous normal RR interval (pNN50). The presence of respirators was also associated with a decrease of 7.8% (95% CI: 3.5%, 12.1%) in the ratio of low frequency (LF)/HF power.

CONCLUSIONS

Short-term wearing of particulate-filtering respirators may produce cardiovascular benefits by improving autonomic nervous function and reducing BP. Citation: Shi J, Lin Z, Chen R, Wang C, Yang C, Cai J, Lin J, Xu X, Ross JA, Zhao Z, Kan H. 2017. Cardiovascular benefits of wearing particulate-filtering respirators: a randomized crossover trial. Environ Health Perspect 125:175-180; http://dx.doi.org/10.1289/EHP73.

Associations of Short-Term and Long-Term Exposure to Ambient Air Pollutants With Hypertension

Hypertension is a major disease of burden worldwide. Previous studies have indicated that air pollution might be a risk factor for hypertension, but the results were controversial. To fill this gap, we performed a meta-analysis of epidemiological studies to investigate the associations of short-term and long-term exposure to ambient air pollutants with hypertension. We searched all of the studies published before September 1, 2015, on the associations of ozone (O 3 ), carbon monoxide (CO), nitrogen oxide (NO 2 and NO X ), sulfur dioxide (SO 2 ), and particulate matter (PM 10 and PM 2.5 ) with hypertension in the English electronic databases. A pooled odds ratio (OR) for hypertension in association with each 10 μg/m 3 increase in air pollutant was calculated by a random-effects model (for studies with significant heterogeneity) or a fixed-effect model (for studies without significant heterogeneity). A total of 17 studies examining the effects of short-term (n=6) and long-term exposure (n=11) to air pollutants were identified. Short-term exposure to SO 2 (OR=1.046, 95% confidence interval [CI]: 1.012–1.081), PM 2.5 (OR=1.069, 95% CI: 1.003–1.141), and PM 10 (OR=1.024, 95% CI: 1.016–1.032) were significantly associated with hypertension. Long-term exposure (a 10 μg/m 3 increase) to NO 2 (OR=1.034, 95% CI: 1.005–1.063) and PM 10 (OR=1.054, 95% CI: 1.036–1.072) had significant associations with hypertension. Exposure to other ambient air pollutants (short-term exposure to NO 2 , O 3 , and CO and long-term exposure to NO x , PM 2.5 , and SO 2 ) also had positive relationships with hypertension, but lacked statistical significance. Our results suggest that short-term or long-term exposure to some air pollutants may increase the risk of hypertension.