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BACKGROUND: Emissions control programs targeting certain air pollution sources may alter PM(2.5) composition, as well as the risk of adverse health outcomes associated with PM(2.5). OBJECTIVES: We examined temporal changes in the risk of emergency department (ED) visits for cardiovascular diseases (CVDs) and asthma associated with short-term increases in ambient PM(2.5) concentrations in Los Angeles, California. METHODS: Poisson log-linear models with unconstrained distributed exposure lags were used to estimate the risk of CVD and asthma ED visits associated with short-term increases in daily PM(2.5) concentrations, controlling for temporal and meteorological confounders. The models were run separately for three predefined time periods, which were selected based on the implementation of multiple emissions control programs (EARLY: 2005-2008; MIDDLE: 2009-2012; LATE: 2013-2016). Two-pollutant models with individual PM(2.5) components and the remaining PM(2.5) mass were also considered to assess the influence of changes in PM(2.5) composition on changes in the risk of CVD and asthma ED visits associated with PM(2.5) over time. RESULTS: The relative risk of CVD ED visits associated with a 10 μg/m(3) increase in 4-day PM(2.5) concentration (lag 0-3) was higher in the LATE period (rate ratio = 1.020, 95% confidence interval = [1.010, 1.030]) compared to the EARLY period (1.003, [0.996, 1.010]). In contrast, for asthma, relative risk estimates were largest in the EARLY period (1.018, [1.006, 1.029]), but smaller in the following periods. Similar temporal differences in relative risk estimates for CVD and asthma were observed among different age and season groups. No single component was identified as an obvious contributor to the changing risk estimates over time, and some components exhibited different temporal patterns in risk estimates from PM(2.5) total mass, such as a decreased risk of CVD ED visits associated with sulfate over time. CONCLUSIONS: Temporal changes in the risk of CVD and asthma ED visits associated with short-term increases in ambient PM(2.5) concentrations were observed. These changes could be related to changes in PM(2.5) composition (e.g., an increasing fraction of organic carbon and a decreasing fraction of sulfate in PM(2.5)). Other factors such as improvements in healthcare and differential exposure misclassification might also contribute to the changes.

Prior work found increased rates for emergency department (ED) visits for asthma and hospitalizations for chronic obstructive pulmonary disease per unit mass of PM(2.5) across New York State (NYS) during 2014 to 2016 after major reductions in ambient PM2.5 concentrations had occurred following implementation of various policy actions and major economic disruptions. The associations of source-specific PM(2.5) concentrations with these respiratory diseases were assessed with a time-stratified case-control design and logistic regression models to identify the changes in the PM(2.5) that have led to the apparently increased toxicity per unit mass. The rates of ED visits and hospitalizations for asthma and COPD associated with increases in source-specific PM2.5 concentrations in the prior 1, 4, and 7 days were estimated for 6 urban sites in New York State. Overall, there were similar numbers of significantly increased (n=9) and decreased rates (n=8) of respiratory events (asthma and COPD hospitalizations and ED visits) associated with increased source-specific PM(2.5) concentrations in the previous 1, 4, and 7 days. Associations of source-specific PM(2.5) concentrations with excess rates of hospitalizations for COPD for spark- and compression ignition vehicles increased in the 2014–2016 period, but the values were not statistically significant. Other source types showed inconsistent patterns of excess rates. For asthma ED visits, only biomass burning and road dust showed consistent positive associations with road dust having significant values for most lag times. Secondary nitrate also showed significant positive associations with asthma ED visits in the AFTER period compared to no associations in the prior periods. These results suggest that the relationships of asthma and COPD exacerbation with source-specific PM(2.5) are not well defined and further work will be needed to determine the causes of the apparent increases in the per unit mass toxicity of PM(2.5) in New York State in the 2014–16 period.

Background Emissions control programs targeting certain air pollution sources may alter PM2.5 composition, as well as the risk of adverse health outcomes associated with PM2.5. Objectives We examined temporal changes in the risk of emergency department (ED) visits for cardiovascular diseases (CVDs) and asthma associated with short-term increases in ambient PM2.5 concentrations in Los Angeles, California. Methods Poisson log-linear models with unconstrained distributed exposure lags were used to estimate the risk of CVD and asthma ED visits associated with short-term increases in daily PM2.5 concentrations, controlling for temporal and meteorological confounders. The models were run separately for three predefined time periods, which were selected based on the implementation of multiple emissions control programs (EARLY: 2005-2008; MIDDLE: 2009-2012; LATE: 2013-2016). Two-pollutant models with individual PM2.5 components and the remaining PM2.5 mass were also considered to assess the influence of changes in PM2.5 composition on changes in the risk of CVD and asthma ED visits associated with PM2.5 over time. Results The relative risk of CVD ED visits associated with a 10 μg/m3 increase in 4-day PM2.5 concentration (lag 0-3) was higher in the LATE period (rate ratio = 1.020, 95% confidence interval = [1.010, 1.030]) compared to the EARLY period (1.003, [0.996, 1.010]). In contrast, for asthma, relative risk estimates were largest in the EARLY period (1.018, [1.006, 1.029]), but smaller in the following periods. Similar temporal differences in relative risk estimates for CVD and asthma were observed among different age and season groups. No single component was identified as an obvious contributor to the changing risk estimates over time, and some components exhibited different temporal patterns in risk estimates from PM2.5 total mass, such as a decreased risk of CVD ED visits associated with sulfate over time. Conclusions Temporal changes in the risk of CVD and asthma ED visits associated with short-term increases in ambient PM2.5 concentrations were observed. These changes could be related to changes in PM2.5 composition (e.g., an increasing fraction of organic carbon and a decreasing fraction of sulfate in PM2.5). Other factors such as improvements in healthcare and differential exposure misclassification might also contribute to the changes.

Background: Previous studies suggest that pathways reducing oxidative stress may have a protective effect against adverse cardiac responses associated with ambient PM. However, few studies have directly assessed total antioxidant capacity (TAC) as a potential effect modifier of cardiac responses to increased ambient PM. Objectives: We examined if TAC modifies the association between ambient PM and markers of heart rate variability (HRV), repolarization, systemic inflammation, and systolic blood pressure (SBP) in post-infarction patients. Methods: We recruited 76 patients with a recent coronary event (myocardial infarction or unstable angina) who participated in a cardiac rehabilitation program from June 2006 to November 2009 in Rochester, New York. Ambient fine particle (PM2.5,≤2.5 μm in aerodynamic diameter), accumulation mode particle (AMP, 100-500 nm) and ultrafine particle (UFP, 10-100 nm) concentrations were measured continuously by fixed-site monitors. Markers of HRV and repolarization were measured by continuous Holter electrocardiogram (ECG) recordings before and during exercise sessions of the rehabilitation program. Blood pressure was measured and venous blood samples were collected before exercise to measure TAC and inflammation markers. We applied linear mixed models to assess changes in markers of HRV, repolarization, systemic inflammation, and SBP associated with increased PM concentrations in the low, medium and high TAC tertile groups, after adjusting for covariates including temperature, calendar time since the beginning of the study, visit number, month of year, and hour of day. Results: Based on subject-visits with available TAC, we observed increases in SBP, C-reactive protein, and fibrinogen, and decreases in rMSSD (square root of the mean of the sum of the squared differences between adjacent normal to normal intervals) and SDNN (standard deviation of normal to normal beat intervals) associated with increased PM2.5, AMP and UFP in the previous 6-120 h (e.g. change in SBP associated with each interquartile range (IQR) increase in PM2.5 lagged 0-5 h was 1.27 mmHg [95%CI: 0.09, 2.46 mmHg]). However, we did not observe a consistent pattern of effect measure modification by TAC for any combination of pollutant and outcome (e.g. changes in SBP associated with each IQR increase in PM2.5 lagged 0-5 h for the low, medium and high TAC tertile groups were 1.93 mmHg [95%CI: 0.23, 3.63 mmHg], -0.31 mmHg [95%CI: -2.62, 2.01 mmHg], and 1.29 mmHg [95%CI: -0.64, 3.21 mmHg], respectively. P for interaction=0.28). Conclusions: In a post-infarction population, total antioxidant capacity does not appear to modify the association between biomarkers of heart rate variability, repolarization, systemic inflammation, and systolic blood pressure and ambient PM concentrations in the previous 6-120 h.

Land-use regression (LUR) models provide location and time specific estimates of exposure to air pollution and thereby improve the sensitivity of health effects models. However, they require pollutant concentrations at multiple locations along with land-use variables. Often, monitoring is performed over short durations using mobile monitoring with research-grade instruments. Low-cost PM monitors provide an alternative approach that increases the spatial and temporal resolution of the air quality data. LUR models were developed to predict hourly PM concentrations across a metropolitan area using PM concentrations measured simultaneously at multiple locations with low-cost monitors. Monitors were placed at 23 sites during the 2015/16 heating season. Monitors were externally calibrated using co-located measurements including a reference instrument (GRIMM particle spectrometer). LUR models for each hour of the day and weekdays/weekend days were developed using the deletion/substitution/addition algorithm. Coefficients of determination for hourly PM predictions ranged from 0.66 and 0.76 (average 0.7). The hourly-resolved LUR model results will be used in epidemiological studies to examine if and how quickly, increases in ambient PM concentrations trigger adverse health events by reducing the exposure misclassification that arises from using less time resolved exposure estimates.

Objectives Increased air pollutant concentrations have been linked to several asthma-related outcomes in children, including respiratory symptoms, medication use, and hospital visits. However, few studies have examined effects of ultrafine particles in a pediatric population. Our primary objective was to examine the effects of ambient concentrations of ultrafine particles on asthma exacerbation among urban children and determine whether consistent treatment with inhaled corticosteroids could attenuate these effects. We also explored the relationship between asthma exacerbation and ambient concentrations of accumulation mode particles, fine particles (≤2.5 micrograms [μm]; PM 2.5 ), carbon monoxide, sulfur dioxide, and ozone. We hypothesized that increased 1–7 day concentrations of ultrafine particles and other pollutants would be associated with increases in the relative odds of an asthma exacerbation, but that this increase in risk would be attenuated among children receiving school-based corticosteroid therapy. Methods We conducted a pilot study using data from 3 to 10 year-old children participating in the School-Based Asthma Therapy trial. Using a time-stratified case-crossover design and conditional logistic regression, we estimated the relative odds of a pediatric asthma visit treated with prednisone ( n =96 visits among 74 children) associated with increased pollutant concentrations in the previous 7 days. We re-ran these analyses separately for children receiving medications through the school-based intervention and children in a usual care control group. Results Interquartile range increases in ultrafine particles and carbon monoxide concentrations in the previous 7 days were associated with increases in the relative odds of a pediatric asthma visit, with the largest increases observed for 4-day mean ultrafine particles (interquartile range=2088 p/cm 3 ; OR=1.27; 95% CI=0.90–1.79) and 7-day mean carbon monoxide (interquartile range=0.17 ppm; OR=1.63; 95% CI=1.03–2.59). Relative odds estimates were larger among children receiving school-based inhaled corticosteroid treatment. We observed no such associations with accumulation mode particles, black carbon, fine particles (≤2.5 μm), or sulfur dioxide. Ozone concentrations were inversely associated with the relative odds of a pediatric asthma visit. Conclusions These findings suggest a response to markers of traffic pollution among urban asthmatic children. Effects were strongest among children receiving preventive medications through school, suggesting that this group of children was particularly sensitive to environmental triggers. Medication adherence alone may be insufficient to protect the most vulnerable from environmental asthma triggers. However, further research is necessary to confirm this finding.

Background Increased particulate air pollution has been associated with both an increased risk of myocardial infarction (MI) and adverse changes in cardiac biomarkers. Up to 30% of ambient wintertime fine particles (PM 2.5 ) in Rochester, NY are from wood burning. Our study examined associations between ambient levels of a marker of wood smoke (Delta-C) and other particulate air pollutants and biomarkers of inflammation, coagulation and thrombosis. Methods We measured blood concentrations of C-reactive protein (CRP), D -dimer, fibrinogen, P-selectin, platelet factor 4 (PF-4), von Willebrand factor (vWF), and myeloperoxidase (MPO) of 135 patients undergoing cardiac catheterization during the winters of 2011–2013. We coupled these data with hourly ambient concentrations of Delta-C, black carbon (BC; marker of traffic pollution), and ultrafine (10–100 nm; UFP), accumulation mode (100–500 nm; AMP), and fine particles ( 2.5 ). Using linear regression models, we estimated the change in each biomarker associated with increased pollutant concentrations at intervals between 1 and 96 h preceding blood collection. Results Each 0.13 µg/m 3 increase in Delta-C concentration in the prior 12 h was associated with a 0.91% increase in fibrinogen levels (95% CI=0.23%, 1.59%), but unexpectedly in the prior 48 h, each 0.17 µg/m 3 increase in Delta-C concentration was associated with a 2.75% decrease in MPO levels (95% CI=−5.13%,−0.37%). We did not see associations between Delta-C concentrations and any other biomarkers. Interquartile range (IQR) increases in PM 2.5, BC, UFP, and AMP concentrations were generally associated with increased CRP and fibrinogen, but not PF4, D -dimer, vWF, or P-selectin. Conclusions In a population of cardiac patients, we noted adverse changes in fibrinogen associated with increased concentrations of a marker of wood smoke. Increases in PM 2.5 , BC, AMP, and UFP concentrations in the previous 96 h were also associated with adverse changes in markers of systemic inflammation and coagulation, but not with markers of endothelial cell dysfunction or platelet activation.

Background Previously, we reported a 18% increased odds of ST-elevation myocardial infarction (STEMI) associated with each 7.1 µg/m3 increase in PM2.5 concentration in the hour prior to MI onset. We found no association with non-ST elevation myocardial infarction (NSTEMI). We examined if this association was modified by PM2.5 source direction. Methods We used the NOAA HYbrid Single-Particle Lagrangian Trajectory (HYSPLIT) model to calculate each hourly air mass location for the 24 hours before each case or control time period in our previous PM2.5/STEMI case-crossover analysis. Using these data on patients with STEMI (n=338), hourly PM2.5 concentrations, and case-crossover methods, we evaluated whether our PM2.5/STEMI association was modified by whether the air mass passed through each of the 8 cardinal wind direction sectors in the previous 24 h. Results When the air mass passed through the West-Southwest direction (WSW) any time in the past 24 h, the odds of STEMI associated with each 7.1 µg/m3 increase in PM2.5 concentration in the previous hour (OR=1.27; 95% CI=1.08, 1.22) was statistically significantly (p=0.01) greater than the relative odds of STEMI associated with increased PM2.5 concentration when the wind arrived from any other direction (OR=0.99; 95% CI=0.80, 1.22). We found no other effect modification by any other source direction. Further, relative odds estimates were largest when the time spent in the WSW was 8–16 h, compared to ≤7 h or 17–24 h, suggesting that particles arising from sources in this direction were more potent in triggering STEMIs. Conclusions Since relative odds estimates were higher when the air mass passed through the WSW octant in the past 24 h, there may be specific components of the ambient aerosol that are more potent in triggering STEMIs. This direction is associated with substantial emissions from coal-fired power plants and other industrial sources of the Ohio River Valley, many of which are undergoing modifications to reduce their emissions.