Fine Particulate Matter Constituents Research Articles

Fine particulate matter constituents and blood pressure in patients with chronic obstructive pulmonary disease: A panel study in Shanghai, China

ObjectiveThe evidence is limited about the potentially different health effects of various chemical constituents of fine particulate matter (PM2.5). We thus assessed the acute effects of various chemical constituents of PM2.5 on blood pressure (BP). MethodsWe performed a longitudinal panel study with six repeated visits in 28 urban residents with chronic obstructive pulmonary disease in Shanghai, China from May to July, 2014. Twelve (43%) of them took antihypertensive medications. We measured resting BP by using a mercury sphygmomanometer and monitored real-time concentrations of PM2.5 constituents at a nearby site. Based on the linear mixed-effects model, we evaluated the effects of 10 major constituents in PM2.5 on BP, using a single-constituent model and a constituent-residual model after accounting for the multicollinearity. ResultsWe obtained a total of 168 pairs of effective BP measurements during the study period. There are moderate or high correlations among various PM2.5 constituents. An interquartile range increase of PM2.5 (19.1μg/m3) was associated with increments of 1.90mmHg [95% confidence interval (CI): 0.66, 3.13] in systolic BP, 0.68mmHg (95%CI: −0.02, 1.37) in diastolic BP and 1.23mmHg (95%CI: 0.19, 2.29) in pulse pressure. Some constituents of PM2.5, including organic carbon, elemental carbon, nitrate and ammonium, were robustly associated with elevated BP after controlling for total PM2.5 mass and accounting for multi-collinearity. Two constituents (magnesium and calcium) were associated with decreased BP. ConclusionsOrganic carbon, elemental carbon, nitrate and ammonium may be mainly responsible for elevated BP from a short-term exposure to PM2.5.

Association between PM2.5 and PM2.5 Constituents and Preterm Delivery in California, 2000-2006.

Particulate matter (PM) has been documented to contribute to preterm delivery. However, few studies have investigated the relationships between individual constituents of fine PM (PM2.5 ) and preterm delivery, and factors that may modify their associations. In this study, we examined the associations between several prenatal exposure metrics to PM2.5 and 23 constituents of PM2.5 and preterm delivery in California from 2000 to 2006. In a retrospective cohort study including 231 637 births, we conducted logistic regression analyses adjusting for maternal, infant, temporal, geographic, and neighbourhood characteristics. We observed increased risk for preterm delivery with full-gestational exposure for several PM2.5 constituents. Per interquartile range increase, ammonium (21.2%, 95% confidence interval (CI) 17.1, 25.4), nitrate (18.1%, 95% CI 14.9, 21.4) and bromine (16.7%, 95% CI 13.2, 20.3) had some of the largest increased risks. Alternatively, some PM2.5 constituents were inversely associated with preterm delivery, including chlorine (-8.2%, 95% CI -10.3, -6.0), sodium (-13.2%, 95% CI -15.2, -11.3), sodium ion (-11.9%, 95% CI -14.1, -9.6) and vanadium (-19.2%, 95% CI -25.3, -12.6). Greater associations between PM2.5 constituents and preterm delivery were observed for Blacks and Asians, older mothers, and those with some college education compared to their reference groups, as well as for births with gestational ages from 32 to 34 weeks. PM2.5 constituents ammonium, nitrate and bromine, often linked to traffic and biomass combustion, were most associated with increased risk of preterm delivery in California. Certain demographic subgroups may be particularly impacted.

The Acute Effects of Fine Particulate Matter Constituents on Blood Inflammation and Coagulation.

Limited evidence is available on the effects of various fine particulate matter (PM2.5) constituents on blood inflammation and coagulation. We examined the associations between 10 constituents and 10 circulating biomarkers in a panel of 28 urban residents with four repeated measurements in Shanghai, China. Based on the linear mixed-effect models, we fitted the single-constituent models, the constituent-PM2.5 joint models, and the constituent-residual models to evaluate the associations between PM2.5 constituents and eight inflammatory biomarkers (fibrinogen, C-reactive protein, monocyte chemoattractant protein-1, tumor necrosis factor-α, interleukin-1b, intercellular adhesion molecule-1, P-selectin, vascular cell adhesion molecule-1) and two coagulation biomarkers (plasminogen activator inhibitor-1 and soluble CD40 ligand). We found robust associations of organic carbon (OC), elemental carbon (EC), nitrate (NO3-), and ammonium (NH4+) with at least 1 of 8 inflammatory markers. On average, an interquartile range increase in the four constituents corresponded to increments of 50%, 37%, 25%, and 26% in inflammatory biomarkers, respectively. Only sulfate (SO42-) or NH4+ was robustly associated with coagulation markers (corresponding increments: 23% and 20%). Our results provided evidence that some constituents in PM2.5 (OC, EC, NO3-, SO42-, and NH4+) might play crucial roles in inducing systematic inflammation and coagulation, but their roles varied by the selected biomarkers.

Ambient temperature and air quality in relation to small for gestational age and term low birthweight

BackgroundExposures to extreme ambient temperature and air pollution are linked to adverse birth outcomes, but the associations with small for gestational age (SGA) and term low birthweight (tLBW) are unclear. We aimed to investigate exposures to site-specific temperature extremes and selected criteria air pollutants in relation to SGA and tLBW. MethodsWe linked medical records of 220,572 singleton births (2002–2008) from 12 US sites to local temperature estimated by the Weather Research and Forecasting model, and air pollution estimated by modified Community Multiscale Air Quality models. Exposures to hot (>95th percentile) and cold (<5th percentile) were defined using site-specific distributions of daily temperature over three-month preconception, each trimester, and whole-pregnancy. Average concentrations of five criteria air pollutants and six fine particulate matter constituents were also calculated for these pregnancy windows. Poisson regression with generalized estimating equations calculated the relative risks (RR) and 95% confidence intervals for SGA (weight <10th percentile conditional on gestational age and sex) and tLBW (≥37 weeks and <2500g) associated with an interquartile range increment of air pollutants, and cold or hot compared to mild (5–95th percentile) temperature. Models were adjusted for maternal demographics, lifestyle, and clinical factors, season, and site. ResultsCompared to mild temperature, cold exposure during trimester 2 [RR: 1.21 (1.05–1.38)], trimester 3 [RR: 1.18 (1.03–1.36)], and whole-pregnancy [RR: 2.57 (2.27–2.91)]; and hot exposure during trimester 3 [RR: 1.31 (1.15–1.50)] and whole-pregnancy [RR: 2.49 (2.20–2.83)] increased tLBW risk. No consistent association was observed between temperature and SGA. Air pollutant analyses were generally null but preconception elemental carbon was associated with a 4% increase in SGA while dust particles increased tLBW by 10%. Particulate matter ≤10µm in the second trimester and whole pregnancy also appeared related to tLBW. ConclusionsOur findings suggest prenatal exposures to extreme ambient temperature relative to usual environment may increase tLBW risk. Given concerns related to climate change, these findings merit further investigation.

Fine Particulate Constituents and Lung Dysfunction: A Time-Series Panel Study.

The evidence is quite limited regarding the constituents of fine particulate matter (PM2.5) responsible for lung dysfunction. We designed a time-series panel study in 28 patients to examine the effects of 10 major constituents of PM2.5 on lung function with repeated daily measurements from December 2012 to May 2013 in Shanghai, China. We applied a linear mixed-effect model combined with a distributed lag model to estimate the cumulative effects of PM2.5 constituents on morning/evening forced expiratory volume in 1-s (FEV1) and peak expiratory flow (PEF) over a week. The cumulative decreases in morning FEV1, evening FEV1, morning PEF and evening PEF associated with an interquartile range (35.8 μg/m3) increase in PM2.5 concentrations were 33.49 [95% confidence interval(CI):2.45,54.53] mL, 16.80 (95%CI:3.75,29.86) mL, 4.48 (95%CI:2.30,6.66) L/min, and 1.31 (95%CI:-0.85,3.47) L/min, respectively. These results were not substantially changed after adjusting for gases in two-pollutant models. The associations of elemental carbon (EC) and nitrates with morning/evening FEV1, and the associations of EC and sulfates with morning PEF were robust after controlling for PM2.5. This study demonstrated that short-term exposure to PM2.5 was associated with reduced pulmonary function. Some constituents (EC, sulfate and nitrate) may be responsible for the detrimental effects.

Association Between PM2.5 and PM2.5 Constituents and Preterm Birth in California, 2000-2006

Particulate matter (PM) has been associated with an increased risk of preterm birth (PTB) in many studies. However, few have investigated the relationship between individual constituents of fine PM...

Rapid determination of trace polycyclic aromatic hydrocarbons in particulate matter using accelerated solvent extraction followed by ultra high performance liquid chromatography with fluorescence detection.

A method has been developed for the trace analysis of polycyclic aromatic hydrocarbons, which are known as persistent organic pollutants and ubiquitous constituents of fine particulate matter that causes growing airborne pollution. The method, which was especially for samples of airborne particulate matter less than 2.5 μm in diameter, utilized accelerated solvent extraction and ultra high performance liquid chromatography with fluorescence detector. Four principal parameters of accelerated solvent extraction were optimized to obtain maximum extraction efficiency. Using the established synergetic programs of gradient elution and fluorescence wavelength switching, a rapid separation was achieved in 6.56 min with good linearity for 15 polycyclic aromatic hydrocarbons (coefficient of determination above 0.999). The limits of detection ranged from 0.833 to 10.0 pg/m(3) . The precision of the method expressed as inter-day relative standard deviation ranged from 0.2 to 1%, which was calculated from nine repetitive measurements of 8.00 μg/L analytes. Average spiked recoveries ranged from 71.6 to 97.7%, with the exception of naphthalene. The rapid, sensitive, and accurate method can meet the pressing needs of health risk assessment and increasingly heavy daily tasks of air quality monitoring.

Fine Particulate Matter Constituents, Nitric Oxide Synthase DNA Methylation and Exhaled Nitric Oxide

It remains unknown how fine particulate matter (PM2.5) constituents affect differently the fractional concentration of exhaled nitric oxide (FeNO, a biomarker of airway inflammation) and the DNA methylation of its encoding gene (NOS2A). We aimed to investigate the short-term effects of PM2.5 constituents on NOS2A methylation and FeNO. We designed a longitudinal study among chronic obstructive pulmonary disease (COPD) patients with six repeated health measurements in Shanghai, China. We applied linear mixed-effect models to evaluate the associations. We observed that the inverse association between PM2.5 and methylation at position 1 was limited within 24 h, and the positive association between PM2.5 and FeNO was the strongest at lag 1 day. Organic carbon, element carbon, NO3(-) and NH4(+) were robustly and significantly associated with decreased methylation and elevated FeNO. An interquartile range increase in total PM2.5 and the four constituents was associated with decreases of 1.19, 1.63, 1.62, 1.17, and 1.14 in percent methylation of NOS2A, respectively, and increases of 13.30%,16.93%, 8.97%, 18.26%, and 11.42% in FeNO, respectively. Our results indicated that organic carbon, element carbon, NO3(-) and NH4(+) might be mainly responsible for the effects of PM2.5 on the decreased NOS2A DNA methylation and elevated FeNO in COPD patients.

Effect Of Fine Particulate Matter And Its Constituents On Mortality During Asian Dust Storm Events In Seoul, Korea

Although the difference in fine particulate matter (PM2.5) constituents during Asian dust storms (ADS) and non-ADS days has been reported in previous studies, the difference in health effects of PM...

Associations between long-term exposure to chemical constituents of fine particulate matter (PM2.5) and mortality in Medicare enrollees in the eastern United States.

Background:Several epidemiological studies have reported that long-term exposure to fine particulate matter (PM2.5) is associated with higher mortality. Evidence regarding contributions of PM2.5 constituents is inconclusive.Objectives:We assembled a data set of 12.5 million Medicare enrollees (≥ 65 years of age) to determine which PM2.5 constituents are a) associated with mortality controlling for previous-year PM2.5 total mass (main effect); and b) elevated in locations exhibiting stronger associations between previous-year PM2.5 and mortality (effect modification).Methods:For 518 PM2.5 monitoring locations (eastern United States, 2000–2006), we calculated monthly mortality rates, monthly long-term (previous 1-year average) PM2.5, and 7-year averages (2000–2006) of major PM2.5 constituents [elemental carbon (EC), organic carbon matter (OCM), sulfate (SO42–), silicon (Si), nitrate (NO3–), and sodium (Na)] and community-level variables. We applied a Bayesian hierarchical model to estimate location-specific mortality rates associated with previous-year PM2.5 (model level 1) and identify constituents that contributed to the spatial variability of mortality, and constituents that modified associations between previous-year PM2.5 and mortality (model level 2), controlling for community-level confounders.Results:One–standard deviation (SD) increases in 7-year average EC, Si, and NO3– concentrations were associated with 1.3% [95% posterior interval (PI): 0.3, 2.2], 1.4% (95% PI: 0.6, 2.4), and 1.2% (95% PI: 0.4, 2.1) increases in monthly mortality, controlling for previous-year PM2.5. Associations between previous-year PM2.5 and mortality were stronger in combination with 1-SD increases in SO42– and Na.Conclusions:Long-term exposures to PM2.5 and several constituents were associated with mortality in the elderly population of the eastern United States. Moreover, some constituents increased the association between long-term exposure to PM2.5 and mortality. These results provide new evidence that chemical composition can partly explain the differential toxicity of PM2.5.Citation:Chung Y, Dominici F, Wang Y, Coull BA, Bell ML. 2015. Associations between long-term exposure to chemical constituents of fine particulate matter (PM2.5) and mortality in Medicare enrollees in the eastern United States. Environ Health Perspect 123:467–474; http://dx.doi.org/10.1289/ehp.1307549

Respiratory hospitalizations in association with fine PM and its components in New York State

Despite observed geographic and temporal variation in particulate matter (PM)-related health morbidities, only a small number of epidemiologic studies have evaluated the relation between PM2.5 chemical constituents and respiratory disease. Most assessments are limited by inadequate spatial and temporal resolution of ambient PM measurements and/or by their approaches to examine the role of specific PM components on health outcomes. In a case-crossover analysis using daily average ambient PM2.5 total mass and species estimates derived from the Community Multiscale Air Quality (CMAQ) model and available observations, we examined the association between the chemical components of PM (including elemental and organic carbon, sulfate, nitrate, ammonium, and other remaining) and respiratory hospitalizations in New York State. We evaluated relationships between levels (low, medium, high) of PM constituent mass fractions, and assessed modification of the PM2.5–hospitalization association via models stratified by mass fractions of both primary and secondary PM components. In our results, average daily PM2.5 concentrations in New York State were generally lower than the 24-hr average National Ambient Air Quality Standard (NAAQS). Year-round analyses showed statistically significant positive associations between respiratory hospitalizations and PM2.5 total mass, sulfate, nitrate, and ammonium concentrations at multiple exposure lags (0.5–2.0% per interquartile range [IQR] increase). Primarily in the summer months, the greatest associations with respiratory hospitalizations were observed per IQR increase in the secondary species sulfate and ammonium concentrations at lags of 1–4 days (1.0–2.0%). Although there were subtle differences in associations observed between mass fraction tertiles, there was no strong evidence to support modification of the PM2.5-respiratory disease association by a particular constituent. We conclude that ambient concentrations of PM2.5 and secondary aerosols including sulfate, ammonium, and nitrate were positively associated with respiratory hospitalizations, although patterns varied by season. Exposure to specific fine PM constituents is a plausible risk factor for respiratory hospitalization in New York State.Implications: The association between ambient concentrations of PM2.5 components has been evaluated in only a small number of epidemiologic studies with refined spatial and temporal scale data. In New York State, fine PM and several of its constituents, including sulfate, ammonium, and nitrate, were positively associated with respiratory hospitalizations. Results suggest that PM species relationships and their influence on respiratory endpoints are complex and season dependent. Additional work is needed to better understand the relative toxicity of PM species, and to further explore the role of co-pollutant relationships and exposure prediction error on observed PM–respiratory disease associations.

Association between particulate matter and its chemical constituents of urban air pollution and daily mortality or morbidity in Beijing City.

Recent time series studies have indicated that daily mortality and morbidity are associated with particulate matters. However, about the relative effects and its seasonal patterns of fine particulate matter constituents is particularly limited in developing Asian countries. In this study, we examined the role of particulate matters and its key chemical components of fine particles on both mortality and morbidity in Beijing. We applied several overdispersed Poisson generalized nonlinear models, adjusting for time, day of week, holiday, temperature, and relative humidity, to investigate the association between risk of mortality or morbidity and particulate matters and its constituents in Beijing, China, for January 2005 through December 2009. Particles and several constituents were associated with multiple mortality or morbidity categories, especially on respiratory health. For a 3-day lag, the nonaccident mortality increased by 1.52, 0.19, 1.03, 0.56, 0.42, and 0.32% for particulate matter (PM)2.5, PM10, K(+), SO4(2-), Ca(2+), and NO3(-) based on interquartile ranges of 36.00, 64.00, 0.41, 8.75, 1.43, and 2.24 μg/m(3), respectively. The estimates of short-term effects for PM2.5 and its components in the cold season were 1 ~ 6 times higher than that in the full year on these health outcomes. Most of components had stronger adverse effects on human health in the heavy PM2.5 mass concentrations, especially for K(+), NO3(-), and SO4(2-). This analysis added to the growing body of evidence linking PM2.5 with mortality or morbidity and indicated that excess risks may vary among specific PM2.5 components. Combustion-related products, traffic sources, vegetative burning, and crustal component and resuspended road dust may play a key role in the associations between air pollution and public health in Beijing.

Meta-Analytic Approaches for Multistressor Dose-Response Function Development: Strengths, Limitations, and Case Studies.

For many policy analyses, including but not limited to cumulative risk assessments, it is important to characterize the individual and joint health effects of multiple stressors. With an increasing focus on psychosocial and other nonchemical stressors, this often includes epidemiological meta-analysis. Meta-analysis has limitations if epidemiological studies do not include all of the stressors of interest or do not provide multivariable outputs in a format necessary for risk assessment. Given these limitations, novel analytical methods are often needed to synthesize the published literature or to build upon available evidence. In this article, we discuss three recent case studies that highlight the strengths and limitations of meta-analytic approaches and other research synthesis techniques for human health risk assessment applications. First, a literature-based meta-analysis within a risk assessment context informed the design of a new epidemiological investigation of the differential toxicity of fine particulate matter constituents. Second, a literature synthesis for an effects-based cumulative risk assessment of hypertension risk factors led to a decision to develop new epidemiological associations using structural equation modeling. Third, discrete event simulation modeling was used to simulate the impact of changes in the built environment on environmental exposures and associated asthma outcomes, linking literature meta-analyses for key associations with a simulation model to synthesize all of the model components. These case studies emphasize the importance of conducting epidemiology with a risk assessment application in mind, the need for interdisciplinary collaboration, and the value of advanced analytical methods to synthesize epidemiological and other evidence for risk assessment applications.

Molecular Composition of Boreal Forest Aerosol from Hyytiälä, Finland, Using Ultrahigh Resolution Mass Spectrometry

Organic compounds are important constituents of fine particulate matter (PM) in the troposphere. In this study, we applied direct infusion nanoelectrospray (nanoESI) ultrahigh resolution mass spectrometry (UHR-MS) and liquid chromatography LC/ESI-UHR-MS for the analysis of the organic fraction of PM1 aerosol samples collected over a two week period at a boreal forest site (Hyytiälä), southern Finland. Elemental formulas (460-730 in total) were identified with nanoESI-UHR-MS in the negative ionization mode and attributed to organic compounds with a molecular weight below 400. Kendrick Mass Defect and Van Krevelen approaches were used to identify compound classes and mass distributions of the detected species. The molecular composition of the aerosols strongly varied between samples with different air mass histories. An increased number of nitrogen, sulfur, and highly oxygenated organic compounds was observed during the days associated with continental air masses. However, the samples with Atlantic air mass history were marked by a presence of homologous series of unsaturated and saturated C12-C20 fatty acids suggesting their marine origin. To our knowledge, we show for the first time that the highly detailed chemical composition obtained from UHR-MS analyses can be clearly linked to meteorological parameters and trace gases concentrations that are relevant to atmospheric oxidation processes. The additional LC/ESI-UHR-MS analysis revealed 29 species, which were mainly attributed to oxidation products of biogenic volatile compounds BVOCs (i.e., α,β-pinene, Δ3-carene, limonene, and isoprene) supporting the results from the direct infusion analysis.

Blood Pressure Changes and Chemical Constituents of Particulate Air Pollution: Results from the Healthy Volunteer Natural Relocation (HVNR) Study

Background: Elevated blood pressure (BP) has been associated with particulate matter (PM) air pollution, but associations with PM chemical constituents are still uncertain.Objectives: We investigated associations of BP with various chemical constituents of fine PM (PM2.5) during 460 repeated visits among a panel of 39 university students.Methods: Resting BP was measured using standardized methods before and after the university students relocated from a suburban campus to an urban campus with different air pollution contents in Beijing, China. Air pollution data were obtained from central monitors close to student residences. We used mixed-effects models to estimate associations of various PM2.5 constituents with systolic BP (SBP), diastolic BP (DBP), and pulse pressure.Results: An interquartile range increase of 51.2 μg/m3 in PM2.5 was associated with a 1.08-mmHg (95% CI: 0.17, 1.99) increase in SBP and a 0.96-mmHg (95% CI: 0.31, 1.61) increase in DBP on the following day. A subset of PM2.5 constituents, including carbonaceous fractions (organic carbon and elemental carbon), ions (chloride and fluoride), and metals/metalloid elements (nickel, zinc, magnesium, lead, and arsenic), were found to have robust positive associations with different BP variables, though robust negative associations of manganese, chromium, and molybdenum with SBP or DBP also were observed.Conclusions: Our results support relationships between specific PM2.5 constituents and BP. These findings have potential implications for the development of pollution abatement strategies that maximize public health benefits.

A Meta-Analysis and Multisite Time-Series Analysis of the Differential Toxicity of Major Fine Particulate Matter Constituents

Health risk assessments of particulate matter less than 2.5 μm in diameter (PM(2.5)) often assume that all constituents of PM(2.5) are equally toxic. While investigators in previous epidemiologic studies have evaluated health risks from various PM(2.5) constituents, few have conducted the analyses needed to directly inform risk assessments. In this study, the authors performed a literature review and conducted a multisite time-series analysis of hospital admissions and exposure to PM(2.5) constituents (elemental carbon, organic carbon matter, sulfate, and nitrate) in a population of 12 million US Medicare enrollees for the period 2000-2008. The literature review illustrated a general lack of multiconstituent models or insight about probabilities of differential impacts per unit of concentration change. Consistent with previous results, the multisite time-series analysis found statistically significant associations between short-term changes in elemental carbon and cardiovascular hospital admissions. Posterior probabilities from multiconstituent models provided evidence that some individual constituents were more toxic than others, and posterior parameter estimates coupled with correlations among these estimates provided necessary information for risk assessment. Ratios of constituent toxicities, commonly used in risk assessment to describe differential toxicity, were extremely uncertain for all comparisons. These analyses emphasize the subtlety of the statistical techniques and epidemiologic studies necessary to inform risk assessments of particle constituents.

Fine Particulate Matter Constituents and Cardiopulmonary Mortality in a Heavily Polluted Chinese City

Background: Although ambient fine particulate matter (PM2.5; particulate matter ≤ 2.5 µm in aerodynamic diameter) has been linked to adverse human health effects, the chemical constituents that cause harm are unknown. To our knowledge, the health effects of PM2.5 constituents have not been reported for a developing country.Objectives: We examined the short-term association between PM2.5 constituents and daily mortality in Xi’an, a heavily polluted Chinese city.Methods: We obtained daily mortality data and daily concentrations of PM2.5, organic carbon (OC), elemental carbon (EC), and 10 water-soluble ions for 1 January 2004 through 31 December 2008. We also measured concentrations of fifteen elements 1 January 2006 through 31 December 2008. We analyzed the data using over-dispersed generalized linear Poisson models.Results: During the study period, the mean daily average concentration of PM2.5 in Xi’an was 182.2 µg/m3. Major contributors to PM2.5 mass included OC, EC, sulfate, nitrate, and ammonium. After adjustment for PM2.5 mass, we found significant positive associations of total, cardiovascular, or respiratory mortality with OC, EC, ammonium, nitrate, chlorine ion, chlorine, and nickel for at least 1 lag day. Nitrate demonstrated stronger associations with total and cardiovascular mortality than PM2.5 mass. For a 1-day lag, interquartile range increases in PM2.5 mass and nitrate (114.9 and 15.4 µg/m3, respectively) were associated with 1.8% [95% confidence interval (CI): 0.8%, 2.8%] and 3.8% (95% CI: 1.7%, 5.9%) increases in total mortality.Conclusions: Our findings suggest that PM2.5 constituents from the combustion of fossil fuel may have an appreciable influence on the health effects attributable to PM2.5 in Xi’an.

Air Pollution and Health: Bridging the Gap from Sources to Health Outcomes

The U.S. Environmental Protection Agency (EPA) has established National Ambient Air Quality Standards (NAAQS) for six principal air pollutants (“criteria” pollutants): carbon monoxide (CO), lead (Pb), nitrogen dioxide (NO2), particulate matter (PM) in two size ranges [< 2.5 μm (PM2.5) and < 10 μm (PM10)], ozone (O3), and sulfur dioxide (SO2) (U.S. EPA 2010b). Although associations have been identified between these pollutants and adverse health effects, considerable uncertainty remains regarding a) methods and approaches to understanding relationships between air pollution and health effects; b) which components (gas and/or aerosol) and sources are most toxic; c) the mechanisms of actions of the pollutants and causal relationships; d) effect of confounding factors, and e) which populations are susceptible {U.S. EPA 2006a (Pb), 2006b (O3), 2008a [NOx Integrated Science Assessment (ISA)], 2008b (SOx ISA), 2009 (PM), 2010 (CO)}. This holds true especially for PM, because it is composed of many components with significant spatial and temporal variation (U.S. EPA 2009). Air pollution and health research continues to reduce these uncertainties across the source-to-health effects paradigm as described by the National Research Council (NRC) Research Priorities for Airborne Particulate Matter, volumes I–IV, (NRC 1998, 1999, 2001, 2004) and the U.S. EPA (2006a, 2006b, 2008a, 2008b, 2009b, 2010a). Linking air pollution and adverse health effects is complicated and requires expertise across a range of scientific disciplines—from atmospheric to exposure to health sciences, as well as inclusion of air quality managers and policy makers who implement and develop policy to reduce risk from air pollution. Interaction among these groups at different points in time helps to identify gaps in knowledge and suggest future research directions. One such opportunity was the international specialty conference “Air Pollution and Health: Bridging the Gap from Sources to Health Outcomes,” sponsored by the American Association for Aerosol Research (AAAR 2010). The conference, chaired by myself and Maria Costantini (Health Effects Institute), was designed to help disseminate and integrate results from scientific studies that cut across the range of air pollution– and health-related disciplines of the source-to-health effects continuum. The conference addressed the science of air pollution and health within a multipollutant framework, focusing on five key science areas—sources, atmospheric sciences, exposure, dose, and health effects—as identified by the NRC (1998). Eight key policy-relevant science questions that integrated across various parts of these science areas formed the basis of the meeting, and a ninth question addressed the policy implications of the findings (see Appendix). This was the AAAR’s third international specialty conference and extended the findings presented at the AAAR’s first specialty conference “Particulate Matter: Atmospheric Sciences, Exposure, and the Fourth Colloquium on PM and Human Health,” held in Pittsburgh, Pennsylvania, in 2003 (Davidson et al. 2005). Results from the 2010 AAAR Air Pollution and Health conference are being published in Environmental Health Perspectives (EHP); Air Quality, Atmosphere and Health; Aerosol Science and Technology; Atmospheric Environment; and Inhalation Toxicology (Solomon 2010). This issue of EHP includes conference papers on the importance of a multipollutant approach and of individual components of particulate matter to understanding linkages between sources and adverse health outcomes, including respiratory and/or cardiovascular diseases (Ito et al. 2011; Lall et al. 2011; Rohr et al. 2011; Spira-Cohen et al. 2011; Zhou et al. 2011), associated effects, such as inflammation (Alexeeff et al. 2011), and birth outcomes associated with exposures to traffic-related pollution during gestation (Malmqvist et al. 2011). Several air pollution components and sources were evaluated, including elemental carbon and secondary organic aerosol, traffic, local industrial sources, and residential oil and wood burning. Where studied, some effects varied by season and location over sufficient time (specifically, Detroit, MI; Seattle, WA; New York, NY), likely due to the influence of different source impacts. In addition, this issue includes a review of population characteristics related to susceptibility (Sacks et al. 2011), and an accountability study of the feasibility of hybrid regional–local modeling to assess health improvements in small communities (Lobdell et al. 2011).

Association of Exposure to Fine Particulate Matter Constituents and Sources With Birth Weight

PP-31-003 Background/Aims: Exposure to fine particles (particulate matter [PM2.5]) during pregnancy has been linked to lower birth weight; however, the chemical composition of PM2.5 varies widely. We investigated whether PM2.5 mass, constituents, and sources are associated with birth weight. Methods: PM2.5 filters were analyzed for over 50 elements for the period August 2000 to February 2004 for 3 counties in Connecticut and 1 in Massachusetts. Source apportionment techniques were used to estimate the daily contributions of PM2.5 associated with the sources of traffic, road dust/crustal, oil combustion, salt, and regional (sulfur). Gestational exposure to PM2.5 mass, constituents, and sources were examined in relation to birth weight and risk of low birth weight (<2500 g) for 76,788 infants. Results: Road dust and associated constituents, silicon and aluminum were associated with lower birth weight, as were the motor vehicle-related species such as elemental carbon and zinc, and the oil combustion-associated elements vanadium and nickel. An interquartile range increase in exposure was associated with low birth weight for zinc (12% increase in risk, 95% confidence interval [CI]: 3%–21%), elemental carbon (13%, 95% CI: 3%–24%), silicon (10%, 95% CI: 3%–13%), aluminum (11%, 95% CI: 3%–20%), vanadium (8%, 95% CI: 2%–15%), and nickel (11%, 95% CI: 3%–19%). Conclusion: Findings indicate that higher levels of certain chemical constituents of PM2.5 are associated with lower birth weight and increased risk of birth weight <2500 g. Evidence on the sources or constituents of particles that are most harmful is valuable to decision-makers in establishing public health policies.

Fine Particulate Matter Constituents Associated with Cardiovascular Hospitalizations and Mortality in New York City

BackgroundRecent time-series studies have indicated that both cardiovascular disease (CVD)mortality and hospitalizations are associated with particulate matter (PM). However, seasonal patterns of PM associations with these outcomes are not consistent, and PM components responsible for these associations have not been determined. We investigated this issue in New York City (NYC), where PM originates from regional and local combustion sources.ObjectiveIn this study, we examined the role of particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5) and its key chemical components on both CVD hospitalizations and on mortality in NYC.MethodsWe analyzed daily deaths and emergency hospitalizations for CVDs among persons ≥ 40 years of age for associations with PM2.5, its chemical components, nitrogen dioxide (NO2), carbon monoxide, and sulfur dioxide for the years 2000–2006 using a Poisson time-series model adjusting for temporal and seasonal trends, temperature effects, and day of the week. We estimated excess risks per interquartile-range increases at lags 0 through 3 days for warm (April through September) and cold (October through March) seasons.ResultsThe CVD mortality series exhibit strong seasonal trends, whereas the CVD hospitalization series show a strong day-of-week pattern. These outcome series were not correlated with each other but were individually associated with a number of PM2.5 chemical components from regional and local sources, each with different seasonal patterns and lags. Coal-combustion–related components (e.g., selenium) were associated with CVD mortality in summer and CVD hospitalizations in winter, whereas elemental carbon and NO2 showed associations with these outcomes in both seasons.ConclusionLocal combustion sources, including traffic and residual oil burning, may play a year-round role in the associations between air pollution and CVD outcomes, but transported aerosols may explain the seasonal variation in associations shown by PM2.5 mass.