Coarse Particulate Matter Concentrations Research Articles

Coarse particulate matter air quality in East Asia: implications for fine particulate nitrate

Abstract. Air quality network data in China and South Korea show very high year-round mass concentrations of coarse particulate matter (PM), as inferred by the difference between PM10 and PM2.5. Coarse PM concentrations in 2015 averaged 52 µg m−3 in the North China Plain (NCP) and 23 µg m−3 in the Seoul Metropolitan Area (SMA), contributing nearly half of PM10. Strong daily correlations between coarse PM and carbon monoxide imply a dominant source from anthropogenic fugitive dust. Coarse PM concentrations in the NCP and the SMA decreased by 21 % from 2015 to 2019 and further dropped abruptly in 2020 due to COVID-19 reductions in construction and vehicle traffic. Anthropogenic coarse PM is generally not included in air quality models but scavenges nitric acid to suppress the formation of fine particulate nitrate, a major contributor to PM2.5 pollution. GEOS-Chem model simulation of surface and aircraft observations from the Korea–United States Air Quality (KORUS-AQ) campaign over the SMA in May–June 2016 shows that consideration of anthropogenic coarse PM largely resolves the previous model overestimate of fine particulate nitrate. The effect is smaller in the NCP which has a larger excess of ammonia. Model sensitivity simulations for 2015–2019 show that decreasing anthropogenic coarse PM directly increases PM2.5 nitrate in summer, offsetting 80 % the effect of nitrogen oxide and ammonia emission controls, while in winter the presence of coarse PM increases the sensitivity of PM2.5 nitrate to ammonia and sulfur dioxide emissions. Decreasing coarse PM helps to explain the lack of decrease in wintertime PM2.5 nitrate observed in the NCP and the SMA over the 2015–2021 period despite decreases in nitrogen oxide and ammonia emissions. Continuing decrease of fugitive dust pollution means that more stringent nitrogen oxide and ammonia emission controls will be required to successfully decrease PM2.5 nitrate.

Does street canyon morphology shape particulate matter reduction capacity by street trees in real urban environments?

Urban street canyon morphology plays an important role in outdoor air quality and should be considered in tree planting schemes. However, the air pollutant reduction rate by street trees in different types of street canyon has rarely been analyzed for real urban environments. Therefore, this study conducted field investigation of 15 street canyons in residential areas to assess the reduction rate of particulate matter (PM) by trees in canyons with varying aspect ratio (AR) and orientation. The species of trees planted in these streets were Sophora japonica, Populus alba 'Berolinensis' L., Salix babylonica, Fraxinus chinensis, Pinus tabulaeformis, and Ulmus pumila. In the presence of trees, the mass concentration of fine PM (PM1) decreased most in narrow canyons (AR = 1.37–3.02), while the concentration of coarse PM (PM10) decreased most in wide canyons (AR = 0.45–0.69). The PM concentration increased most with tree planting in medium canyons (AR = 0.79–1.08). Additionally, street trees reduced fine PM concentration more in canyons with a 45° angle to the prevailing wind than in canyons aligned parallel to the prevailing wind. But they reduced coarse PM more in canyons aligned parallel to the prevailing wind than in canyons with a 45° angle to the prevailing wind. In comparison with tree-free cases, tree planting weakened the correlation between AR and coarse PM concentration, whereas no difference in correlation was found between AR and fine PM concentration. Overall, street canyon morphology should be considered seriously in developing tree planting guidelines for built-up environments.

Real-time measurements of mineral dust concentration in coarse particulate matter (PM10–2.5) by employing a novel optical-based technique in Los Angeles

As a primary component of coarse particulate matter (PM), ambient mineral dust has been linked to adverse health effects. Los Angeles, the largest metropolitan urban area of the United States, is impacted by both windblown and localized sources of mineral dust, often internally mixed with black carbon. The estimation of mineral dust concentrations with a high time resolution becomes critical in improving our understanding of its sources and temporal trends. Using Aethalometers combined with a high-volume virtual impactor (VI) to enrich coarse (2.5 <dp < 10 μm) particles, the light absorption and mass concentration of mineral dust were estimated in real-time during summer, fall, and winter over 2020–2021. The concentration-enriched coarse PM was collected on Teflon filters, and its chemical composition in terms of trace elements and metals was chemically quantified. The high time-resolution measurements enabled us to calculate the absorption coefficient of enriched dust particles by subtracting the light absorption of the post-VI coarse PM from that of the PM2.5 aerosol fraction to reduce the impact of stronger light absorbers in ambient PM. Mineral dust was more prevalent during the fall and winter campaigns (i.e., 19.3 and 11.4 μg/m3, respectively), lower concentrations were observed during the summer campaign (i.e., 8.50 μg/m3). The calculated absorption Ångström exponent (AAE) was 2.18, highlighting the presence of dust particles during the sampling period. The dust mass absorption coefficient was estimated to be 2.7 ± 1.6 Mm−1 at 370 nm and 0.41 ± 0.16 Mm−1 at 880 nm wavelengths, respectively. The validation of the proposed approach was investigated by comparing the evaluated mineral dust mass concentrations in this study with the reported coarse PM concentrations by the California Air Resources Board (CARB). The results reported by the optical-based approach with high temporal resolution can provide crucial information on identifying sources of mineral dust in urban areas.

Roles of meteorological factors in inter-regional variations of fine and coarse PM concentrations over the Republic of Korea

This study examined meteorological effects on airborne concentrations of particulate matter (PM) of <2.5 μm (PM2.5) and 2.5–10 μm (PM2.5–10) diameter in 16 regions of Korea, including seven metropolitan cities and nine provinces. Regional distributions of mean PM concentrations indicate that PM2.5 concentrations were higher in provinces than in metropolitan cities, while PM2.5–10 concentrations were higher in the western than eastern regions, in the season with the highest concentrations during 2015–2019. Concentrations of PM of diameter <10 μm (PM10), the sum of fine and coarse PMs, decreased over all regions during 2001–2019, particularly in Seoul, the capital of Korea. Mechanisms by which meteorological factors such as air temperature, wind, humidity, and air pressure control PM concentrations in Korea vary with region, season, and PM size. Regardless of emissions, >25% of PM2.5 variability can be explained by Random Forest regression with only atmospheric variables, compared to little accountability for PM2.5–10. The two most important variables that affect PM2.5 variability are surface air temperature and wind. Transboundary transport controlled by atmospheric factors causes fine PM from northeast and east China to affect PM2.5 variations a day after emissions in the northern-central and southern regions of Korea, respectively; and coarse PM from east China affects PM2.5–10 variations in Korea on the same day. The present results suggest that local governments of regions with high PM concentrations should strengthen regulation policies with a long-term perspective, considering future changes in atmospheric conditions that may cause increases in PM levels.

항만 배후지역의 대기오염 실태로 본 항만환경 관리정책의 새로운 방향성

The ultimate purpose of this study is to explore the possibility of air pollution and damage to the hinterland that may be caused by the development and operation of the port, and to examine it by using especially analysis and optimization methods. The Busan New Port which is the largest trading port in Korea operating across Busan and Changwon (Gyeongnam) have been undertaken. Two field experiments on the concentration of coarse particulate matter (PM10, Hereafter PM10) and the level of influence of PM10 were investigated at two sites in the industrial and residential areas behind Busan New Port (Changwon). As the results, the concentration of PM10 was different for each site. In particularly, the actual air quality was exceeded the standard set as PM10 100㎍/㎥ for the case of the industrial area within the port area. Beside that, the observated values at the residential area did not exceed the standard, but were higher than other areas’s such as Noksan-dong and Gyeonghwa-dong. In order to effectively manage air pollution in the hinterland of ports, not only environmental and technical measures, but also cooperation with the private sector and local governments should be take into account.&#x0D;

Spatio-temporal characteristics of air pollutants over Xinjiang, northwestern China.

To understand the characteristics of particulate matter (PM) and other air pollutants in Xinjiang, a region with one of the largest sand-shifting deserts in the world and significant natural dust emissions, the concentrations of six air pollutants monitored in 16 cities were analyzed for the period January 2013-June 2019. The annual mean PM2.5, PM10, SO2, NO2, CO, and O3 concentrations ranged from 51.44 to 59.54μgm-3, 128.43-155.28μgm-3, 10.99-17.99μgm-3, 26.27-31.71μgm-3, 1.04-1.32mgm-3, and 55.27-65.26μgm-3, respectively. The highest PM concentrations were recorded in cities surrounding the Taklimakan Desert during the spring season and caused by higher amounts of wind-blown dust from the desert. Coarse PM (PM10-2.5) was predominant, particularly during the spring and summer seasons. The highest PM2.5/PM10 ratio was recorded in most cities during the winter months, indicating the influence of anthropogenic emissions in winters. The annual mean PM2.5 (PM10) concentrations in the study area exceeded the annual mean guidelines recommended by the World Health Organization (WHO) by a factor of ca. ∼5-6 (∼7-8). Very high ambient PM concentrations were recorded during March 19-22, 2019, that gradually influenced the air quality across four different cities, with daily mean PM2.5 (PM10) concentrations ∼8-54 (∼26-115) times higher than the WHO guidelines for daily mean concentrations, and the daily mean coarse PM concentration reaching 4.4mgm-3. Such high PM2.5 and PM10 concentrations pose a significant risk to public health. These findings call for the formulation of various policies and action plans, including controlling the land degradation and desertification and reducing the concentrations of PM and other air pollutants in the region.

Association between African Dust Transport and Acute Exacerbations of COPD in Miami.

Background: Air pollution is increasingly recognized as a risk factor for acute exacerbation of chronic obstructive pulmonary disease (COPD). Changing climate and weather patterns can modify the levels and types of air pollutants. For example, dust outbreaks increase particulate air pollution. Objective: This paper examines the effect of Saharan dust storms on the concentration of coarse particulate matter in Miami, and its association with the risk of acute exacerbation of COPD (AECOPD). Methods: In this prospective cohort study, 296 COPD patients (with 313 events) were followed between 2013 and 2016. We used Light Detection and Ranging (LIDAR) and satellite-based Aerosol Optical Depth (AOD) to identify dust events and quantify particulate matter (PM) exposure, respectively. Exacerbation events were modeled with respect to location- and time-lagged dust and PM exposures, using multivariate logistic regressions. Measurements and main results: Dust duration and intensity increased yearly during the study period. During dust events, AOD increased by 51% and particulate matter ≤2.5 µm in aerodynamic diameter (PM2.5) increased by 25%. Adjusting for confounders, ambient temperature and local PM2.5 exposure, one-day lagged dust exposure was associated with 4.9 times higher odds of two or more (2+ hereto after) AECOPD events (odds ratio = 4.9; 95% CI = 1.8–13.4; p < 0.001). Ambient temperature exposure also showed a significant association with 2+ and 3+ AECOPD events. The risk of AECOPD lasted up to 15 days after dust exposure, declining from 10× higher on day 0 to 20% higher on day 15. Conclusions: Saharan dust outbreaks observed in Miami elevate the concentration of PM and increase the risk of AECOPD in COPD patients with recurring exacerbations.

Health exposure of users of indoor sports centers related to the physico-chemical properties of particulate matter

The aim of this study was the identification of the factors that determine the concentrations of particulate matter (PM) in the indoor air of a selected sports facility, as well as the assessment of the health exposure of the sports facility users (pupils aged 8–18 years, trainers and athletes aged 21–40 years) to PM and its components. The mass concentration of size-resolved (PM1, PM1-2.5, PM2.5-4, PM4-10, PM10-100) total suspended particles (TSP) was measured using DustTrak DRX devices. Measurements were conducted for 8 h a day, simultaneously inside and outside a typical sports hall in Warsaw, for 20 days each in the heating (16/10/–20/11/2017) and non-heating (18/05/–21/06/2017) seasons. At the same time, samples of PM4 and TSP were taken (GilAir 3 aspirators) to determine ambient concentrations of PM-bound metals and polycyclic aromatic hydrocarbons (PAH). The main factor affecting TSP concentration in the sports facility was dust resuspension; it was especially visible in variations of coarse PM concentrations. The concentrations of fine PM as well as PM-bound metals and PAHs inside the hall were determined mainly by outdoor sources – combustion of fossil fuels and non-traffic emissions. The incremental lifetime cancer risk (ILCR) related to the exposure of the sports hall users to PM-bound metals and PAHs was in the range of 6.9E-05–1.1E-04; it was higher than that calculated for PM-bound metals and PAHs in atmospheric air (5.4E-05–9.8E-05). The highest ILCR concerns pupils, which inside the sports facility is above the acceptable risk level value of 1E-04.

An Investigation of the Precipitation Net Effect on the Particulate Matter Concentration in a Narrow Valley: Role of Lower-Troposphere Stability

AbstractPrecipitation modulates the pollutant concentration in the atmosphere directly and indirectly through different mechanisms. Wet deposition, including in-cloud scavenging and below-cloud scavenging, is one of the main drivers of particulate matter removal from the atmosphere. Our focus is to assess the net effect of precipitation on the pollutant concentration using observations, a nonparametric conditional analysis, and the signed overlapping coefficient complement index. The study considers not only the direct near-surface aerosol below-cloud scavenging, but also the indirect effect associated with the induced lower-troposphere stability limiting the vertical dispersion, leading to a pollutant concentration increase. We consider the precipitation effects on fine and coarse particulate matter concentration. Probability density functions of the pollutant concentration during precipitation events and under dry conditions are analyzed for every hour of the day. The net effect of precipitation on the fine and coarse particulate matter concentration is strongly dependent on the atmospheric stability. During the nighttime and before midmorning, the atmosphere is stable; a precipitation event during this time induces below-cloud scavenging, reducing the concentration of particulate matter in the atmosphere. During the afternoon, unstable atmospheric conditions are predominant, and aerosols disperse vertically; a precipitation event during this period stabilizes the atmosphere, generating early stabilization that, together with the continued anthropogenic emissions during the day, leads to near-surface pollutant accumulation, offsetting the washout effect of the precipitation.

Association between air pollution and risk of vascular dementia: A multipollutant analysis in Taiwan

Evidence regarding the association of specific air pollutants with vascular dementia (VaD) risk is limited. In this nested case–control study, we enrolled 831 adults aged >65 years with VaD (International Classification of Diseases, Ninth Revision, Clinical Modification code 290.4x) newly diagnosed during 2005–2013; 3324 controls were age-, sex-, and VaD diagnosis year–matched with the study patients. Both patients with VaD and controls were selected from among a cohort of one million beneficiaries of Taiwan’s National Health Insurance program, all of whom were registered in 2005. Exposure to the mean daily air pollutant concentration, derived from 76 fixed air quality monitoring stations, in 3, 5, and 7 years before VaD diagnosis was assessed using the spatial analysis method (i.e., ordinary kriging) on ArcGIS. A logistic regression model was used to calculate covariate-adjusted odds ratios (ORs) of VaD in relation to specific air pollutants. After potential confounders and other air pollutants were controlled for, high concentrations of coarse particulate matter (10 µm or less in diameter) and carbon monoxide (CO) were sporadically associated with higher OR of VaD. The most prominent association was observed for nitrogen dioxide (NO2) exposure within 5 and 7 years before diagnosis. Compared with the <25th percentile of NO2 exposure, the 25th–50th, 50th–75th, and >75th percentiles of NO2 exposure significantly increased ORs (95% confidence intervals): 1.62 (1.28–2.23), 1.61 (1.11–2.33), and 2.22 (1.35–3.65) within 5 years before diagnosis, respectively, and 1.59 (1.20–2.11), 1.65 (1.15–2.37), and 2.05 (1.28–3.28) within 7 years before diagnosis, respectively. We found that higher NO2 exposure in the past was significantly associated with an elevated risk of VaD. Although less consistent, higher exposure to CO was also associated with a higher risk of VaD. Most NO2 in cities originates from motor vehicle exhaust; other sources of NO2 are petrol and metal refining, electricity generation from coal-fired power stations, other manufacturing industries, and food processing. Future studies should investigate associations of VaD with specific sources of NO2.

Cerebral ischemic attack, epilepsy and hospital admitted patients with types of headaches attributed to PM10 mass concentration in Abadan, Iran

Abstract Air pollution related damage to the Central Nervous System (CNS) has been widely neglected in studies of air pollution and adverse health outcomes. The aim of this study was to evaluate hospital admissions in Abadan, Iran for several neurological diseases including cerebral ischemic attack, epilepsy, and various types of headache on days with polluted air compared with clean days. Abadan is a city in Khuzestan Province that is located in southwestern Iran and experiences many sand and dust storms. The sampling station was located on the roof of the Department of Environment (DoE) in Abadan. Sampling was conducted over four years (from March 2012 to July 2016). Hospital admissions of patients with cerebral ischemic attack, epilepsy, and headache types from March 2012 to July 2016 were obtained from the Hospital Information System (HIS). This study showed that hospital admissions for patients with cerebral ischemic attack, epilepsy, and patients with types of headaches on dusty days increased significantly compared to hospital admissions on clean days. Also hospital admissions of these patients significantly increased with increased concentrations of coarse particulate matter (PM10). Ambient PM10 concentrations in Abadan were relatively high. Significant increases in hospital admissions in this study were related to high PM10 concentrations. Elderly and women were susceptible subpopulations showing more sensitivity to dust compared with the rest of the population. Staying indoors and using facial respirators under these emergency conditions could be effective in protecting these sensitive subjects against dust.

Chemical characterization of size-segregated PM from different public transport modes and implications of source specific contribution to public exposure.

To investigate the chemical properties of particulate matter (PM) in different public transport microenvironments in Hong Kong, the coarse (2.5-10μm) and fine (<2.5μm) PM samples were collected in three different types of transport modes including Mass Transit Railway (MTR)-Aboveground (AG), MTR Underground (UG), and Bus routes from October 2013 to April 2014. Average PM2.5 concentrations through UG, AG, and Bus routes were 47.9, 86.8, and 43.8μg m-3, respectively, whereas the coarse PM concentrations were 4-5 folds less. The PM2.5 total metal concentrations of AG route were 2.3 and 3.7 times of UG and BUS routes, respectively, compared to those in the other two routes. The most abundant metals at three stations in PM2.5 and coarse PM were quite similar and mainly generated by frictional processes of wheels, rails, and brakes of the system as well as by the mechanical wearing of these parts. The most abundant PAH in three routes in PM2.5 was ATRQN, followed by 2-MNA, and the sum of them contributed to 35 and 42% of total PAHs in coarse PM and PM2.5, respectively. Crude oils, lubricant oil, diesel emissions would be the major sources of PAHs from MTR aboveground stations. The relative abundance of the n-alkanes among different samples was similar to the PAHs and the carbon preference index (CPI) values of the whole n-alkanes range were consistently from 0.99 to 1.04 among all samples indicating the significant contribution from the vehicle exhaust and fossil fuel burning. The concentrations of hopanes and steranes were higher in PM2.5 than in coarse PM due to diesel and coal burning. These results may provide a unique opportunity to investigate source specific contribution of the PM pollutants to the commuter exposure in public transport.

Residential Air Pollution, Road Traffic, Greenness and Maternal Hypertension: Results from GINIplus and LISAplus.

Background: The public health burden of hypertension is high, but its relationship with long-term residential air pollution, road traffic, and greenness remains unclear.Objective: To investigate associations between residential air pollution, traffic, greenness, and hypertension among mothers. Methods: Information on doctor-diagnosed maternal hypertension was collected at the 15-year follow-up of two large population-based multicenter German birth cohorts—GINIplus and LISAplus (n=3063). Residential air pollution was modelled by land use regression models within the ESCAPE and universal kriging within the APMoSPHERE projects. Road traffic was defined as traffic load on major roads within a 100-m buffer around residences. Vegetation level (ie, greenness) was defined as the mean Normalized Difference Vegetation Index in a 500-m buffer around residences and was assessed from Landsat 5 TM satellite images. All the exposure variables were averaged over three residential addresses during the last 10 years and categorized into tertiles or dichotomized. The individual associations between each of the exposure variables and hypertension were assessed using logistic regression analysis. Results: No significant and consistent associations across different levels of adjustment were observed between the exposures of interest and hypertension. The only significant estimate was found with coarse particulate matter concentrations (OR 1.66, 95% CI 1.01 to 2.74; 3rd vs 1st tertile) among mothers residing in the Wesel area. No significant associations were observed with traffic load or greenness. Conclusion: This study does not provide evidence on detrimental effects of air pollution and road traffic or beneficial effects of greenness on hypertension among German adults.

Acute effects of ambient temperature and particulate air pollution on fractional exhaled nitric oxide: A panel study among diabetic patients in Shanghai, China.

BackgroundEpidemiological studies have shown the associations of ambient temperature and particulate matter (PM) air pollution with respiratory morbidity and mortality. However, the underlying mechanisms have not been well characterized. The aim of this study is to investigate the associations of temperature and fine and coarse PM with fractional exhaled nitric oxide (FeNO), a well-established biomarker of respiratory inflammation.MethodsWe conducted a longitudinal panel study involving six repeated FeNO tests among 33 type 2 diabetes mellitus patients from April to June 2013 in Shanghai, China. Hourly temperature and PM concentrations were obtained from a nearby fixed-site monitoring station. We then explored the associations between temperature, PM, and FeNO using linear mixed-effect models incorporated with distributed lag nonlinear models for the lagged and nonlinear associations. The interactions between temperature and PM were evaluated using stratification analyses.ResultsWe found that both low and high temperature, as well as increased fine and coarse PM, were significantly associated with FeNO. The cumulative relative risk of FeNO was 1.75% (95% confidence interval [CI], 1.04–2.94) comparing 15 °C to the referent temperature (24 °C) over lags 0–9 days. A 10 μg/m3 increase in fine and coarse PM concentrations were associated with 1.18% (95% CI, 0.18–2.20) and 1.85% (95% CI, 0.62–3.09) FeNO in lag 0–1 days, respectively. PM had stronger effects on cool days than on warm days.ConclusionsThis study suggested low ambient temperature, fine PM, and coarse PM might elevate the levels of respiratory inflammation. Our findings may help understand the epidemiological evidence linking temperature, particulate air pollution, and respiratory health.

Measurement and Impact Assessment of PM&amp;lt;sub&amp;gt;10&amp;lt;/sub&amp;gt; in Ambient Air of BSCIC Bagerhat

The study measured the concentration of coarse particulate matter (PM10) in the ambient air of Bangladesh Small and Cottage Industries Corporation (BSCIC) Bagerhat in order to evaluate its impact on workers’ health. 14 known-volume air samples were obtained through Envirotech APM 541 PM10 Particulate Sampler. The short-term (6 hours) samples were taken from 9 industrial units in the winter season of October, 2015 to January, 2016. Simple gravimetric analysis showed large variations in concentrations in distinct industrial units. The minimum concentration was found 33.61 μ/m3 in the outdoor premises of a coconut oil mill and the maximum was found 471.38 μ/m3 in the house of a rice mill. The pollutant sources were detected as cabinless husking machines and soot from boilers and fryers. A questionnaire survey was conducted to evaluate the mostly occurring symptoms of Chronic Obstructive Pulmonary Diseases (COPD) and bronchoconstriction among workers. The highest prevalence of symptoms of bronchoconstriction (OR = 7.1; 95% CI = 2.3 - 21.9) was found among workers in rice mills and eye disturbances (OR = 2.7; 95% CI = 0.9 - 8.6) had the highest prevalence in coconut mills. Monitoring of air quality, providing personal respiratory prevention and improvement in machineries were required in the study area for a healthy environment.

Evaluation of PM surface concentrations simulated by Version 1 of NASA's MERRA Aerosol Reanalysis over Europe

This article evaluates the concentrations of particulate matter (PM) and some of its chemical speciation such as sulfate, organic carbon, black carbon and sea salt particles simulated at the surface by Version 1 of the Aerosol Reanalysis of NASA's Modern-Era Retrospective Analysis for Research and Application (MERRAero) over Europe. Measurement data from the European Monitoring and Evaluation Programme database were used. The concentrations of coarse PM (PM10), fine PM (PM2.5), sulfate and black carbon particles are overall well simulated, despite a slight and consistent overestimation of PM10 concentration, and a slight and consistent underestimation of PM2.5 and sulfate concentrations throughout most of the year. The concentration of organic carbon was largely underestimated, especially in winter, caused by two specific monitoring stations in Italy, resulting in an overall poor performance for this particular species. After removing these two stations from the sample, the evaluation of OC substantially improved but an underestimation in winter remained. Carbon emissions originating from anthropogenic sources, such as residential wood burning in winter, unresolved by MERRAero provide a plausible explanation for this discrepancy. The evaluation of PM2.5, sulfate and organic carbon concentrations improved during the summer. The concentration of fine sea salt particles was consistently and largely overestimated, but contributes relatively little to total PM2.5 concentration.

Feasibility of using low-cost portable particle monitors for measurement of fine and coarse particulate matter in urban ambient air

ABSTRACTExposure to ambient particulate matter (PM) is known as a significant risk factor for mortality and morbidity due to cardiorespiratory causes. Owing to increased interest in assessing personal and community exposures to PM, we evaluated the feasibility of employing a low-cost portable direct-reading instrument for measurement of ambient air PM exposure. A Dylos DC 1700 PM sensor was collocated with a Grimm 11-R in an urban residential area of Houston Texas. The 1-min averages of particle number concentrations for sizes between 0.5 and 2.5 µm (small size) and sizes larger than 2.5 µm (large size) from a DC 1700 were compared with the 1-min averages of PM2.5 (aerodynamic size less than 2.5 µm) and coarse PM (aerodynamic size between 2.5 and 10 µm) concentrations from a Grimm 11-R. We used a linear regression equation to convert DC 1700 number concentrations to mass concentrations, utilizing measurements from the Grimm 11-R. The estimated average DC 1700 PM2.5 concentration (13.2 ± 13.7 µg/m3) was similar to the average measured Grimm 11-R PM2.5 concentration (11.3 ± 15.1 µg/m3). The overall correlation (r2) for PM2.5 between the DC 1700 and Grimm 11-R was 0.778. The estimated average coarse PM concentration from the DC 1700 (5.6 ± 12.1 µg/m3) was also similar to that measured with the Grimm 11-R (4.8 ± 16.5 µg/m3) with an r2 of 0.481. The effects of relative humidity and particle size on the association between the DC 1700 and the Grimm 11-R results were also examined. The calculated PM mass concentrations from the DC 1700 were close to those measured with the Grimm 11-R when relative humidity was less than 60% for both PM2.5 and coarse PM. Particle size distribution was more important for the association of coarse PM between the DC 1700 and Grimm 11-R than it was for PM2.5.Implications: The performance of a low-cost particulate matter (PM) sensor was evaluated in an urban residential area. Both PM2.5 and coarse PM (PM10-2.5) mass concentrations were estimated using a DC1700 PM sensor. The calculated PM mass concentrations from the number concentrations of DC 1700 were close to those measured with the Grimm 11-R when relative humidity was less than 60% for both PM2.5 and coarse PM. Particle size distribution was more important for the association of coarse PM between the DC 1700 and Grimm 11-R than it was for PM2.5.

On the AOD contribution to ground PM prediction models

Introduction. The use of satellite observations for estimating ground level particulate matter (PM) concentrations is growing. Specifically, numerous researchers use satellite-based Aerosol Optical Depth (AOD) as an explanatory variable in different statistical models for estimating PM concentrations. Whereas some models use only the AOD, others use additional variables, such as meteorological, environmental, and land use variables. AOD measures light extinction at a given wavelength due to scattering and absorption along the measured atmospheric column. The rationale behind using the AOD stems from the physical interaction of airborne PM with electromagnetic radiation, and since it has a much better spatial coverage than ground PM measurements. In many works AOD is the primary variable in spite of the coarse temporal resolution of the MODIS-based AOD (once per day) and the large number of missing data due to clouds. Methods. This work assesses the actual contribution of AOD to PM estimations by analyzing (a) a large database of fine and coarse PM concentrations from different geographic locations, (b) satellite-borne AOD obtained with different spatial grid by applying different algorithms on MODIS raw data, and (c) applying various statistical models to link these databases. Results. We found that the date, as a variable, has a crucial effect on the performance of all the models, including mixed effects models (MEM) that consistently result in better predictions. In fact, the seemingly higher explained spatiotemporal variability of MEMs results from the model fitting the temporal PM patterns, for which the date is a strong predictor. Surprisingly, the overall AOD contribution to the explained variability is little. Conclusion. While AOD has a lot of potential for PM estimation in locations where monitoring is very sparse or not existing at all, currently its actual contribution to predicted PM levels is marginal, and should be further studied.

Abstract P059: Telemedicine Data Indicate Short-term Associations Between Clinical Cardiovascular Events and Ambient Particulate Air Pollution

Introduction: Particulate matter (PM) air pollution has been linked to cardiovascular morbidity and mortality with large public health burdens. Although associations between PM and subclinical autonomic and vascular changes have been shown to occur within minutes to hours, studies have been limited in their ability to investigate such short time scales for clinical cardiac events. Accurate onset time is essential for risk estimation of such short exposures, but publically available data lack this information. This study utilized unique telemedicine data to more accurately estimate the short-term effects of PM exposure in triggering acute cardiac events. Hypothesis: We assessed the hypothesis that elevated short-term (1-24 hours) concentrations of coarse PM (2.5 to 10 μm in aerodynamic diameter, PM 10-2.5 ) and fine PM ( &lt; 2.5 μm, PM 2.5 ) in two metropolitan areas in Israel are associated with an increased risk of clinical cardiac events. Methods: We conducted a time-stratified case-crossover study in which cardiac events were identified using time-resolved telemedicine data from the Tel Aviv and Haifa areas, Israel, between 2002 and 2013. Calls to the telemedicine service for cardiac-related symptoms that resulted in an in-home examination by a mobile intensive care and transfer to a hospital were classified into ischemic, arrhythmia, or non-specific events. Onset time was determined by the time of a medical phone call. Ambient pollutant concentrations measured at central monitoring stations were compared between case and control periods using multivariate conditional logistic regression after adjusting for meteorology and other risk factors. We further explored sensitivity for certainty of diagnosis and effect modification by personal characteristics. Results: A total of 7,617 telemedicine subscribers reported 12,661 (20% ischemic, 31% arrhythmic and 49% non-specific) cardiac events that resulted in an evacuation to a hospital over our 12 year period. After adjustment for confounders, a 10 μg/m 3 higher PM 10-2.5 concentration was associated with a greater odds of a clinical cardiac event, with the strongest associations for events due to arrhythmia (OR 1.006, 95% CI: 1.001-1.011) within 12 hours. Similar associations were found at other time points, for ischemic and non-specific cardiac events, as well as for PM 2.5 but these associations often had wider confidence intervals. Risks tended to be higher for subjects who had diabetes, previous ischemic heart disease or were obese, although these differences did not achieve statistical significance. Conclusions: Exposure to PM air pollution over the course of hours may increase the risk of acute clinical cardiac events. Telemedicine allows for more accurate information on event onset and thus can be a powerful tool for epidemiologic studies focusing on short-term exposures to environmental or other stressors.

Coarse particulate matter and emergency ambulance dispatches in Fukuoka, Japan: a time-stratified case-crossover study.

There is no conclusive evidence of adverse health effects caused by short-term exposure to coarse particulate matter, so in this case-crossover study we looked for an association between exposure and emergency ambulance dispatches (as a proxy of acute health outcomes). We used data on emergency ambulance dispatches in Fukuoka City, Japan between 2005 and 2010. After excluding ambulance dispatches related to external injuries and pregnancy/childbirth, we analyzed data on 176,123 dispatches. Citywide daily mean concentrations of suspended particulate matter (SPM) and fine particulate matter (PM2.5) were calculated from ambient monitoring data, and the differences between concentrations of SPM and PM2.5 were used as an exposure surrogate of coarse particulate matter. Using a conditional logistic regression model, we estimated the ambient temperature and relative humidity adjusted odds ratios (ORs) per 10 μg/m(3) increase in coarse particulate matter. The average daily concentration of coarse particulate matter over the study period was 9.9 μg/m(3), representing 33% of the total concentration of SPM. Elevated concentrations of coarse particulate matter were associated with an increase in respiratory disease-related emergency ambulance dispatches for adults aged 65 years or older (9,716 dispatches, OR for lag0-1 = 1.065, 95% confidence interval = 1.023-1.109). After additional adjustment for exposure to PM2.5, we observed a statistically non-significant increased risk (OR = 1.035, 0.986-1.086). We found weak evidence of adverse effects of short-term exposure to coarse particulate matter on human health.