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1.
During the last 10 years, high atmospheric concentrations of airborne particles recorded in the Mexico City metropolitan area have caused concern because of their potential harmful effects on human health. Four monitoring campaigns have been carried out in the Mexico City metropolitan area during 2000-2002 at three sites: (1) Xalostoc, located in an industrial region; (2) La Merced, located in a commercial area; and (3) Pedregal, located in a residential area. Results of gravimetric and chemical analyses of 330 samples of particulate matter (PM) with an aerodynamic diameter less than 2.5 microm (PM2.5) and PM with an aerodynamic diameter less than 10 microm (PM10) indicate that (1) PM2.5/PM10 average ratios were 0.42, 0.46, and 0.52 for Xalostoc, La Merced, and Pedregal, respectively; (2) the highest PM2.5 and PM10 concentrations were found at the industrial site; (3) PM2.5 and PM10 concentrations were lower at nighttime; (4) PM2.5 and PM10 spatial averages concentrations were 35 and 76 microg/m3, respectively; and (5) when the PM2.5 standard was exceeded, nitrate, sulfate, ammonium, organic carbon, and elemental carbon concentrations were high. Twenty-four hour averaged PM2.5 concentrations in Mexico City and Sao Paulo were similar to those recorded in the 1980s in Los Angeles. PM10 concentrations were comparable in Sao Paulo and Mexico City but 3-fold lower than those found in Santiago. 相似文献
2.
PM 10 levels of the 16 US-EPA Priority Pollutant polycyclic aromatic hydrocarbons (PAHs) were measured from March 17 to 31, 2003, in 8-h time bins (morning, afternoon and nighttime) at Merced, a source site dominated by vehicular traffic emissions near the center of Mexico City, and at Pedregal, a receptor area located downwind in a residential area of low traffic. Along with PAH, elemental (EC) and organic carbon (OC), mass, and prevailing meteorological parameters were measured. At the source location, measured concentrations of benzo[ a]pyrene (BAP), an agent suspected of being carcinogenic to humans and of causing oxidative DNA damage, reached concentrations as high as 2.04 and 2.11 ng m ?3 during the morning of a weekday and the night period of a holiday. Compared with source dominated areas in Central Los Angeles, the BAP levels found in Central Mexico City are approximately 6 times higher. Benzo[ ghi]perylene (BGP) levels were, in general, the highest among the target PAH, both at the source (7.2 ng m ?3) and the receptor site (2.8 ng m ?3), suggesting that, at both locations, exhaust emission by light-duty (LD) vehicles is an important contributor to the atmospheric PAH burden. Higher PAH concentrations were observed during the morning period (5:00–13:00 h) at the source and the receptor site. The concentrations of PAHs found predominantly in the particle-phase (MW > 202) correlated well ( r = 0.57–0.71) with the occurrence of surface thermal inversions and with mixing heights ( r = ?0.57 to ?0.72). Organic and elemental carbon ratios also indicated that Pedregal is impacted by secondary aerosols during the afternoon hours. 相似文献
3.
Abstract In 1997, Maryland had no available ambient Federal Reference Method data on particulate matter less than 2.5 μm in aerodynamic diameter (PM 2.5), but did have annual ambient data for PM smaller than 10 μm (PM 10) at 24 sites. The PM 10 data were analyzed in conjunction with local annual and seasonal zip-code-level emission inventories and with speciated PM 2.5 data from four nearby monitors in the IMPROVE network (located in the national parks, wildlife refuges, and wilderness areas) in an effort to estimate annual average and seasonal high PM 2.5 concentrations at the 24 PM 10 monitor sites operating from 1992 to 1996. All seasonal high concentrations were estimated to be below the 24-hr PM 2.5 National Ambient Air Quality Standards (NAAQS) at the sites operating in Maryland between 1992 and 1996. The estimates also indicated that 12 monitor sites might exceed the 3-year annual average PM 2.5 NAAQS of 15 ug/m 3, but Maryland’s air quality shows signs that it has been improving since 1992. The estimates also were compared with actual measurements after the PM 2.5 monitor network was installed. The estimates were adequate for describing the chemical composition of the PM 2.5, forecasting compliance status with the 24-hr and annual standards, and determining the spatial variations in PM 2.5 across central Maryland. 相似文献
4.
Abstract This paper presents the results of the first reported study on fine particulate matter (PM) chemical composition at Salamanca, a highly industrialized urban area of Central Mexico. Samples were collected at six sites within the urban area during February and March 2003. Several trace elements, organic carbon (OC), elemental carbon (EC), and six ions were analyzed to characterize aerosols. Average concentrations of PM with aerodynamic diameter of less than 10 μm (PM 10) and fine PM with aerodynamic diameter of less than 2.5 μm (PM 2.5) ranged from 32.2 to 76.6 μg m -3 and 11.1 to 23.7 μg m -3, respectively. OC (34%), SO 4 = (25.1%), EC (12.9%), and geological material (12.5%) were the major components of PM 2.5. For PM 10, geological material (57.9%), OC (17.3%), and SO 4 = (9.7%) were the major components. Coarse fraction (PM 10 –PM 2.5), geological material (81.7%), and OC (8.6%) were the dominant species, which amounted to 90.4%. Correlation analysis showed that sulfate in PM 2.5 was present as ammonium sulfate. Sulfate showed a significant spatial variation with higher concentrations to the north resulting from predominantly southwesterly winds above the surface layer and by major SO 2 sources that include a power plant and refinery. At the urban site of Cruz Roja it was observed that PM 2.5 mass concentrations were similar to the submicron fraction concentrations. Furthermore, the correlation between EC in PM 2.5 and EC measured from an aethalometer was r 2 = 0.710. Temporal variations of SO 2 and nitrogen oxide were observed during a day when the maximum concentration of PM 2.5 was measured, which was associated with emissions from the nearby refinery and power plant. From cascade impactor measurements, the three measured modes of airborne particles corresponded with diameters of 0.32, 1.8, and 5.6 μm. 相似文献
5.
ABSTRACT The main goal of this study was to evaluate the magnitude of outdoor exposure to fine particulate matter (PM 10) potentially experienced by the population of metropolitan Mexico City. With the use of a geographic information system (GIS), spatially resolved PM 10 distributions were generated and linked to the local population. The PM 10 concentration exceeded the 24-hr air quality standard of 150 μg/m 3 on 16% of the days, and the annual air quality standard of 50 μg/m 3 was exceeded by almost twice its value in some places. The basic methodology described in this paper integrates spatial demographic and air quality databases, allowing the evaluation of various air pollution reduction scenarios. Achieving the annual air quality standard would represent a reduction in the annual arithmetic average concentration of 14 μg/m 3 for the typical inhabitant. Human exposure to particulate matter (PM) has been associated with mortality and morbidity in Mexico City; reducing the concentration levels of this pollutant would represent a reduction in mortality and morbidity and the associated cost of such impacts. This methodology is critical to assessing the potential benefits of the current initiative to improve air quality implemented by the Environmental Metropolitan Commission of Mexico City. 相似文献
6.
Abstract Twenty-five MiniVol samplers were operated throughout the Mexico City metropolitan region from February 22 through March 22, 1997, to evaluate the variability of PM 10 concentrations and composition. The highest PM 10 concentrations were found in neighborhoods with unpaved or dirty roads, and elements related to crustal material were the main cause of differences from nearby (<200 m) monitors that were not adjacent to the roadbed. SO 4 2?concentrations were homogeneous across the city. SO 4 2?measured at the city boundaries was about two-thirds of the concentrations measured within the urbanized area, indicating that most SO 4 2? is of regional origin. Elemental carbon (EC) and organic carbon (OC) concentrations were highly variable, with higher concentrations in areas that had high diesel traffic and older vehicles. Spatial correlations among PM 10 concentrations were high, even though absolute concentrations were variable, indicating a common effect of meteorology on the concentration or dispersion of local emissions. 相似文献
7.
The PM 10, PM 2.5, and PM 1 (particulate matter with aerodynamic diameters <10, <2.5, and <1 μm, respectively) concentrations were monitored over a 90-day period in a naturally ventilated school building located at roadside in Chennai City. The 24-hr average PM 10, PM 2.5, and PM 1 concentrations at indoor and outdoor environments were found to be 136 ± 60, 36 ± 15, and 20 ± 12 and 76 ± 42, 33 ± 16, and 23 ± 14 μg/m 3, respectively. The size distribution of PM in the classroom indicated that coarse mode was dominant during working hours (08:00 a.m. to 04:00 p.m.), whereas fine mode was dominant during nonworking hours (04:00 p.m. to 08:00 a.m.). The increase in coarser particles coincided with occupant activities in the classrooms and finer particles were correlated with outdoor traffic. Analysis of indoor PM 10, PM 2.5, and PM 1 concentrations monitored at another school, which is located at urban reserved forest area (background site) indicated 3–4 times lower PM 10 concentration than the school located at roadside. Also, the indoor PM 1 and PM 2.5 concentrations were 1.3–1.5 times lower at background site. Further, a mass balance indoor air quality (IAQ) model was modified to predict the indoor PM concentration in the classroom. Results indicated good agreement between the predicted and measured indoor PM 2.5 ( R2 = 0.72–0.81) and PM 1 ( R2 = 0.81–0.87) concentrations. But, the measured and predicted PM 10 concentrations showed poor correlation ( R2 = 0.17–0.23), which may be because the IAQ model could not take into account the sudden increase in PM 10 concentration (resuspension of large size particles) due to human activities. Implications:The present study discusses characteristics of the indoor coarse and fine PM concentrations of a naturally ventilated school building located close to an urban roadway and at a background site in Chennai City, India. The study results will be useful to engineers and policymakers to prepare strategies for improving the IAQ inside classrooms. Further, this study may help in the development of IAQ standards and guidelines in India. 相似文献
8.
This study attempts to determine the influence of air quality in a residential area near a medical waste incineration plant. Ambient air concentrations of polycyclic aromatic hydrocarbons (PAHs), PM 10 and PM 2.5 (PM—particulate matter) were determined by collecting air samples in areas both upwind and downwind of the plant. The differences in air pollutant levels between the study area and a reference area 11 km away from the plant were evaluated.Dichotomous samplers were used for sampling PM 2.5 and PM 10 from ambient air. Two hundred and twenty samples were obtained from the study area, and 100 samples were taken from a reference area. Samples were weighed by an electronic microbalance and concentrations of PM 2.5 and PM 10 were determined. A HPLC equipped with a fluorescence detector was employed to analyze the concentrations of 15 PAHs compounds adsorbed into PM 2.5 and PM 10.The experimental results indicated that the average concentrations of PM 2.5 and PM 10 were 30.34±17.95 and 36.81±20.45 μg m −3, respectively, in the study area, while the average ratio of PM 2.5/PM 10 was 0.82±0.01. The concentrations of PM 2.5 and PM 10 of the study area located downwind of the incinerator were significantly higher than the study area upwind of the incinerator ( P<0.05).The concentration of PAHs in PM 2.5 in the study area was 2.2 times higher than in the reference area ( P<0.05). Furthermore, the benzo( a)pyrene concentrations in PM 2.5 and PM 10 were 0.11±0.05 ng m −3 and 0.12±0.06 ng m −3 in the study area, respectively. The benzo( a)pyrene concentrations of PM 2.5 and PM 10 in the study area were 7 and 5.3 times higher than in the reference area ( P<0.05), respectively.The study indicated that the air quality of PM 2.5, PM 10 and PAHs had significant contamination by air pollutants emitted from a medical waste incineration factory, representing a public health problem for nearby residences, despite the factory being equipped with a modern air pollution control system. 相似文献
9.
Abstract Although the fugitive dust associated with construction mud/dirt carryout can represent a substantial portion of the particulate matter (PM) emissions inventory in non-attainment areas, it has not been well characterized by direct sampling methods. In this paper, a research program is described that directly determined both PM 10 and PM 2.5 (particles ≤10 and 2.5 μm in classical aerodynamic diameter, respectively) emission factors for mud/dirt carryout from a major construction project located in metropolitan Kansas City, MO. The program also assessed the contribution of automotive emissions to the total PM 2.5 burden and determined the baseline emissions from the test road. As part of the study, both time-integrated and continuous exposure-profiling methods were used to assess the PM emissions, including particle size and elemental composition. This research resulted in overall PM 10 and PM 2.5 emission factors of 6 and 0.2 g/vehicle, respectively. Although PM 10 is within the range of prior U.S. Environmental Protection Agency (EPA) guidance, the PM 2.5 emission factor is far lower than previous estimates published by EPA. In addition, based on both the particle size and chemical data obtained in the study, a major portion of the PM 2.5 emissions appears to be attributable to automotive exhaust from light-duty, gasoline-powered vehicles and not to the fugitive dust associated with re-entrained mud/dirt carryout. 相似文献
10.
Many individuals work outdoors in the formal and informal economy of the large urban areas in developing countries, where they are potentially exposed for long periods to high concentrations of ambient airborne particulate matter (PM). This study describes the personal exposures to PM of 2.5 μm aerodynamic diameter and smaller (PM 2.5) for a sample of outdoor and indoor workers in two cities, Mexico City and Puebla, in central Mexico.Thirty-six workers in Mexico City and 17 in Puebla were studied. Thirty were outdoor workers (i.e., taxi and bus drivers, street vendors, and vehicle inspectors) and 23 were indoor (office) workers. Their personal exposures to PM 2.5 were monitored for a mean 19-h period. In Mexico City, the street vendors and taxi drivers overall exposures were significantly higher than indoor workers were. In Puebla, bus drivers had a higher overall exposure than vehicle inspectors or indoor workers. Most of the exposures were above the 65 μg m −3 24-h Mexican standard.In Mexico City, exposures to Si, Ti, Cr, Mn, Fe, Ni, Cu, Mo and Cd were higher for outdoor than for indoor workers. In Puebla, exposures to Si, S, K, Ca, Ti, V, Mn, and Zn also were higher for outdoor workers. In Mexico City outdoor workers exposures to Cu, Pb, Cr, Se and Mo were 4 or more times higher than for Puebla outdoor workers, while Puebla outdoor workers’ exposures to V, Si, Fe and Ca were 3 or more times higher than Mexico City outdoor workers.These results suggest that for these outdoor workers the elevated local ambient air PM concentrations and an extended period spent outside are more important contributors to total exposures than indoor concentrations. These workers could be at particular risk of increased morbidity and mortality associated with ambient PM. 相似文献
11.
Abstract One-hour average ambient concentrations of particulate matter (PM) with an aerodynamic diameter <2.5 μm (PM 2.5) were determined in Steubenville, OH, between June 2000 and May 2002 with a tapered element oscillating microbalance (TEOM). Hourly average gaseous copollutant [carbon monoxide (CO), sulfur dioxide (SO 2), nitrogen oxide (NO x), and ozone (O 3)] concentrations and meteorological conditions also were measured. Although 75% of the 14,682 hourly PM 2.5 concentrations measured during this period were ≤17 μg/m 3, concentrations >65 μg/m 3 were observed 76 times. On average, PM 2.5 concentrations at Steubenville exhibited a diurnal pattern of higher early morning concentrations and lower afternoon concentrations, similar to the diurnal profiles of CO and NO x. This pattern was highly variable; however, PM 2.5 concentrations >65 μg/m 3 were never observed during the mid-afternoon between 1:00 p.m. and 5:00 p.m. EST. Twenty-two episodes centered on one or more of these elevated concentrations were identified. Five episodes occurred during the months June through August; the maximum PM 2.5 concentration during these episodes was 76.6 μg/m 3. Episodes occurring during climatologically cooler months often featured higher peak concentrations (five had maximum concentrations between 95.0 and 139.6 μg/m 3), and many exhibited strong covariation between PM 2.5 and CO, NO x, or SO 2. Case studies suggested that nocturnal surface-based temperature inversions were influential in driving high nighttime concentrations of these species during several cool season episodes, which typically had dramatically lower afternoon concentrations. These findings provide insights that may be useful in the development of PM 2.5 reduction strategies for Steubenville, and suggest that studies assessing possible health effects of PM 2.5 should carefully consider exposure issues related to the intraday timing of PM 2.5 episodes, as well as the potential for toxicological interactions among PM 2.5 and primary gaseous pollutants. 相似文献
12.
Abstract Data from the U.S. Environmental Protection Agency's Aerometric Information Retrieval System (now known as the Air Quality System) database for 1999 and 2000 have been used to characterize the spatial variability of concentrations of particulate matter with aerodynamic diameter ≤2.5 μg (PM 2.5) in 27 urban areas across the United States. Different measures were used to quantify the degree of uniformity of PM 2.5 concentrations in the urban areas characterized. It was observed that PM 2.5 concentrations varied to differing degrees in the urban areas examined. Analyses of several urban areas in the Southeast indicated high correlations between site pairs and spatial uniformity in concentration fields. Considerable spatial variation was found in other regions, especially in the West. Even within urban areas in which all site pairs were highly correlated, a variable degree of heterogeneity in PM 2.5 concentrations was found. Thus, even though concentrations at pairs of sites were highly correlated, their concentrations were not necessarily the same. These findings indicate that the potential for exposure misclassification errors in time-series epidemiologic studies exists. 相似文献
13.
ABSTRACT Measurements of 15-min average PM 2.5 concentrations were made with a real-time light-scattering instrument at both outdoor (central monitoring sites in three communities) and indoor (residential) locations over two seasons in the Minneapolis-St. Paul metropolitan area. These data are used to examine within-day variability of PM 2.5 concentrations indoors and outdoors, as well as matched indoor-to-outdoor (I/O) ratios. Concurrent gravimetric measurements of 24-hr average PM 2.5 concentrations were also obtained as a way to compare real-time measures with this more traditional metric. Results indicate that (1) within-day variability for both indoor and outdoor 15-min average PM 2.5 concentrations was substantial and comparable in magnitude to day-to-day variability for 24hr average concentrations; (2) some residences exhibited substantial variability in indoor aerosol characteristics from one day to the next; (3) peak values for indoor short-term (15-min) average PM 2.5 concentrations routinely exceeded 24-hr average outdoor values by factors of 3-4; and (4) relatively strong correlations existed between indoor and outdoor PM 2.5 concentrations for both 24-hr and 15-min averages. 相似文献
14.
The 24-h average coarse (PM 10) and fine (PM 2.5) fraction of airborne particulate matter (PM) samples were collected for winter, summer and monsoon seasons during November 2008-April 2009 at an busy roadside in Chennai city, India. Results showed that the 24-h average ambient PM 10 and PM 2.5 concentrations were significantly higher in winter and monsoon seasons than in summer season. The 24-h average PM 10 concentration of weekdays was significantly higher (12-30%) than weekends of winter and monsoon seasons. On weekends, the PM 2.5 concentration was found to slightly higher (4-15%) in monsoon and summer seasons. The chemical composition of PM 10 and PM 2.5 masses showed a high concentration in winter followed by monsoon and summer seasons.The U.S.EPA-PMF (positive matrix factorization) version 3 was applied to identify the source contribution of ambient PM 10 and PM 2.5 concentrations at the study area. Results indicated that marine aerosol (40.4% in PM 10 and 21.5% in PM 2.5) and secondary PM (22.9% in PM 10 and 42.1% in PM 2.5) were found to be the major source contributors at the study site followed by the motor vehicles (16% in PM 10 and 6% in PM 2.5), biomass burning (0.7% in PM 10 and 14% in PM 2.5), tire and brake wear (4.1% in PM 10 and 5.4% in PM 2.5), soil (3.4% in PM 10 and 4.3% in PM 2.5) and other sources (12.7% in PM 10 and 6.8% in PM 2.5). 相似文献
15.
Several studies indicate that mortality and morbidity can be well correlated to atmospheric aerosol concentrations with aerodynamic diameter less than 2.5 µm (PM 2.5). In this work the PM 2.5 at Recife city was analyzed as part of a main research project (INAIRA) to evaluate the air pollution impact on human health in six Brazilian metropolitan areas. The average concentration, for 309 samples (24-hr), from June 2007 to July 2008, was 7.3 µg/m³, with an average of 1.1 µg/m³ of black carbon. The elemental concentrations of samples were obtained by x-ray fluorescence. The concentrations were then used for characterizing the aerosol, and also were employed for receptor modelling to identify the major local sources of PM 2.5. Positive matrix factorization analysis indicated six main factors, with four being associated to soil dust, vehicles and sea spray, metallurgical activities, and biomass burning, while for a chlorine factor, and others related to S, Ca, Br, and Na, we could make no specific source association. Principal component analysis also indicated six dominant factors, with some specific characteristics. Four factors were associated to soil dust, vehicles, biomass burning, and sea spray, while for the two others, a chlorine- and copper-related factor and a nickel-related factor, it was not possible to do a specific source association. The association of the factors to the likely sources was possible thanks to meteorological analysis and sources information. Each model, although giving similar results, showed factors’ peculiarities, especially for source apportionment. The observed PM 2.5 concentration levels were acceptable, notwithstanding the high urbanization of the metropolitan area, probably due to favorable conditions for air pollution dispersion. More than a valuable historical register, these results should be very important for the next analysis, which will correlate health data, PM 2.5 levels, and sources contributions in the context of the six studied Brazilian metropolises. Implications: The analysis of fine particulate matter (PM 2.5) in Recife city, Brazil, gave a significant picture of the local concentration and composition of this pollutant, which exhibits robust associations to adverse human health effects. Data from 1 year of sampling evaluated the seasonal variability and its connections with weather patterns. Source apportionment in this metropolitan area was obtained based in a combination of receptor models: principal component analysis (PCA)/chemical mass balance (CMB) and positive matrix factorization (PMF). These results give guidelines for local air pollution control actions, providing significant information for a health study in the context of establishing a new national air pollution protocol based on Brazilian cities data. 相似文献
16.
ABSTRACT The chemical mass balance (CMB) model was applied to winter (November through January) 1991–1996 PM2.5 and PM10 data from the Sacramento 13th and T Streets site in order to identify the contributions from major source categories to peak 24-hr ambient PM 2.5 and PM 10 levels. The average monthly PM 10 monitoring data for the nine-year period in Sacramento County indicate that elevated concentrations are typical in the winter months. Concentrations on days of highest PM 10 are dominated by the PM2.5 fraction. One factor contributing to increased PM 2.5 concentrations in the winter is meteorology (cool temperatures, low wind speeds, low inversion layers, and more humid conditions) that favors the formation of secondary nitrate and sulfate aerosols. Residential wood burning also elevates fine particulate concentrations in the Sacramento area. The results of the CMB analysis highlight three key points. First, the source apportionment results indicate that primary motor vehicle exhaust and wood smoke are significant sources of both PM 2.5 and PM 10 in winter. Second, nitrates, secondarily formed as a result of motor-vehicle and other sources of nitrogen oxide (NO x), are another principal cause of the high PM 2.5 and PM 10 levels during the winter months. Third, fugitive dust, whether it is resuspended soil and dust or agricultural tillage, is not the major contributor to peak winter PM 2.5 and PM10 levels in the Sacramento area. 相似文献
18.
Indoor particulate matter samples were collected in 17 homes in an urban area in Alexandria during the summer season. During air measurement in all selected homes, parallel outdoor air samples were taken in the balconies of the domestic residences. It was found that the mean indoor PM 2.5 and PM 10 (particulate matter with an aerodynamic diameter ≤2.5 and ≤10 μm, respectively) concentrations were 53.5 ± 15.2 and 77.2 ± 15.1 µg/m 3, respectively. The corresponding mean outdoor levels were 66.2 ± 16.5 and 123.8 ± 32.1 µg/m 3, respectively. PM 2.5 concentrations accounted, on average, for 68.8 ± 12.8% of the total PM 10 concentrations indoors, whereas PM 2.5 contributed to 53.7 ± 4.9% of the total outdoor PM 10 concentrations. The median indoor/outdoor mass concentration (I/O) ratios were 0.81 (range: 0.43–1.45) and 0.65 (range: 0.4–1.07) for PM 2.5 and PM 10, respectively. Only four homes were found with I/O ratios above 1, indicating significant contribution from indoor sources. Poor correlation was seen between the indoor PM 10 and PM 2.5 levels and the corresponding outdoor concentrations. PM 10 levels were significantly correlated with PM 2.5 loadings indoors and outdoors and this might be related to PM 10 and PM 2.5 originating from similar particulate matter emission sources. Smoking, cooking using gas stoves, and cleaning were the major indoor sources contributed to elevated indoor levels of PM 10 and PM 2.5. Implications: The current study presents results of the first PM 2.5 and PM 10 study in homes located in the city of Alexandria, Egypt. Scarce data are available on indoor air quality in Egypt. Poor correlation was seen between the indoor and outdoor particulate matter concentrations. Indoor sources such as smoking, cooking, and cleaning were found to be the major contributors to elevated indoor levels of PM 10 and PM 2.5. 相似文献
19.
Long-term exposure to particular matter (PM), especially fine PM (< 2.5 μm in the aerodynamic diameter, PM2.5), is associated with increased risk of cardiovascular disorders. This study aimed to evaluate the association between long-term exposure to PM2.5/PM10 and the metabolic change in the plasma. Specifically, using metabolomics, we sought to identify the biomarkers for the vulnerable subgroup to PM2.5 exposure. A total of 78 college student volunteers were recruited into this prospective cohort study. All participants received 8 rounds of physical examinations at twice quarterly. Air purifiers were placed in 40 of 78 participants’ dormitories for 14 days. Before and after intervention, physical examinations were performed and the peripheral blood was collected. Plasma metabolomics was determined by ultra-performance liquid chromatography-mass spectrometry. During the follow-up, the average concentrations of PM2.5 and PM10 were 53 μg/m3 and 93 μg/m3, respectively. Totally, 42 and 120 differential metabolic features were detected for PM10 and PM2.5 exposure, respectively. In total, 25 differential metabolites were identified for PM2.5 exposure, most of which were phospholipids. No distinctive metabolites were found for PM10 exposure. A total of 6 differential metabolites (lysoPC (P-20:0), lysoPC (P-18:1(9z)), lysoPC (20:1), lysoPC (O-16:0), choline, and found 1,3-diphenylprop-2-en-1-one) were characterized and confirmed for sensitive individuals. Importantly, we found LysoPC (P-20:0) and LysoPC (P-18:1(9z)) changed significantly before and after air purifier intervention. Our results indicated that the phospholipid catabolism was involved in long-term PM2.5 exposure. LysoPC (P-20:0) and LysoPC (P-18:1(9z)) may be the biomarkers of PM2.5 exposure. 相似文献
20.
This study provides the first comprehensive analysis of the seasonal variations and weekday/weekend differences in fine (aerodynamic diameter <2.5 μm; PM 2.5) and coarse (aerodynamic diameter 2.5–10 μm; PM 2.5–10) particulate matter mass concentrations, elemental constituents, and potential source origins in Jeddah, Saudi Arabia. Air quality samples were collected over 1 yr, from June 2011 to May 2012 at a frequency of three times per week, and analyzed. The average mass concentrations of PM 2.5 (21.9 μg/m 3) and PM 10 (107.8 μg/m 3) during the sampling period exceeded the recommended annual average levels by the World Health Organization (WHO) for PM 2.5 (10 μg/m 3) and PM 10 (20 μg/m 3), respectively. Similar to other Middle Eastern locales, PM 2.5–10 is the prevailing mass component of atmospheric particulate matter at Jeddah, accounting for approximately 80% of the PM 10 mass. Considerations of enrichment factors, absolute principal component analysis (APCA), concentration roses, and backward trajectories identified the following source categories for both PM 2.5 and PM 2.5–10: (1) soil/road dust, (2) incineration, and (3) traffic; and for PM 2.5 only, (4) residual oil burning. Soil/road dust accounted for a major portion of both the PM 2.5 (27%) and PM 2.5–10 (77%) mass, and the largest source contributor for PM 2.5 was from residual oil burning (63%). Temporal variations of PM 2.5–10 and PM 2.5 were observed, with the elevated concentration levels observed for mass during the spring (due to increased dust storm frequency) and on weekdays (due to increased traffic). The predominant role of windblown soil and road dust in both the PM 2.5 and PM 2.5–10 masses in this city may have implications regarding the toxicity of these particles versus those in the Western world where most PM health assessments have been made in the past. These results support the need for region-specific epidemiological investigations to be conducted and considered in future PM standard setting. Implications: Temporal variations of fine and coarse PM mass, elemental constituents, and sources were examined in Jeddah, Saudi Arabia, for the first time. The main source of PM2.5–10 is natural windblown soil and road dust, whereas the predominant source of PM2.5 is residual oil burning, generated from the port and oil refinery located west of the air sampler, suggesting that targeted emission controls could significantly improve the air quality in the city. The compositional differences point to a need for health effect studies to be conducted in this region, so as to directly assess the applicability of the existing guidelines to the Middle East air pollution. 相似文献
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