共查询到20条相似文献,搜索用时 781 毫秒
1.
Abstract Airborne fine particles of PM 2.5-10 and PM 2.5 in Bangkok, Nonthaburi, and Ayutthaya were measured from December 22, 1998, to March 26, 1999, and from November 30, 1999, to December 2, 1999. Almost all the PM 10 values in the high-polluted ( H) area exceeded the Thailand National Ambient Air Quality Standards (NAAQS) of 120 μg/m 3. The low-polluted ( L) area showed low PM 10 (34–74 μg/m 3 in the daytime and 54–89 μg/m 3 at night). PM 2.5 in the H area varied between 82 and 143 μg/m 3 in the daytime and between 45 and 146 μg/m 3 at night. In the L area, PM 2.5 was quite low both day and night and varied between 24 and 54 μg/m 3, lower than the U.S. Environmental Protection Agency (EPA) standard (65 μg/m 3). The personal exposure results showed a significantly higher proportion of PM 2.5 to PM 10 in the H area than in the L area ( H = 0.80 ± 0.08 and L = 0.65 ± 0.04). Roadside PM 10 was measured simultaneously with the Thailand Pollution Control Department (PCD) monitoring station at the same site and at the intersections where police work. The result from dual simultaneous measurements of PM 10 showed a good correlation (correlation coefficient: r = 0.93); however, PM levels near the roadside at the intersections were higher than the concentrations at the monitoring station. The relationship between ambient PM level and actual personal exposures was examined. Correlation coefficients between the general ambient outdoors and personal exposure levels were 0.92 for both PM 2.5 and PM 10. Bangkok air quality data for 1997–2000, including 24-hr average PM 10, NO 2, SO 2, and O 3 from eight PCD monitoring stations, were analyzed and validated. The annual arithmetic mean PM 10 of the PCD data at the roadside monitoring stations for the last 3 years decreased from 130 to 73 μg/m 3, whereas the corresponding levels at the general monitoring stations decreased from 90 to 49 μg/m 3. The proportion of days when the level of the 24-hr average PM 10 exceeded the NAAQS was between 13 and 26% at roadside stations. PCD data showed PM 10 was well correlated with NO 2 but not with SO 2, suggesting that automobile exhaust is the main source of the particulate air pollution. The results obtained from the simultaneous measurement of PM 2.5 and PM 10 indicate the potential environmental health hazard of fine particles. In conclusion, Bangkok traffic police were exposed to high levels of automobile-derived particulate air pollution. 相似文献
2.
This paper reports findings from a case study designed to investigate indoor and outdoor air quality in homes near the United States–Mexico border. During the field study, size-resolved continuous particulate matter (PM) concentrations were measured in six homes, while outdoor PM was simultaneously monitored at the same location in Nogales, Sonora, Mexico, during March 14–30, 2009. The purpose of the experiment was to compare PM in homes using different fuels for cooking, gas versus biomass, and to obtain a spatial distribution of outdoor PM in a region where local sources vary significantly (e.g., highway, border crossing, unpaved roads, industry). Continuous PM data were collected every 6 seconds using a valve switching system to sample indoor and outdoor air at each home location. This paper presents the indoor PM data from each home, including the relationship between indoor and outdoor PM. The meteorological conditions associated with elevated ambient PM events in the region are also discussed. Results indicate that indoor air pollution has a strong dependence on cooking fuel, with gas stoves having hourly averaged median PM 3 concentrations in the range of 134 to 157 μg m ?3 and biomass stoves 163 to 504 μg m ?3. Outdoor PM also indicates a large spatial heterogeneity due to the presence of microscale sources and meteorological influences (median PM 3: 130 to 770 μg m ?3). The former is evident in the median and range of daytime PM values (median PM 3: 250 μg m ?3, maximum: 9411 μg m ?3), while the meteorological influences appear to be dominant during nighttime periods (median PM 3: 251 μg m ?3, maximum: 10,846 μg m ?3). The atmospheric stability is quantified for three nighttime temperature inversion episodes, which were associated with an order of magnitude increase in PM10 at the regulatory monitor in Nogales, AZ (maximum increase: 12 to 474 μg m ?3). Implications:Regulatory air quality standards are based on outdoor ambient air measurements. However, a large fraction of time is typically spent indoors where a variety of activities including cooking, heating, tobacco smoking, and cleaning can lead to elevated PM concentrations. This study investigates the influence of meteorology, outdoor PM, and indoor activities on indoor air pollution (IAP) levels in the United States–Mexico border region. Results indicate that cooking fuel type and meteorology greatly influence the IAP in homes, with biomass fuel use causing the largest increase in PM concentration. 相似文献
3.
Continued development of personal air pollution monitors is rapidly improving government and research capabilities for data collection. In this study, we tested the feasibility of using GPS-enabled personal exposure monitors to collect personal exposure readings and short-term daily PM 2.5 measures at 15 fixed locations throughout a community. The goals were to determine the accuracy of fixed-location monitoring for approximating individual exposures compared to a centralized outdoor air pollution monitor, and to test the utility of two different personal monitors, the RTI MicroPEM V3.2 and TSI SidePak AM510. For personal samples, 24-hr mean PM 2.5 concentrations were 6.93 μg/m 3 (stderr = 0.15) and 8.47 μg/m 3 (stderr = 0.10) for the MicroPEM and SidePak, respectively. Based on time–activity patterns from participant journals, exposures were highest while participants were outdoors (MicroPEM = 7.61 µg/m 3, stderr = 1.08, SidePak = 11.85 µg/m 3, stderr = 0.83) or in restaurants (MicroPEM = 7.48 µg/m 3, stderr = 0.39, SidePak = 24.93 µg/m 3, stderr = 0.82), and lowest when participants were exercising indoors (MicroPEM = 4.78 µg/m 3, stderr = 0.23, SidePak = 5.63 µg/m 3, stderr = 0.08). Mean PM 2.5 at the 15 fixed locations, as measured by the SidePak, ranged from 4.71 µg/m 3 (stderr = 0.23) to 12.38 µg/m 3 (stderr = 0.45). By comparison, mean 24-h PM 2.5 measured at the centralized outdoor monitor ranged from 2.7 to 6.7 µg/m 3 during the study period. The range of average PM 2.5 exposure levels estimated for each participant using the interpolated fixed-location data was 2.83 to 19.26 µg/m 3 (mean = 8.3, stderr = 1.4). These estimated levels were compared with average exposure from personal samples. The fixed-location monitoring strategy was useful in identifying high air pollution microclimates throughout the county. For 7 of 10 subjects, the fixed-location monitoring strategy more closely approximated individuals’ 24-hr breathing zone exposures than did the centralized outdoor monitor. Highlights are: Individual PM 2.5 exposure levels vary extensively by activity, location and time of day; fixed-location sampling more closely approximated individual exposures than a centralized outdoor monitor; and small, personal exposure monitors provide added utility for individuals, researchers, and public health professionals seeking to more accurately identify air pollution microclimates. Implications: Personal air pollution monitoring technology is advancing rapidly. Currently, personal monitors are primarily used in research settings, but could they also support government networks of centralized outdoor monitors? In this study, we found differences in performance and practicality for two personal monitors in different monitoring scenarios. We also found that personal monitors used to collect outdoor area samples were effective at finding pollution microclimates, and more closely approximated actual individual exposure than a central monitor. Though more research is needed, there is strong potential that personal exposure monitors can improve existing monitoring networks. 相似文献
4.
Particulate matter is an important air pollutant, especially in closed environments like underground subway stations. In this study, a total of 13 elements were determined from PM 10 and PM 2.5 samples collected at two subway stations (Imam Khomeini and Sadeghiye) in Tehran’s subway system. Sampling was conducted in April to August 2011 to measure PM concentrations in platform and adjacent outdoor air of the stations. In the Imam Khomeini station, the average concentrations of PM 10 and PM 2.5 were 94.4?±?26.3 and 52.3?±?16.5 μg m ?3 in the platform and 81.8?±?22.2 and 35?±?17.6 μg m ?3 in the outdoor air, respectively. In the Sadeghiye station, mean concentrations of PM 10 and PM 2.5 were 87.6?±?23 and 41.3?±?20.4 μg m ?3 in the platform and 73.9?±?17.3 and 30?±?15 μg m ?3, in the outdoor air, respectively. The relative contribution of elemental components in each particle fraction were accounted for 43 % (PM 10) and 47.7 % (PM 2.5) in platform of Imam Khomeini station and 15.9 % (PM 10) and 18.5 % (PM 2.5) in the outdoor air of this station. Also, at the Sadeghiye station, each fraction accounted for 31.6 % (PM 10) and 39.8 % (PM 2.5) in platform and was 11.7 % (PM 10) and 14.3 % (PM 2.5) in the outdoor. At the Imam Khomeini station, Fe was the predominant element to represent 32.4 and 36 % of the total mass of PM 10 and PM 2.5 in the platform and 11.5 and 13.3 % in the outdoor, respectively. At the Sadeghiye station, this element represented 22.7 and 29.8 % of total mass of PM 10 and PM 2.5 in the platform and 8.7 and 10.5 % in the outdoor air, respectively. Other major crustal elements were 5.8 % (PM 10) and 5.3 % (PM 2.5) in the Imam Khomeini station platform and 2.3 and 2.4 % in the outdoor air, respectively. The proportion of other minor elements was significantly lower, actually less than 7 % in total samples, and V was the minor concentration in total mass of PM 10 and PM 2.5 in both platform stations. 相似文献
5.
Abstract The impact of outdoor and indoor pollution sources on indoor air quality in Santiago, Chile was investigated. Toward this end, 16 homes were sampled in four sessions. Each session included an outdoor site and four homes using different unvented space heaters (electric or central heating, compressed natural gas, liquefied petroleum gas, and kerosene). Average outdoor fine particulate matter (PM 2.5) concentrations were very high (55.9 μg·m -3), and a large fraction of these particles penetrated indoors. PM 2.5 and several PM 2.5 components (including sulfate, elemental carbon, organic carbon, metals, and polycyclic aromatic hydrocarbons) were elevated in homes using kerosene heaters. Nitrogen dioxide (NO 2) and ultrafine particles (UFPs) were higher in homes with combustion heaters as compared with those with electric heaters or central heating. A regression model was used to assess the effect of heater use on continuous indoor PM 2.5 concentrations when windows were closed. The model found an impact only for kerosene heaters (45.8 μg m -3). 相似文献
6.
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
7.
PM 2.5 (particulate matter with an aerodynamic diameter <2.5 μm) samples were collected in the indoor environments of 15 urban homes and their adjacent outdoor environments in Alexandria, Egypt, during the spring time. Indoor and outdoor carbon dioxide (CO 2) levels were also measured concurrently. The results showed that indoor and outdoor PM 2.5 concentrations in the 15 sites, with daily averages of 45.5 ± 11.1 and 47.3 ± 12.9 µg/m 3, respectively, were significantly higher than the ambient 24-hr PM 2.5 standard of 35 µg/m 3 recommended by the U.S. Environmental Protection Agency (EPA). The indoor PM 2.5 and CO 2 levels were correlated with the corresponding outdoor levels, demonstrating that outdoor convection and infiltration could lead to direct transportation indoors. Ventilation rates were also measured in the selected residences and ranged from 1.6 to 4.5 hr ?1 with median value of 3.3 hr ?1. The indoor/outdoor (I/O) ratios of the monitored homes varied from 0.73 to 1.65 with average value of 0.99 ± 0.26 for PM 2.5, whereas those for CO 2 ranged from 1.13 to 1.66 with average value of 1.41 ± 0.15. Indoor sources and personal activities, including smoking and cooking, were found to significantly influence indoor levels.Implications: Few studies on indoor air quality were carried out in Egypt, and the scarce data resulted from such studies do not allow accurate assessment of the current situation to take necessary preventive actions. The current research investigates indoor levels of PM2.5 and CO2 in a number of homes located in the city of Alexandria as well as the potential contribution from both indoor and outdoor sources. The study draws attention of policymakers to the importance of the establishment of national indoor air quality standards to protect human health and control air pollution in different indoor environments. 相似文献
9.
Exposure 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 PM 2.5 (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 PM 2.5 concentration (13.2 ± 13.7 µg/m 3) was similar to the average measured Grimm 11-R PM 2.5 concentration (11.3 ± 15.1 µg/m 3). The overall correlation ( r2) for PM 2.5 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/m 3) was also similar to that measured with the Grimm 11-R (4.8 ± 16.5 µg/m 3) 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 PM 2.5 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 PM 2.5. 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. 相似文献
10.
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
11.
Methylcyclopentadienyl manganese tricarbonyl (MMT) is a manganese-based gasoline additive used to enhance automobile performance. MMT has been used in Canadian gasoline for about 20 yr. Because of the potential for increased levels of Mn in particulate matter resulting from automotive exhausts, a large-scale population-based exposure study (∼1000 participant periods) was conducted in Toronto, Canada, to estimate the distribution of 3-day average personal exposures to particulate matter (PM 2.5 and PM 10) and Mn. A stratified, three-stage, two-phase probability, longitudinal sample design of the metropolitan population was employed. Residential indoor and outdoor, and ambient levels (at a fixed site and on a roof) of PM 2.5, PM 10, and Mn were also measured. Supplementary data on traffic counts, meteorology, MMT levels in gasoline, personal occupations, and activities (e.g. amount of vehicular usage) were collected. Overall precision (%RSD) for analysis of duplicate co-located samples ranged from 2.5 to 5.0% for particulate matter and 3.1 to 5.5% for Mn. The detection limits were 1.47 and 3.45 μg m -3 for the PM 10 and PM 2.5 fractions, respectively, and 5.50 and 1.83 ng m -3 for Mn in PM 10 and PM 2.5, respectively. These low detection limits permitted the reporting of concentrations for >98% of the samples. For PM 10, the personal particulate matter levels (median 48.5 μg m -3) were much higher than either indoor (23.1 μg m -3) or outdoor levels (23.6 μg m -3). The median levels for PM 2.5 for personal, indoor, and outdoor were 28.4, 15.4 and 13.2 μg m -3, respectively. The correlation between PM 2.5 personal exposures and indoor concentrations was high (0.79), while correlations between personal and the outdoor, fixed site and roof site were low (0.16–0.27). Indoor Mn concentration distributions (in PM 2.5 and PM 10), unlike particulate matter, exhibited much lower and less variable levels that the corresponding outdoor data. The median personal exposure was 8.0 ng m -3, compared with 4.7 and 8.6 ng m -3, respectively, for the indoor and outdoor distributions. The highest correlations occurred for personal vs indoor data (0.56) and for outdoor vs roof site data (0.66), and vs fixed site data (0.56). The concentration of Mn in particulate matter, expressed in ppm (w/w), revealed that the fixed site was the highest, followed by the roof site, outdoor, indoor, and personal. The personal and indoor data showed a statistically significant correlation (0.68) while all other correlations between personal or indoor data and outdoor or fixed-site data were quite small. The low correlations of personal and indoor levels with outdoor levels suggest that different sources in the indoor and outdoor microenvironments produce particle matter with dissimilar composition. The correlation results indicate that neither the roof- nor fixed-site concentrations can adequately predict personal particulate matter or Mn exposures. 相似文献
12.
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
13.
Abstract Particle infiltration is a key determinant of the indoor concentrations of ambient particles. Few studies have examined the influence of particle composition on infiltration, particularly in areas with high concentrations of volatile particles, such as ammonium nitrate (NH 4NO 3). A comprehensive indoor monitoring study was conducted in 17 Los Angeles–area homes. As part of this study, indoor/outdoor concentration ratios during overnight (nonindoor source) periods were used to estimate the fraction of ambient particles remaining airborne indoors, or the particle infiltration factor (F INF), for fine particles (PM 2.5), its nonvolatile (i.e., black carbon [BC]) and volatile (i.e., nitrate [NO 3 ?]) components, and particle sizes ranging between 0.02 and 10 μm. F INF was highest for BC (median = 0.84) and lowest for NO 3 ? (median = 0.18). The low F INF for NO 3 ? was likely because of volatilization of NO 3 ? particles once indoors, in addition to depositional losses upon building entry. The F INF for PM 2.5 (median = 0.48) fell between those for BC and NO 3 ?, reflecting the contributions of both particle components to PM 2.5. F INF varied with particle size, air-exchange rate, and outdoor NO 3 ? concentrations. The F INF for particles between 0.7 and 2 μm in size was considerably lower during periods of high as compared with low outdoor NO 3 ? concentrations, suggesting that outdoor NO 3 ? particles were of this size. This study demonstrates that infiltration of PM 2.5 varies by particle component and is lowest for volatile species, such as NH 4NO 3. Our results suggest that volatile particle components may influence the ability for outdoor PM concentrations to represent indoor and, thus, personal exposures to particles of ambient origin, because volatilization of these particles causes the composition of PM 2.5 to differ indoors and outdoors. Consequently, particle composition likely influences observed epidemiologic relationships based on outdoor PM concentrations, especially in areas with high concentrations of NH 4NO 3 and other volatile particles. 相似文献
14.
Metropolitan residents are concerned about their exposure to airborne pollutants. But establishing these exposures is challenging. A compact personal exposure kit (PEK) was developed to evaluate personal integrated exposure (PIE) from time-resolved data to particulate matter with aerodynamic diameter less than 2.5 μm (PM 2.5) in five microenvironments, including office, home, commuting, other indoor activities (other than home and office), and outdoor activities experienced both on weekdays and weekends. The study was conducted in Hong Kong. The PEK measured PM 2.5, reported location and several other factors, stored collected data, as well as reported the data back to the investigators using global system for mobile communication (GSM) telemetry. Generally, PM 2.5 concentrations in office microenvironment were found to be the smallest (13.0 μg/m 3), whereas the largest PM 2.5 concentration microenvironments were experienced during outdoor activities (54.4 μg/m 3). Participants spent more than 85% of their time indoors, including in offices, homes, and other public indoor venues. On average, 42% and 81% of the time were spent in homes, which contributed 52% and 79% of PIE (during weekdays and weekends, respectively), suggesting that improvement of air quality in homes may reduce overall exposures and indicating the need for actions to mitigate possible public health burdens in Hong Kong. This study also found that various indoor/outdoor microenvironments experienced by urban office workers cannot be accurately represented by general urban air quality data reported from the regulatory monitoring. Such personalized air quality information, especially while in transit or in offices and homes, may provide improved information on population exposures to air pollution. Implications: A newly developed personal exposure kit (PEK) was used to monitor PM2.5 exposure of metropolitan citizens in their daily life. Different microenvironments and time durations caused various personal integrated exposure (PIE). The stationary monitoring method for PIE was also compared and evaluated with PEK. Positive protection actions can be taken after understanding the major contribution to PM2.5 exposure. 相似文献
15.
Abstract Average concentrations of particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM 2.5) in Steubenville, OH, have decreased by more than 10 μg/m 3 since the landmark Harvard Six Cities Study 1 associated the city’s elevated PM 2.5 concentrations with adverse health effects in the 1980s. Given the promulgation of a new National Ambient Air Quality Standard (NAAQS) for PM 2.5 in 1997, a current assessment of PM 2.5 in the Steubenville region is warranted. The Steubenville Comprehensive Air Monitoring Program (SCAMP) was conducted from 2000 through 2002 to provide such an assessment. The program included both an outdoor ambient air monitoring component and an indoor and personal air sampling component. This paper, which is the first in a series of four that will present results from the outdoor portion of SCAMP, provides an overview of the outdoor ambient air monitoring program and addresses statistical issues, most notably autocorrelation, that have been overlooked by many PM 2.5 data analyses. The average PM 2.5 concentration measured in Steubenville during SCAMP (18.4 μg/m 3) was 3.4g/m 3 above the annual PM 2.5 NAAQS. On average, sulfate and organic material accounted for ~31% and 25%, respectively, of the total PM 2.5 mass. Local sources contributed an estimated 4.6 μg/m 3 to Steubenville’s mean PM 2.5 concentration. PM 2.5 and each of its major ionic components were significantly correlated in space across all pairs of monitoring sites in the region, suggesting the influence of meteorology and long-range transport on regional PM 2.5 concentrations. Statistically significant autocorrelation was observed among time series of PM 2.5 and component data collected at daily and 1-in-4-day frequencies during SCAMP. Results of spatial analyses that accounted for autocorrelation were generally consistent with findings from previous studies that did not consider autocorrelation; however, these analyses also indicated that failure to account for autocorrelation can lead to incorrect conclusions about statistical significance. 相似文献
16.
Outdoor levels of fine particles (PM 2.5; particles <2.5 μm) have been associated with cardiovascular health. Persons with existing cardiovascular disease have been suggested to be especially vulnerable. It is unclear, how well outdoor concentrations of PM 2.5 and its constituents measured at a central site reflect personal exposures in Southern European countries. The objective of the study was to assess the relationship between outdoor and personal concentrations of PM 2.5, absorbance and sulphur among post-myocardial infarction patients in Barcelona, Spain.Thirty-eight subjects carried personal PM 2.5 monitors for 24-h once a month (2–6 repeated measurements) between November 2003 and June 2004. PM 2.5 was measured also at a central outdoor monitoring site. Light absorbance (a proxy for elemental carbon) and sulphur content of filter samples were determined as markers of combustion originating and long-range transported PM 2.5, respectively.There were 110, 162 and 88 measurements of PM 2.5, absorbance and sulphur, respectively. Levels of outdoor PM 2.5 (median 17 μg m 3) were lower than personal PM 2.5 even after excluding days with exposure to environmental tobacco smoke (ETS) (median after exclusion 27 μg m 3). However, outdoor concentrations of absorbance and sulphur were similar to personal concentrations after exclusion of ETS. When repeated measurements were taken into account, there was a statistically significant association between personal and outdoor absorbance when adjusting for ETS (slope 0.66, p<0.001), but for PM 2.5 the association was weaker (slope 0.51, p=0.066). Adjustment for ETS had little effect on the respective association of S (slope 0.69, p<0.001).Our results suggest that outdoor measurements of absorbance and sulphur can be used to estimate both the daily variation and levels of personal exposures also in Southern European countries, especially when exposure to ETS has been taken into account. For PM 2.5, indoor sources need to be carefully considered. 相似文献
17.
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
18.
Behavioral and environmental determinants of PM 2.5 personal exposures were analyzed for 201 randomly selected adult participants (25–55 years old) of the EXPOLIS study in Helsinki, Finland. Personal exposure concentrations were higher than respective residential outdoor, residential indoor and workplace indoor concentrations for both smokers and non-smokers. Mean personal exposure concentrations of active smokers (31.0±31.4 μg m −3) were almost double those of participants exposed to environmental tobacco smoke (ETS) (16.6±11.8 μg m −3) and three times those of participants not exposed to tobacco smoke (9.9±6.2 μg m −3). Mean indoor concentrations of PM 2.5 when a member of the household smoked indoors (20.8±23.9 μg m −3) were approximately 2.5 times the concentrations of PM 2.5 when no smoking was reported (8.2±5.2 μg m −3). Interestingly, however, both mean (8.2 μg m −3) and median (6.9 μg m −3) residential indoor concentrations for non-ETS exposed participants were lower than residential outdoor concentrations (9.5 and 7.3 μg m −3, respectively). In simple linear regression models residential indoor concentrations were the best predictors of personal exposure concentrations. Correlations ( r2) between PM 2.5 personal exposure concentrations of all participants, both smoking and non-smoking, and residential indoor, workplace indoor, residential outdoor and ambient fixed site concentrations were 0.53, 0.38, 0.17 and 0.16, respectively. Predictors for personal exposure concentrations of non-ETS exposed participants identified in multiple regression were residential indoor concentrations, workplace concentrations and traffic density in the nearest street from home, which accounted for 77% of the variance. Subsequently, step-wise regression not including residential and workplace indoor concentrations as input (as these are frequently not available), identified ambient PM 2.5 concentration and home location, as predictors of personal exposure, accounting for 47% of the variance. Ambient fixed site PM 2.5 concentrations were closely related to residential outdoor concentrations ( r2=0.9, p=0.000) and PM 2.5 personal exposure concentrations were higher in summer than during other seasons. Personal exposure concentrations were significantly ( p=0.040) higher for individuals living downtown compared with individuals in suburban family homes. Further analysis will focus on comparisons of determinants between Helsinki and other EXPOLIS centers. 相似文献
19.
This study integrates the relationship between measured surface concentrations of particulate matter 10 μm or less in diameter (PM 10), satellite-derived aerosol optical depth (AOD), and meteorology in Roda, Virginia, during 2008. A multiple regression model was developed to predict the concentrations of particles 2.5 μm or less in diameter (PM 2.5) at an additional location in the Appalachia region, Bristol, TN. The model was developed by combining AOD retrievals from Moderate Resolution Imaging Spectro-radiometer (MODIS) sensor on board the EOS Terra and Aqua Satellites with the surface meteorological observations. The multiple regression model predicted PM 2.5 ( r2 = 0.62), and the two-variable (AOD-PM 2.5) model predicted PM 2.5 ( r2 = 0.4). The developed model was validated using particulate matter recordings and meteorology observations from another location in the Appalachia region, Hazard, Kentucky. The model was extrapolated to the Roda, VA, sampling site to predict PM 2.5 mass concentrations. We used 10 km x 10 km resolution MODIS 550 nm AOD to predict ground level PM 2.5. For the relevant period in 2008, in Roda, VA, the predicted PM 2.5 mass concentration is 9.11 ± 5.16 μg m -3 (mean ± 1SD). Implications: This is the first study that couples ground-based Particulate Matter measurements with satellite retrievals to predict surface air pollution at Roda, Virginia. Roda is representative of the Appalachian communities that are commonly located in narrow valleys, or “hollows,” where homes are placed directly along the roads in a region of active mountaintop mining operations. Our study suggests that proximity to heavy coal truck traffic subjects these communities to chronic exposure to coal dust and leads us to conclude that there is an urgent need for new regulations to address the primary sources of this particulate matter. 相似文献
20.
ABSTRACT We conducted a multi-pollutant exposure study in Baltimore, MD, in which 15 non-smoking older adult subjects (>64 years old) wore a multi-pollutant sampler for 12 days during the summer of 1998 and the winter of 1999. The sampler measured simultaneous 24-hr integrated personal exposures to PM 25, PM 10, SO 4 2-, O 3, NO 2, SO 2, and exhaust-related VOCs. Results of this study showed that longitudinal associations between ambient PM 2.5 concentrations and corresponding personal exposures tended to be high in the summer (median Spearman's r = 0.74) and low in the winter (median Spearman's r = 0.25). Indoor ventilation was an important determinant of personal PM 2.5 exposures and resulting personal-ambient associations. Associations between personal PM 25 exposures and corresponding ambient concentrations were strongest for well-ventilated indoor environments and decreased with ventilation. This decrease was attributed to the increasing influence of indoor PM 2 5 sources. Evidence for this was provided by SO 4 2-measurements, which can be thought of as a tracer for ambient PM 25. For SO 4 2-, personal-ambient associations were strong even in poorly ventilated indoor environments, suggesting that personal exposures to PM 2.5 of ambient origin are strongly associated with corresponding ambient concentrations. The results also indicated that the contribution of indoor PM 2.5 sources to personal PM 2.5 exposures was lowest when individuals spent the majority of their time in well-ventilated indoor environments. Results also indicate that the potential for confounding by PM 2.5 co-pollutants is limited, despite significant correlations among ambient pollutant concentrations. In contrast to ambient concentrations, PM 2.5 exposures were not significantly correlated with personal exposures to PM 2.5-10, PM 2.5 of non-ambient origin, O 3, NO 2, and SO 2. Since a confounder must be associated with the exposure of interest, these results provide evidence that the effects observed in the PM 2.5 epidemiologic studies are unlikely to be due to confounding by the PM 2.5 co-pollutants measured in this study. 相似文献
|