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1.
Dhaka, the capital of Bangladesh, is among the most polluted cities in the world. This research evaluates seasonal patterns, day-of-week patterns, spatial gradients, and trends in PM 2.5 (<2.5 µm in aerodynamic diameter), PM 10 (<10 µm in aerodynamic diameter), and gaseous pollutants concentrations (SO 2, NO 2, CO, and O 3) monitored in Dhaka from 2013 to 2017. It expands on past work by considering multiple monitoring sites and air pollutants. Except for ozone, the average concentrations of these pollutants showed strong seasonal variation, with maximum during winter and minimum during monsoon, with the pollution concentration of PM 2.5 and PM 10 being roughly five- to sixfold higher during winter versus monsoon. Our comparisons of the pollutant concentrations with Bangladesh NAAQS and U.S. NAAQS limits analysis indicate particulate matter (PM 2.5 and PM 10) as the air pollutants of greatest concern, as they frequently exceeded the Bangladesh NAAQS and U.S. NAAQS, especially during nonmonsoon time. In contrast, gaseous pollutants reported far fewer exceedances throughout the study period. During the study period, the highest number of exceedances of NAAQS limits in Dhaka City (Darus-Salam site) were found for PM 2.5 (72% of total study days), followed by PM 10 (40% of total study days), O 3 (1.7% of total study days), SO 2 (0.38% of total study days), and CO (0.25% of total study days). The trend analyses results showed statistically significant positive slopes over time for SO 2 (5.6 ppb yr ?1, 95% confidence interval [CI]: 0.7, 10.5) and CO (0.32 ppm yr ?1, 95% CI: 0.01, 0.56), which suggest increase in brick kilns operation and high-sulfur diesel use. Though statistically nonsignificant annual decreasing slopes for PM 2.5 (?4.6 µg/m 3 yr ?1, 95% CI: ?12.7, 3.6) and PM 10 (?2.7 µg/m 3 yr ?1, 95% CI: ?7.9, 2.5) were observed during this study period, the PM 2.5 concentration is still too high (~ 82.0 µg/m 3) and can cause severe impact on human health. Implications: This study revealed key insights into air quality challenges across Dhaka, Bangladesh, indicating particulate matter (PM) as Dhaka’s most serious air pollutant threat to human health. The results of these analyses indicate that there is a need for immediate further investigations, and action based on those investigations, including the conduct local epidemiological PM exposure-human health effects studies for this city, in order to determine the most public health effective interventions. 相似文献
2.
Atmospheric particulate matter (PM) is hypothesized to increase the risk of myocardial infarction (MI). However, the epidemiological evidence is inconsistent. We identified 33 studies with more than 4 million MI patients and applied meta-analysis and meta-regression to assess the available evidence. Twenty-five studies presented the effects of the PM level on hospitalization for MI patients, while eight studies showed the effects on mortality. An increase in PM 10 was associated with hospitalization and mortality in myocardial infarction patients (RR per 10 μg/m 3?=?1.011, 95 % CI 1.006–1.016; RR per 10 μg/m 3?=?1.008, 95 % CI 1.004–1.012, respectively); PM 2.5 also increased the risk of hospitalization and mortality in MI patients (RR per 10 μg/m 3?=?1.024, 95 % CI 1.007–1.041 for hospitalization and RR per 10 μg/m 3?=?1.012, 95 % CI 1.010–1.015 for mortality). The results of the cumulative meta-analysis indicated that PM 10 and PM 2.5 were associated with myocardial infarctionwith the addition of new studies each year. In conclusion, short-term exposure to high PM 10 and PM 2.5 levels revealed to increase risk of hospitalization and mortality for myocardial infarction. Policy support of pollution control and individual protection was strongly recommended. 相似文献
3.
Abstract Air samples of particulate matter (PM) with an aerodynamic diameter less than 10 µm (PM 10) were collected from six sites in Bangkok, Thailand, using high-volume air samplers. Daily samples were taken at intervals of 12 days from November 1999 to November 2000. Size-selected sampling using a multislit Andersen size-fractionated cascade impactor was undertaken at one site in central Bangkok to identify particulate size distribution. The annual average PM 10 concentration at all six sites exceeded the Thailand National Ambient Air Quality Standard (NAAQS) of 50 µg/m 3. The daily PM 10 concentrations at heavy traffic roadside areas ranged between 30 and 160 µg/m 3. The highest PM 10 level occurred during the winter period (November–February), which is the dry season. From our results, which are based on a 1-yr survey, it can be observed that the particulate concentrations are associated with traffic volumes and seasonal factors (temperature and rainfall). The relative importance of size fractions in contributing to PM load is presented and discussed. Twenty polycyclic aromatic hydro-carbons (PAHs) associated with PM have been identified and quantified. The summed PAHs based on the 20 species had an average concentration of 60 ng/m 3. Benzo(e)pyrene, indeno(123cd)pyrene, and benzo(ghi)perylene were the major compounds with average concentrations of 8, 10, and 13 ng/m 3, respectively. Results indicate that more than 97% of PAHs were found in the small particulate size range of <0.95 µm. 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 Particles emitted from gravel processing sites are one contributor to worsening air quality in Taiwan. Major pollution sources at gravel processing sites include gravel and sand piles, unpaved roads, material crushers, and bare ground. This study analyzed fugitive dust emission characteristics at each pollution source using several types of particle samplers, including total suspended particulates (TSP), suspended particulate (PM 10), fine suspended particulate (PM 2.5), particulate sizer, and dust-fall collectors. Furthermore, silt content and moisture in the gravel were measured to develop particulate emission factors. The results showed that TSP (<100 µm) concentrations at the boundary of gravel sites ranged from 280 to 1290 µg/m 3, which clearly exceeds the Taiwan hourly air quality standard of 500 µg/m 3. Moreover, PM 10 concentrations, ranging from 135 to 550 µg/m 3, were also above the daily air quality standard of 125 µg/m 3 and approximately 1.2 and 1.5 times the PM 2.5 concentrations, ranging from 105 to 470 µg/m 3. The size distribution analysis reveals that mass mean diameter and geometric standard deviation ranged from 3.2 to 5.7 µm and from 2.82 to 5.51, respectively. In this study, spraying surfactant was the most effective control strategy to abate windblown dust from unpaved roads, having a control efficiency of approximately 93%, which is significantly higher than using paved road strategies with a control efficiency of approximately 45%. For paved roads, wet suppression provided the best dust control efficiencies ranging from 50 to 83%. Re-vegetation of disturbed ground had dust control efficiencies ranging from 48 to 64%. 相似文献
6.
An indoor/outdoor monitoring programme of PM 10 was carried out in two sports venues (a fronton and a gymnasium). Levels always below 50 μg m ?3 were obtained in the fronton and outdoor air. Due to the climbing chalk and the constant process of resuspension, concentrations above 150 μg m ?3 were registered in the gymnasium. The chalk dust contributed to CO 3 2? concentrations of 32?±?9.4 μg m ?3 in this sports facility, which represented, on average, 18 % of the PM 10 mass. Here, the carbonate levels were 128 times higher than those registered outdoors. Much lower concentrations, around 1 μg m ?3, were measured in the fronton. The chalk dust is also responsible for the high Mg 2+ concentrations in the gym (4.7?±?0.89 μg m ?3), unfolding a PM 10 mass fraction of 2.7 %. Total carbon accounted for almost 30 % of PM 10 in both indoor spaces. Aerosol size distributions were bimodal and revealed a clear dependence on physical activities and characteristics of the sports facilities. The use of climbing chalk in the gymnasium contributed significantly to the coarse mode. The average geometric mean diameter, geometric standard deviation and total number of coarse particles were 0.77 μm, 2.79 cm ?3 and 28 cm ?3, respectively. 相似文献
7.
Abstract In response to community concerns, the air quality impact of imploding a 22-story building in east Baltimore, MD, was studied. Time- and space-resolved concentrations of indoor and outdoor particulate matter (PM) (nominally 0.5–10 µm) were measured using a portable nephelometer at seven and four locations, respectively. PM 10 levels varied in time and space; there was no measurable effect observed upwind of the implosion. The downwind peak PM 10 levels varied with distance (54,000–589 µg/m 3) exceeding pre-implosion levels for sites 100 and 1130 m 3000- and 20-fold, respectively. Estimated outdoor 24-hr integrated mass concentrations varied from 15 to 72 µg/m 3. The implosion did not result in the U.S. Environmental Protection Agency (EPA) National Ambient Air Quality Standard (NAAQS) for PM 10 being exceeded. X-ray fluorescence analysis indicated that the elemental composition was dominated by crustal elements: calcium (57%), silicon (23%), aluminum (7.6%), and iron (6.1%). Lead was above background but at a low level (0.17 µg/m 3). Peak PM 10 concentrations were short-lived; most sites returned to background within 15 min. No increase in indoor PM 10 was observed even at the most proximate 250 m location. These results demonstrate that a building implosion can have a severe but short-lived impact on community air quality. Effective protection is offered by being indoors or upwind. 相似文献
8.
A gas chromatography–mass spectrometry method has been proposed for the determination of low-level mutagenic and carcinogenic nitrosamines in particulate matter. The method includes the collection of particulate matters (PM 2.5 and PM 10) using a dichotomous Partisol 2025 sampler and extraction of the compounds from aqueous solution with dichloromethane/2-propanol after sonication with a slightly basic water solution prior to their GC-MS analysis in electron impact mode. The obtained recoveries of nitrosamines ranged from 92.4 to 99.2 %, and the precision of this method, as indicated by the relative standard deviations, was within the range of 0.95–2.46?%. The detection limits obtained from calculations using the GC-MS results based on S/N?=?3 were found within the range from 4 to 22 pg/m 3. The predominant nitrosamines determined in particulate matter were N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodibutylamine and N-nitrosomorpholine. Furthermore, N-mono- and dinitrosopiperazine and N-nitrosoethylbutylamine were also determined. N-dinitrosopiperazine was detected in PM 2.5 samples at the highest concentrations of up to 22.85 ng/m 3 and in PM 2.5–10 samples at concentrations up to 7.60 ng/m 3 in winter, whereas it was found in PM 2.5 samples up to 5.15 ng/m 3 and in PM 2.5–10 samples up to 3.12 ng/m 3 in summer. The total concentrations of nitrosamines were up to 161.4 ng/m 3 in fine and 53.90 ng/m 3 in coarse fractions in winter, whereas in summer were up to 35.24 and 12.60 ng/m 3, respectively. The concentration levels of nitrosamines fluctuated significantly within a year, with higher means and peak concentrations in the winter compared to that in the summertime. The seasonal variations of particle-associated nitrosamine concentrations were investigated together with their relationships with meteorological parameters using Pearson’s correlation analysis in the winter and summer periods. Analysis of variance was used to determine which concentrations of nitrosamines were statistically different from one another and, together with meteorological parameters and discriminant analysis, was used to classify the particle samples by particle size according to seasons. The classification results of the particle samples in different seasons were very satisfactory, allowing 99.5 % of cases to be correctly grouped. 相似文献
9.
Purpose The concentrations of PM 10 mass, PM 2.5 mass and particle number were continuously measured for 18 months in urban background locations across Europe to determine the spatial and temporal variability of particulate matter. Methods Daily PM 10 and PM 2.5 samples were continuously collected from October 2002 to April 2004 in background areas in Helsinki, Athens, Amsterdam and Birmingham. Particle mass was determined using analytical microbalances with precision of 1 ??g. Pre- and post-reflectance measurements were taken using smoke-stain reflectometers. One-minute measurements of particle number were obtained using condensation particle counters. Results The 18-month mean PM 10 and PM 2.5 mass concentrations ranged from 15.4 ??g/m 3 in Helsinki to 56.7 ??g/m 3 in Athens and from 9.0 ??g/m 3 in Helsinki to 25.0 ??g/m 3 in Athens, respectively. Particle number concentrations ranged from 10,091 part/cm 3 in Helsinki to 24,180 part/cm 3 in Athens with highest levels being measured in winter. Fine particles accounted for more than 60% of PM 10 with the exception of Athens where PM 2.5 comprised 43% of PM 10. Higher PM mass and number concentrations were measured in winter as compared to summer in all urban areas at a significance level p?0.05. Conclusions Significant quantitative and qualitative differences for particle mass across the four urban areas in Europe were observed. These were due to strong local and regional characteristics of particulate pollution sources which contribute to the heterogeneity of health responses. In addition, these findings also bear on the ability of different countries to comply with existing directives and the effectiveness of mitigation policies. 相似文献
10.
Abstract Many studies have shown strong associations between particulate matter (PM) levels and a variety of health outcomes, leading to changes in air quality standards in many regions, especially the United States and Europe. Kuwait, a desert country located on the Persian Gulf, has a large petroleum industry with associated industrial and urban land uses. It was marked by environmental destruction from the 1990 Iraqi invasion and subsequent oil fires. A detailed particle characterization study was conducted over 12 months in 2004–2005 at three sites simultaneously with an additional 6 months at one of the sites. Two sites were in urban areas (central and southern) and one in a remote desert location (northern). This paper reports the concentrations of particles less than 10 µm in diameter (PM 10) and fine PM (PM 2.5), as well as fine particle nitrate, sulfate, elemental carbon (EC), organic carbon (OC), and elements measured at the three sites. Mean annual concentrations for PM 10 ranged from 66 to 93 µg/m 3 across the three sites, exceeding the World Health Organization (WHO) air quality guidelines for PM 10 of 20 µg/m 3. The arithmetic mean PM 2.5 concentrations varied from 38 and 37 µg/m 3 at the central and southern sites, respectively, to 31 µg/m 3 at the northern site. All sites had mean PM 2.5 concentrations more than double the U.S. National Ambient Air Quality Standard (NAAQS) for PM 2.5. Coarse particles comprised 50–60% of PM 10. The high levels of PM 10 and large fraction of coarse particles comprising PM 10 are partially explained by the resuspension of dust and soil from the desert crust. However, EC, OC, and most of the elements were significantly higher at the urbanized sites, compared with the more remote northern site, indicating significant pollutant contributions from local mobile and stationary sources. The particulate levels in this study are high enough to generate substantial health impacts and present opportunities for improving public health by reducing airborne PM. 相似文献
11.
Abstract This paper analyzes the air quality impacts of coal-fired power plants in the northern passageway of the West-East Power Transmission Project in China. A three-layer Lagrangian model called ATMOS, was used to simulate the spatial distribution of incremental sulfur dioxide (SO 2) and coarse particulate matter (PM 10) concentrations under different emission control scenarios. In the year 2005, the emissions from planned power plants mainly affected the air quality of Shanxi, Shaanxi, the common boundary of Inner Mongolia and Shanxi, and the area around the boundary between Inner Mongolia and Ningxia. In these areas, the annually averaged incremental SO 2 and PM 10 concentrations exceed 2 and 2.5 µg/m3, respectively. The maximum increases of the annually averaged SO 2 and PM 10 concentrations are 8.3 and 7.2 µg/m 3, respectively, which occur around Hancheng city, near the boundary of the Shaanxi and Shanxi provinces. After integrated control measures are considered, the maximum increases of annually averaged SO 2 and PM 10 concentrations fall to 4.9 and 4 µg/m 3, respectively. In the year 2010, the areas affected by planned power plants are mainly North Shaanxi, North Ningxia, and Northwest Shanxi. The maximum increases of the annually averaged SO 2 and PM 10 concentrations are, respectively, 6.3 and 5.6 µg/m 3, occurring in Northwest Shanxi, which decline to 4.4 and 4.1 µg/m 3 after the control measures are implemented. The results showed that the proposed power plants mainly affect the air quality of the region where the power plants are built, with little impact on East China where the electricity will be used. The influences of planned power plants on air quality will be decreased greatly by implementing integrated control measures. 相似文献
12.
ABSTRACT Positive Matrix Factorization analysis of PM 2.5 chemical speciation data collected from 2015–2017 at Washington State Department of Ecology’s urban NCore (Beacon Hill) and near-road (10th and Weller) sites found similar PM 2.5 sources at both sites. Identified factors were associated with gasoline exhaust, diesel exhaust, aged and fresh sea salt, crustal, nitrate-rich, sulfur-rich, unidentified urban, zinc-rich, residual fuel oil, and wood smoke. Factors associated with vehicle emissions were the highest contributing sources at both sites. Gasoline exhaust emissions comprised 26% and 21% of identified sources at Beacon Hill and 10th and Weller, respectively. Diesel exhaust emissions comprised 29% of identified sources at 10th and Weller but only 3% of identified sources at Beacon Hill. Correlation of the diesel exhaust factor with measured concentrations of black carbon and nitrogen oxides at 10th and Weller suggests a method to predict PM 2.5 from diesel exhaust without a full chemical speciation analysis. While most PM 2.5 sources exhibit minimal change over time, primary PM 2.5 from gasoline emissions is increasing on average 0.18 µg m ?3 per year in Seattle. 相似文献
13.
Arsenic is a toxic element that affects human health and is widely distributed in the environment. In the area of study, the main Spanish and second largest European industrial ceramic cluster, the main source of arsenic aerosol is related to the impurities in some boracic minerals used in the ceramic process. Epidemiological studies on cancer occurrence in Spain points out the study region as one with the greater risk of cancer. Concentrations of particulate matter and arsenic content in PM 10 and PM 2.5 were measured and characterized by ICP-MS in the area of study during the years 2005–2010. Concentrations of PM 10 and its arsenic content range from 27 to 46 μg/m 3 and from 0.7 to 6 ng/m 3 in the industrial area, respectively, and from 25 to 40 μg/m 3 and from 0.7 to 2.8 ng/m 3 in the urban area, respectively. Concentrations of PM 2.5 and its arsenic content range from 12 to 14 μg/m 3 and from 0.5 to 1.4 ng/m 3 in the urban background area, respectively. Most of the arsenic content is present in the fine fraction, with ratios of PM 2.5/PM 10 in the range of 0.65–0.87. PM 10, PM 2.5, and its arsenic content show a sharp decrease in recent years associated with the economic downturn, which severely hit the production of ceramic materials in the area under study. The sharp production decrease due to the economic crisis combined with several technological improvements in recent years such as substitution of boron, which contains As impurities as raw material, have reduced the concentrations of PM 10, PM 2.5, and As in air to an extent that currently meets the existing European regulations. 相似文献
14.
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
15.
Considering tobacco smoke as one of the most health-relevant indoor sources, the aim of this work was to further understand its negative impacts on human health. The specific objectives of this work were to evaluate the levels of particulate-bound PAHs in smoking and non-smoking homes and to assess the risks associated with inhalation exposure to these compounds. The developed work concerned the application of the toxicity equivalency factors approach (including the estimation of the lifetime lung cancer risks, WHO) and the methodology established by USEPA (considering three different age categories) to 18 PAHs detected in inhalable (PM 10) and fine (PM 2.5) particles at two homes. The total concentrations of 18 PAHs (Σ PAHs) was 17.1 and 16.6 ng m ?3 in PM 10 and PM 2.5 at smoking home and 7.60 and 7.16 ng m ?3 in PM 10 and PM 2.5 at non-smoking one. Compounds with five and six rings composed the majority of the particulate PAHs content (i.e., 73 and 78 % of Σ PAHs at the smoking and non-smoking home, respectively). Target carcinogenic risks exceeded USEPA health-based guideline at smoking home for 2 different age categories. Estimated values of lifetime lung cancer risks largely exceeded (68–200 times) the health-based guideline levels at both homes thus demonstrating that long-term exposure to PAHs at the respective levels would eventually cause risk of developing cancer. The high determined values of cancer risks in the absence of smoking were probably caused by contribution of PAHs from outdoor sources. 相似文献
16.
Recent epidemiological and toxicological studies have shown associations between particulate matter and human health. However, the estimates of adverse health effects are inconsistent across many countries and areas. The stratification and interaction models were employed within the context of the generalized additive Poisson regression equation to examine the acute effects of fine particles on respiratory health and to explore the possible joint modification of temperature, humidity, and season in Beijing, China, for the period 2004–2009. The results revealed that the respiratory health damage threshold of the PM 2.5 concentration was mainly within the range of 20–60 μg/m 3, and the adverse effect of excessively high PM 2.5 concentration maintained a stable level. In the most serious case, an increase of 10 μg/m 3 PM 2.5 results in an elevation of 4.60 % (95 % CI 3.84–4.60 %) and 4.48 % (95 % CI 3.53–5.41 %) with a lag of 3 days, values far higher than the average level of 0.69 % (95 % CI 0.54–0.85 %) and 1.32 % (95 % CI 1.02–1.61 %) for respiratory mortality and morbidity, respectively. There were strong seasonal patterns of adverse effects with the seasonal variation of temperature and humidity. The growth rates of respiratory mortality and morbidity were highest in winter. And, they increased 1.4 and 1.8 times in winter, greater than in the full year as PM 2.5 increased 10 μg/m 3. 相似文献
17.
In the present study, personal exposure to fine particulate matter (particulate matter with an aerodynamic diameter <2.5 μm [PM 2.5]) concentrations in an urban hotspot (central business district [CBD]) was investigated. The PM monitoring campaigns were carried out at an urban hotspot from June to October 2015. The personal exposure monitoring was performed during three different time periods, i.e., morning (8 a.m.?9 a.m.), afternoon (12.30 p.m.–1.30 p.m.), and evening (4 p.m.–5 p.m.), to cover both the peak and lean hour activities of the CBD. The median PM 2.5 concentrations were 38.1, 34.9, and 40.4 µg/m 3 during the morning, afternoon, and evening hours on the weekends. During weekdays, the median PM 2.5 concentrations were 59.5, 29.6, and 36.6 µg/m 3 in the morning, afternoon, and evening hours, respectively. It was observed that the combined effect of traffic emissions, complex land use, and micrometeorological conditions created localized air pollution hotspots. Furthermore, the total PM 2.5 lung dose levels for an exposure duration of 1 hr were 8.7 ± 5.7 and 12.3 ± 5.2 µg at CBD during weekends and weekdays, respectively, as compared with 2.5 ± 0.8 µg at the urban background (UB). This study emphasizes the need for mobile measurement for short-term personal exposure assessment complementing the fixed air quality monitoring. Implications: Personal exposure monitoring at an urban hotspot indicated space and time variation in PM concentrations that is not captured by the fixed air quality monitoring networks. The short-term exposure to higher concentrations can have a significant impact on health that need to be considered for the health risk–based air quality management. The study emphasizes the need of hotspot-based monitoring complementing the already existing fixed air quality monitoring in urban areas. The personal exposure patterns at hotspots can provide additional insight into sustainable urban planning. 相似文献
18.
Quantitative information on the contribution of dust storms to atmospheric PM 10 (particulate matter with an aerodynamic diameter ≤10 µm) levels is still lacking, especially in urban environments with close proximity to dust sources. The main objective of this study was to quantify the contribution of dust storms to PM 10 concentrations in a desert urban center, the city of Beer-Sheva, Negev, Israel, during the period of 2001–2012. Toward this end, a background value based on the “dust-free” season was used as a threshold value to identify potentially “dust days.” Subsequently, the net contribution of dust storms to PM 10 was assessed. During the study period, daily PM 10 concentrations ranged from 6 to over 2000 µg/m 3. In each year, over 10% of the daily concentrations exceeded the calculated threshold (BV t) of 71 µg/m 3. An average daily net contribution of dust to PM 10 of 122 µg/m 3 was calculated for the entire study period based on this background value. Furthermore, a dust storm intensity parameter ( Ai) was used to analyze several storms with very high PM 10 contributions (hourly averages of 1000–5197 μg/m 3). This analysis revealed that the strongest storms occurred mainly in the last 3 yr of the study. Finally, these findings indicate that this arid urban environment experiences high PM 10 levels whose origin lies in both local and regional dust events. Implications:The findings indicate that over time, the urban arid environment experiences high PM10 levels whose origin lies in local and regional dust events. It was noticed that the strongest storms have occurred mainly in the last 3 yr. It is believed that environmental changes such as global warming and desertification may lead to an increased air pollution and risk exposure to human health. 相似文献
19.
PM 2.5 and PM 2.5–10 aerosol samples were collected in four seasons during November 2010, January, April, and August 2011 at 13 urban/suburban sites and one background site in Western Taiwan Straits Region (WTSR), which is the coastal area with rapid urbanization, high population density, and deteriorating air quality. The 10 days average PM 2.5 concentrations were 92.92, 51.96, 74.48, and 89.69 μg/m 3 in spring, summer, autumn, and winter, respectively, exceeding the Chinese ambient air quality standard for annual average value of PM 2.5 (grade II, 35 μg/m 3). Temporal distribution of water-soluble inorganic ions (WSIIs) in PM 2.5 was coincident with PM 2.5 mass concentrations, showing highest in spring, lowest in summer, and middle in autumn and winter. WSIIs took considerable proportion (42.2~50.1 %) in PM 2.5 and PM 2.5–10. Generally, urban/suburban sites had obviously suffered severer pollution of fine particles compared with the background site. The WSIIs concentrations and characteristics were closely related to the local anthropogenic activities and natural environment, urban sites in cities with higher urbanization level, or sites with weaker diffuse condition suffered severer WSIIs pollution. Fossil fuel combustion, traffic emissions, crustal/soil dust, municipal constructions, and sea salt and biomass burnings were the major potential sources of WSIIs in PM 2.5 in WTSR according to the result of principal component analysis. 相似文献
20.
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
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