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1.
Shahedul A. Khan 《The International journal of environmental studies》2013,70(4):650-666
Numerous studies have demonstrated a fairly consistent association between fine particulate matter (PM2.5) and respiratory disease hospital admissions (respiratory hospitalization) in Canada. Most recently, there has been increased concern about the impacts of PM2.5 in the Canadian prairies, mainly caused by activities such as agriculture, mining, forest fires, and oil and gas production. In this study, we characterize the trend of PM2.5 concentrations in the Canadian prairies. Our trend analysis estimates the time point at which PM2.5 took an upturn from a non-increasing trend. We then quantify the association between PM2.5 and respiratory hospitalizations before and after this time point. Our analyses revealed that: (a) on average, the atmospheric concentration of PM2.5 went through a transition between 28 September 2009 and 25 February 2010 in the Canadian prairies; (b) an increasing concentration of PM2.5 was observed after completing the transition, (c) there was a significant positive association between PM2.5 and respiratory hospitalization after the time point at which PM2.5 took an upturn; and (d) the relative risk estimates for PM2.5 on respiratory hospitalization were generally higher after the time point at which PM2.5 took an upturn than before this time point. 相似文献
2.
Christos Halios Mat Santamouris Maria Kapsalaki Dimitris Tsakos 《The Science of the total environment》2009,407(17):4894-4901
The aim of the present work is to study the occupants' exposure to fine particulate concentrations in ten nightclubs (NCs) in Athens, Greece. Measurements of PM1 and PM2.5 were made in the outdoor and indoor environment of each NC. The average indoor PM1 and PM2.5 concentrations were found to be 181.77 μg m− 3 and 454.08 μg m− 3 respectively, while the corresponding outdoor values were 11.04 μg m− 3 and 32.19 μg m− 3. Ventilation and resuspension rates were estimated through consecutive numerical experiments with an indoor air quality model and were found to be remarkably lower than the minimum values recommended by national standards. The relative effects of the ventilation and smoking on the occupants' exposures were examined using multiple regression techniques. It was found that given the low ventilation rates, the effect of smoking as well as the occupancy is of the highest importance. Numerical evaluations showed that if the ventilation rates were at the minimum values set by national standards, then the indoor exposures would be reduced at the 70% of the present exposure values. 相似文献
3.
Shao L Shi Z Jones TP Li J Whittaker AG Bérubé KA 《The Science of the total environment》2006,367(1):261-272
An in vitro plasmid assay was employed to study the bioreactivity of PM (particulate matter) in Beijing air. It was found that the TD20 (toxic dose of PM causing 20% of plasmid DNA damage) of Beijing PM can be as low as 28 microg ml(-1) and as high as >1000 microg ml(-1). Comparison of the physical properties, such as morphology and size distribution, and oxidative potential indicates that the PM(2.5) (particulate matter with an aerodynamic diameter of 2.5 microm or less) has a stronger oxidative capacity than PM(10) (particulate matter with an aerodynamic diameter of 10 microm or less), and that the higher number percentages of soot aggregates and lower number percentages of mineral and fly ashes are associated with the higher oxidative capacity. Although the mass of PM(10) during dust storms is commonly 5 times higher than that during non-dust storm episodes, the oxidative capacity of PM(10)s of dust storms is much lower than that of the non-dust storm PM(10)s. The water-soluble fractions and intact whole particle solutions of Beijing airborne particles produce similar plasmid assay results, demonstrating that the bioreactivity of Beijing airborne particles is mainly sourced from the water-soluble fraction. In the samples with stronger bioreactivity, the total analyzed water soluble Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As and Pb (ppm) concentrations are higher. The water soluble zinc shows a good negative correlation with TD20s, suggesting that the water-soluble zinc is probably the major element responsible for the plasmid DNA damage. 相似文献
4.
Role of Saharan dust in the relationship between particulate matter and short-term daily mortality among the elderly in Madrid (Spain) 总被引:1,自引:0,他引:1
Background
Saharan dust outbreaks are a common phenomenon in the Madrid atmosphere. The current Directive 2008/50 CE governing air quality in European cities, draws no distinction between which particulate matter (PM10, PM2.5 or PM10-2.5) would be the best indicator on days with/without Saharan dust intrusions. This study sought to identify the role played by Saharan dust in the relationship between particulate matter (PM10, PM2.5 and PM10-2.5) concentrations and daily mortality among the elderly in the city of Madrid.Methods
We conducted an ecological longitudinal time-series study on daily mortality among the over-75 age group, from 2003 to 2005. Poisson regression models were constructed for days with and without Saharan dust intrusions. The following causes of daily mortality were analysed: total organic causes except accidents (International Classification of Diseases-10th revision (ICD-10): A00-R99); circulatory causes (ICD-10: I00-I99); and respiratory causes (ICD-10: J00-J99). Daily mean PM10, PM2.5 and PM10-2.5 levels were used as independent variables. Control variables were: other ambient pollutants (chemical, biotic and acoustic); trend; seasonalities; influenza epidemics; and autocorrelations between mortality series.Results
While daily mean PM2.5 concentrations in Madrid displayed a significant statistical association with daily mortality for all the above causes on days without Saharan dust intrusions, this association was not in evidence for PM10 or PM10-2.5 in the multivariate models. The relative risks (RRs) obtained for an increase of 10 μg/m3 in PM2.5 concentrations were: 1.023 (1.010-1.036) for total organic causes; 1.033 (1.031-1.035) for circulatory causes; and 1.032 (1.004-1.059) for respiratory causes. On Saharan dust days, a significant statistical association was detected between PM10 (though not PM2.5 or PM10-2.5) and mortality for all 3 causes analysed, with RRs statistically similar to those reported for PM2.5.Conclusions
The best air quality indicators for evaluating the short-term health effects of particulate matter in Madrid are therefore PM10 concentrations on days with, and PM2.5 concentrations on days without Saharan dust outbreaks. This fact should be taken into account in a European Directive regulating ambient air quality in almost all countries in the Mediterranean area. 相似文献5.
This study numerically investigates airflow characteristics and particulate matter (PM) transport in multi-room buildings for different natural ventilation patterns with the same air change rate. Four typical natural ventilation patterns (full-open, pass-through, right short-circuit and left short-circuit), representing the ratios of the outlet-to-inlet opening size ranging from 1.67 to 0.17, are considered to study multi-room airflow characteristics. A measured indoor PM10 profile in Taipei Metropolis is input into the above four ventilation patterns as the initial condition of the PM size distribution. The time variation of indoor PM10/PM2.5/PM1 concentrations in each room for various ventilation patterns is next investigated. The effect of ventilation pattern on particle removal mechanism is emphasized. The results show that although the air change rate of the building is the same, airflow characteristics and PM transport behaviors are quite different for various ventilation patterns. The removal efficiencies of PM10 for the four ventilation patterns are all found to be much better than those of PM2.5 and PM1. Particle escape is the major mechanism to remove PM for rooms with double-sided ventilation, whereas particle deposition is important for single-sided ventilation rooms. 相似文献
6.
Short-term effect of fine particulate matter (PM2.5) on daily mortality due to diseases of the circulatory system in Madrid (Spain) 总被引:2,自引:0,他引:2
Introduction
Owing to their small size, fine particles, i.e., those having a diameter ≤ 2.5 μm (PM2.5), have a high alveolar penetration capacity, thereby triggering a local inflammatory process with circulatory repercussion. Despite being linked to respiratory and cardiovascular morbidities, there is limited evidence of an association between this type of particulate matter and short-term increases in mortality.Objective
The aim of this study was to analyse and quantify the short-term impact of PM2.5 on daily mortality due to diseases of the circulatory system, registered in Madrid from 1 January 2003 to 31 December 2005.Methods
An ecological longitudinal time-series study was conducted, with risks being quantified by means of Poisson regression models. As a dependent variable, we took daily mortality registered in Madrid from 1 January 2003 to 31 December 2005, attributed to all diseases of the circulatory system as classified under heads I00-I99 of the International Classification of Diseases-10th revision (ICD-10) and broken down as follows: I21, acute myocardial infarction (AMI); I20, I22-I25, other ischemic heart diseases; and I60-I69, cerebrovascular diseases. The independent variable was daily mean PM2.5 concentration. The other variables controlled for were: chemical pollution (PM10, O3, SO2, NO2 and NOx); acoustic and biotic pollution; influenza; minimum and maximum temperatures; seasonalities; trend; and autocorrelation of the series.Results
A linear relationship was observed between PM2.5 levels and mortality due to diseases of the circulatory system. For every increase of 10 μg/m3 in daily mean PM2.5 concentration, the relative risks (RR) were as follows: for overall circulatory mortality, associations were established at lags 2 and 6, with RR of 1.022 (1.005-1.039) and 1.025 (1.007-1.043) respectively; and for AMI mortality, there was an association at lag 6, with an RR of 1.066 (1.032-1.100). The corresponding attributable risks percent (AR%) were 2.16%, 2.47% and 6.21% respectively. No statistically significant association was found with other ischemic heart diseases or with cerebrovascular diseases.Conclusion
PM2.5 concentrations are an important risk factor for daily circulatory-cause mortality in Madrid. From a public health point of view, the planning and implementation of specific measures targeted at reducing these levels constitute a pressing need. 相似文献7.
This comprehensive study, a first in Flanders, Belgium, aimed at characterizing the residential indoor air quality of subgroups that took part in the European Community Respiratory Health Survey (ECRHS I—1991 and ECHRS II—1996) questionnaire-based asthma and related illnesses studies. This pilot study aimed at the evaluation of particulate matter and various inorganic gaseous compounds in residences in Antwerp. In addition personal exposure to the gaseous compounds of one individual per residence was assessed. The main objective was to obtain some base-line pollutant levels and compare these with studies performed in other cities, to estimate the indoor air quality in residences in Antwerp. Correlations between the various pollutant levels, indoor:outdoor ratios and the micro-environments of each residence were investigated. This paper presents results on indoor and ambient PM1, PM2.5 and PM10 mass concentrations, its elemental composition in terms of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Pb, Al, Si, S and Cl and the water-soluble ionic concentrations in terms of SO42−, NO32−, Cl−, NH4+ K+, Ca2+. In addition, indoor, ambient and personal exposure levels of the gases NO2, SO2, and O3 were determined. Elevated indoor:outdoor ratios were found for NO2 in residences containing gas stoves. In smoker's houses increased PM concentrations of 58 and 43% were found for the fine and coarse fractions respectively. Contrary to the fact that all I/O ratios of the registered elements in each individual house were significantly correlated to each other, no correlation could be established between the I/O ratios of the different houses, thus indicating a unique micro-environment for each residence. Linear relationships between the particulate matter elemental composition, SO2 and O3 levels indoors and outdoors could be established. No linear relationships between indoor and outdoor NO2 and particulate mass concentrations were found. 相似文献
8.
Ma Y Chen R Pan G Xu X Song W Chen B Kan H 《The Science of the total environment》2011,409(13):2473-2477
Fine particulate matter (PM2.5) is not a criteria pollutant in China, and few studies were conducted in the country to investigate the health impact of PM2.5. In this study, we did a time-stratified case-crossover analysis to examine the association between PM2.5 and daily mortality in Shenyang, an industrial center in northeast China. Daily mortality, air pollution and weather data from August 1, 2006 to December 31, 2008 in Shenyang were collected. A time-stratified case-crossover approach was used to estimate the association of PM2.5 with both total and cause-specific mortality. Controls were selected as matched days of the week in the same month. Potential effect modifiers, such as age, gender, and season, were also examined. We found significant associations between PM2.5 and daily mortality in Shenyang. A 10 μg/m3 increment in the 2-day moving average (lag 01) concentrations of PM2.5 corresponded to 0.49% (95% CI: 0.19%, 0.79%), 0.53% (95% CI: 0.09%, 0.97%), and 0.97% (95% CI: 0.01%, 1.94%) increase of total, cardiovascular, and respiratory mortality, respectively. The associations appeared to be stronger in older people (aged ≥ 75 years), in females and during the warm season. To our knowledge, this is the longest PM2.5 health study in time duration in China. Our findings provide new information on the adverse health effects of PM2.5, and may have implications for environmental policy making and standard setting in China. 相似文献
9.
Louie PK Chow JC Chen LW Watson JG Leung G Sin DW 《The Science of the total environment》2005,338(3):267-281
Chemically speciated PM2.5 measurements were made at roadside, urban, and rural background sites in Hong Kong for 1 year during 2000/2001 to determine the spatial and temporal variations of PM2.5 mass and chemical composition in this highly populated region. Annual average PM2.5 concentrations at the urban and rural sites were 34.1 and 23.7 microg m(-3), respectively, approximately 50-100% higher than the United States' annual average National Ambient Air Quality Standard (NAAQS) of 15 microg m(-3). Daily PM2.5 concentrations exceeded the U.S. 24-h NAAQS of 65 microg m(-3) on 19 days, reaching 131+/-8 microg m(-3) at the roadside site on 02/28/2001. Carbonaceous aerosol is the largest contributor to PM2.5 mass (explaining 52-75% of PM2.5 mass at the two urban sites and 32% at the background site), followed by ammonium sulfate (ranging from 23% to 37% at the two urban sites and 51% at the background site). Ammonium sulfate and crustal concentrations showed more uniform spatial distributions, while the largest urban-rural contrasts found in carbonaceous aerosol (likely due to emissions from on-road gasoline and diesel vehicles). Marine influences accounted for 7% of the mass at the background site (more than twice as much as at the two urban sites). Ternary diagrams are utilized to illustrate the different spatial patterns. 相似文献
10.
Hopke PK Cohen DD Begum BA Biswas SK Ni B Pandit GG Santoso M Chung YS Rahman SA Hamzah MS Davy P Markwitz A Waheed S Siddique N Santos FL Pabroa PC Seneviratne MC Wimolwattanapun W Bunprapob S Vuong TB Duy Hien P Markowicz A 《The Science of the total environment》2008,404(1):103-112
Over the past decade, member states of the Regional Co-operation Agreement (RCA), an intergovernmental agreement for the East Asia and Pacific region under the auspices of the IAEA with the assistance of international organizations and financial institutions such as the World Bank and the Asian Development Bank, have started to set in place policies and legislation for air pollution abatement. To support planning and evaluate the effectiveness of control programs, data are needed that characterizes urban air quality. The focus of this measurement program describe in this report is on size segregated particulate air pollution. Such airborne particulate matter can have a significant impact on human health and urban visibility. These data provide the input to receptor models that may permit the mitigation of these impacts by identification and quantitative apportionment of the particle sources. The aim of this report is to provide an overview of the measurements of concentrations and composition of particulate air pollution in two size fractions across the participating countries. For many of the large cities in this region, the measured particulate matter concentrations are greater than air quality standards or guidelines that have been adopted in developed countries. 相似文献
11.
Sources and properties of non-exhaust particulate matter from road traffic: a review 总被引:11,自引:0,他引:11
While emissions control regulation has led to a substantial reduction in exhaust emissions from road traffic, currently non-exhaust emissions from road vehicles are unabated. These include particles from brake wear, tyre wear, road surface abrasion and resuspension in the wake of passing traffic. Quantification of the magnitude of such emissions is problematic both in the laboratory and the field and the latter depends heavily upon a knowledge of the physical and chemical properties of non-exhaust particles. This review looks at each source in turn, reviewing the available information on the source materials and particles derived from them in laboratory studies. In a final section, some of the key publications dealing with measurements in road tunnels and the roadside environment are reviewed. It is concluded that with the exception of brake dust particles which may be identified from their copper (Cu) and antimony (Sb) content, unequivocal identification of particles from other sources is likely to prove extremely difficult, either because of the lack of suitable tracer elements or compounds, or because of the interactions between sources prior to the emission process. Even in the case of brake dust, problems will arise in distinguishing directly emitted particles from those arising from resuspension of deposited brake dust from the road surface, or that derived from entrainment of polluted roadside soils, either directly or as a component of road surface dust. 相似文献
12.
Factors influencing relationships between personal and ambient concentrations of gaseous and particulate pollutants 总被引:1,自引:0,他引:1
Kathleen Ward Brown Jeremy A. Sarnat Brent A. Coull 《The Science of the total environment》2009,407(12):3754-3765
Previous exposure studies have shown considerable inter-subject variability in personal-ambient associations. This paper investigates exposure factors that may be responsible for inter-subject variability in these personal-ambient associations. The personal and ambient data used in this paper were collected as part of a personal exposure study conducted in Boston, MA, during 1999-2000. This study was one of a group of personal exposure panel studies funded by the U.S. Environmental Protection Agency's National Exposure Research Laboratory to address areas of exposure assessment warranting further study, particularly associations between personal exposures and ambient concentrations of particulate matter and gaseous co-pollutants. Twenty-four-hour integrated personal, home indoor, home outdoor and ambient sulfate, elemental carbon (EC), PM2.5, ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide were measured simultaneously each day. Fifteen homes in the Boston area were measured for 7 days during winter and summer. A previous paper explored the associations between personal-indoor, personal-outdoor, personal-ambient, indoor-outdoor, indoor-ambient and outdoor-ambient PM2.5, sulfate and EC concentrations. For the current paper, factors that may affect personal exposures were investigated, while controlling for ambient concentrations. The data were analyzed using mixed effects regression models. Overall personal-ambient associations were strong for sulfate during winter (p < 0.0001) and summer (p < 0.0001) and PM2.5 during summer (p < 0.0001). The personal-ambient mixed model slope for PM2.5 during winter but was not significant at p = 0.10. Personal exposures to most pollutants, with the exception of NO2, increased with ventilation and time spent outdoors. An opposite pattern was found for NO2 likely due to gas stoves. Personal exposures to PM2.5 and to traffic-related pollutants, EC and NO2, were higher for those individuals living close to a major road. Both personal and indoor sulfate and PM2.5 concentrations were higher for homes using humidifiers. The impact of outdoor sources on personal and indoor concentrations increased with ventilation, whereas an opposite effect was observed for the impact of indoor sources. 相似文献
13.
Three monthly 24-hour samples of airborne aerosols (PM10 and PM2.5) were collected at an urban and a rural site of the North central, semi-arid part of India during May 2006 to March 2008. Seven trace metals (Pb, Zn, Ni, Fe, Mn, Cr and Cu) were determined for both sizes. The annual mean concentration for PM10 was 154.2 µg/m3 and 148.4 µg/m3 at urban and rural sites whereas PM2.5 mean concentration was 104.9 µg/m3 and 91.1 µg/m3 at urban and rural sites, respectively. Concentrations of PM10 and PM2.5 have been compared with prescribed WHO standards and NAAQS given by CPCB India and were found to be higher. Weekday/weekend variations of PM10 and PM2.5 have been studied at both monitoring sites. Lower particulate pollutant levels were found during weekends, which suggested that anthropogenic activities are major contributor of higher ambient particulate concentration during weekdays. Significant seasonal variations of particulate pollutants were obtained using the daily average concentration of PM10 and PM2.5 during the study period. PM2.5/PM10 ratios at urban and rural sites were also determined during the study period, which also showed variation between the seasons. Three factors have been identified using Principal Component Analysis at the sampling sites comprising resuspension of road dust due to vehicular activities, solid waste incineration, and industrial emission at urban site whereas resuspension of soil dust due to vehicular emission, construction activities and wind blown dust carrying industrial emission, were common sources at rural site. 相似文献
14.
Asian dust storms (ADS) originating from the arid deserts of Mongolia and China are a well-known springtime meteorological phenomenon throughout East Asia. The ventilation systems in office utilize air from outside and therefore it is necessary to understand how these dust storms affect the concentrations of PM2.5 and PM10 in both the indoor and outdoor air. We measured dust storm pollution particles in an office building using a direct-reading instrument (PC-2 Quartz Crystal Microbalance, QCM) that measured particle size and concentration every 10 min for 1 h, three times a day. A three-fold increase in the concentrations of PM2.5 and PM10 in the indoor and outdoor air was recorded during the dust storms. After adjusting for other covariates, autoregression models indicated that PM2.5 and PM10 in the indoor air increased significantly (21.7 μg/m3 and 23.0 μg/m3 respectively) during dust storms. The ventilation systems in high-rise buildings utilize air from outside and therefore the indoor concentrations of fine and coarse particles in the air inside the buildings are significantly affected by outside air pollutants, especially during dust storms. 相似文献
15.
Performance evaluation of air quality models for predicting PM10 and PM2.5 concentrations at urban traffic intersection during winter period 总被引:1,自引:0,他引:1
There are several models that can be used to evaluate roadside air quality. The comparison of the operational performance of different models pertinent to local conditions is desirable so that the model that performs best can be identified. Three air quality models, namely the 'modified General Finite Line Source Model' (M-GFLSM) of particulates, the 'California Line Source' (CALINE3) model, and the 'California Line Source for Queuing & Hot Spot Calculations' (CAL3QHC) model have been identified for evaluating the air quality at one of the busiest traffic intersections in the city of Guwahati. These models have been evaluated statistically with the vehicle-derived airborne particulate mass emissions in two sizes, i.e. PM10 and PM2.5, the prevailing meteorology and the temporal distribution of the measured daily average PM10 and PM2.5 concentrations in wintertime. The study has shown that the CAL3QHC model would make better predictions compared to other models for varied meteorology and traffic conditions. The detailed study reveals that the agreements between the measured and the modeled PM10 and PM2.5 concentrations have been reasonably good for CALINE3 and CAL3QHC models. Further detailed analysis shows that the CAL3QHC model performed well compared to the CALINE3. The monthly performance measures have also led to the similar results. These two models have also outperformed for a class of wind speed velocities except for low winds (<1 m s(-1)), for which, the M-GFLSM model has shown the tendency of better performance for PM10. Nevertheless, the CAL3QHC model has outperformed for both the particulate sizes and for all the wind classes, which therefore can be optional for air quality assessment at urban traffic intersections. 相似文献
16.
H. Wise D. Balharry L.J. Reynolds K. Sexton R.J. Richards 《The Science of the total environment》2006,360(1-3):60
There is strong epidemiological evidence of association between PM10 (particulate matter with an aerodynamic diameter less than or equal to 10 μm) and adverse health outcomes including death and increased hospital admissions for cardiopulmonary conditions. Ambient PM10 surrogates such as diesel exhaust particles (DEP), a common component of UK PM10, have been shown to induce lung inflammation in both humans and rodents. To date, few studies have reported on the toxicological response of UK PM10 in experimental animals.This study examines the pulmonary toxicological responses in male Sprague Dawley rats following the intratracheal instillation of Cardiff urban PM10. A mild but significant change in lung permeability was observed in the lung post-instillation of a high (10 mg) dose of the whole PM10 as adjudged by increases in lung to body weight ratio and total acellular lavage protein. Such effects were less marked following instillation of a water-soluble fraction (80% of the total mass) but histological examination showed that lung capillaries were swollen in size with this treatment.In conclusion, conventional toxicological, histological and toxicogenomic studies have indicated that Cardiff PM10 exhibits low bioreactivity in the form of mild permeability changes. Differential gene expression was observed when the lung was treated with whole PM10, containing durable particles, in comparison with the water-soluble fraction of PM10 that was devoid of particles. Such changes were linked to different histopathological events within the lung. 相似文献
17.
Atmospheric particulate matter (PM) fractions (PM(10) and PM(2.5)) were sampled concurrently between June 2004 and May 2005 at two sites (urban and suburban) in Izmir, Turkey. The elemental composition of PM (Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn) was determined using inductively coupled plasma-optical emission spectrometer. Elemental compositions of several PM sources were also characterized. Positive matrix factorization (PMF) and chemical mass balance modeling (CMB) were applied to determine the PM sources and their contributions to air concentrations. The major contributors to PM were fossil fuel burning, traffic emissions, mineral industries and marine salt according to the PMF results. However, undetermined parts were more than 40%. On the other hand, the contributions to PM could be determined completely by CMB, and the dominant contributor was traffic with >70% at the two sites. Fossil fuel burning, mineral industries, marine salt and natural gas-fired power plant were the minor contributors. 相似文献
18.
The multi-criteria decision making methods, Preference Ranking Organization METHods for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA), and the two-way Positive Matrix Factorization (PMF) receptor model were applied to airborne fine particle compositional data collected at three sites in Hong Kong during two monitoring campaigns held from November 2000 to October 2001 and November 2004 to October 2005. PROMETHEE/GAIA indicated that the three sites were worse during the later monitoring campaign, and that the order of the air quality at the sites during each campaign was: rural site > urban site > roadside site. The PMF analysis on the other hand, identified 6 common sources at all of the sites (diesel vehicle, fresh sea salt, secondary sulphate, soil, aged sea salt and oil combustion) which accounted for approximately 68.8 ± 8.7% of the fine particle mass at the sites. In addition, road dust, gasoline vehicle, biomass burning, secondary nitrate, and metal processing were identified at some of the sites. Secondary sulphate was found to be the highest contributor to the fine particle mass at the rural and urban sites with vehicle emission as a high contributor to the roadside site. The PMF results are broadly similar to those obtained in a previous analysis by PCA/APCS. However, the PMF analysis resolved more factors at each site than the PCA/APCS. In addition, the study demonstrated that combined results from multi-criteria decision making analysis and receptor modelling can provide more detailed information that can be used to formulate the scientific basis for mitigating air pollution in the region. 相似文献
19.
Pérez N Pey J Castillo S Viana M Alastuey A Querol X 《The Science of the total environment》2008,407(1):527-540
Results on interpretation of the variability of regional background PM levels in the Western Mediterranean basin (WMB) are presented. Mean PM levels recorded at Montseny, MSY (North-Eastern Spain) in the 2002-2007 period reached 17, 13 and 11 µg/m3 of PM10, PM2.5 and PM1, respectively.The daily evolution of PM levels is regulated by the breeze circulation (mountain and sea breezes). PM levels are lower at the rural sites at night owing to the nocturnal drainage flows and to the lowering of the mixing layer height below the MSY high. These nocturnal low levels allowed us to estimate the continental background PM levels. At midday, the atmospheric pollutants accumulated in the pre-coastal depression are transported upwards by the breeze, increasing PM levels.Maximum PM10 levels were recorded in summer, and February-March and November, and minimum values in the rest of the year coinciding with the highest frequency of Atlantic advection. PM peak episodes attributed to Saharan dust outbreaks were recorded in summer and February-March. In addition, anticyclonic situations (February-March and November) may impact in elevated rural areas by increasing hourly levels of PM1 up to 75 µg/m3. This scenario induces the stagnation of pollutants in the pre-coastal depression. Solar radiation activates mountain winds, transporting polluted air masses from the valleys to elevated areas resulting in an increase of fine PM levels in areas outside the boundary layer.A significant decrease in PM annual means (40% and 34% for the entire monitoring period, 7 µgPM10/m3 and 5 µgPM2.5/m3) was recorded at MSY between 2002 and 2007. There appears to be no single cause behind these trends. This could partially be ascribed to the varying frequency and intensity of Saharan dust episodes, but also to large-scale meteorological processes or cycles, and/or to local or meso-scale processes such as nearby anthropogenic emission sources. 相似文献
20.
The inorganic main elements, trace elements and PAHs were determined from selected PM1, PM2.5 and PM10 samples collected at the Nordic background station in Virolahti during different seasons and during the wildfire episodes in 2006. Submicron particles are those most harmful to human beings, as they are able to penetrate deep into the human respiratory system and may cause severe health effects. About 70-80%, of the toxic trace elements, like lead, cadmium, arsenic and nickel, as well as PAH compounds, were found in particles smaller than 1 µm. Furthermore, the main part of the copper, zinc, and vanadium was associated with submicron particles. In practice, all the PAHs found in PM10 were actually in PM2.5. For PAHs and trace elements, it is more beneficial to analyse the PM2.5 or even the PM1 fraction instead of PM10, because exclusion of the large particles reduces the need for sample cleaning to minimize the matrix effects during the analysis. During the wildfire episodes, the concentrations of particles smaller than 2.5 µm, as well as those of submicron particles, increased, and also the ratio PM1/PM10 increased to about 50%. On the fire days, the mean potassium concentration was higher in all particle fractions, but ammonium and nitrate concentrations rose only in particles smaller than 1.0 µm. PAH concentrations rose even to the same level as in winter. 相似文献