南宁市大气颗粒物TSP、PM10、PM2.5污染水平研究

2002年在南宁市的5个典型城市功能区内,共采集了125个大气样品(按季节分别采集),初步调查了大气中颗粒物TSP、PM10、PM2.5的污染状况。结果表明,南宁市TSP、PM10、PM2.5的污染很严重,超标率分别为67．5％、82．5％、92．5％,对人体健康危害更大的PM2．5占到了PM10的63．5％左右。重污染区PM2.5的浓度超过轻污染区近一倍。     

Fine (PM2.5), coarse (PM2.5-10), and metallic elements of suspended particulates for incense burning at Tzu Yun Yen temple in central Taiwan

Ambient suspended particulate concentrations were measured at Tzu Yun Yen temple (120 degrees, 34('), 10(") E; 24 degrees, 16('), 12(") N) in this study. This is representative of incense burning and semi-open sampling sites. The Universal-sampler collected fine and coarse particle material was used to measure suspended particulate concentrations, and sampling periods were from 16/08/2001 to 2/1/2002 at Tzu Yun Yen temple. In addition, metallic element concentrations, compositions of PM(2.5) and PM(2.5-10) for incense burning at Tzu Yun Yen temple were also analyzed in this study. The PM(2.5)/PM(10) ratios ranged between 31% and 87% and averaged 70+/-11% during incense the burning period, respectively. The median metallic element concentration order for these elements is Fe>Zn>Cr>Cd>Pb>Mn>Ni>Cu in fine particles (PM(2.5)) at the Tzu Yun Yen temple sampling site. The median metallic element concentration order for these elements is Fe>Zn>Cr>Pb>Cd>Ni>Mn>Cu in coarse particle (PM(2.5-10)) at the Tzu Yun Yen temple sampling site. Fine particulates (PM(2.5)) are the main portion of PM(10) at Tzu Yun Yen temple in this study. From the point of view of PM(10), these data reflect that the elements Fe, Zn, and Cr were the major elements distributed at Tzu Yun Yen temple in this study.     

Characteristic study of particulates and metallic elements at an urban sampling site in Taichung, central Taiwan

Atmospheric total suspended particulate concentrations and metallic element concentrations were measured at three locations, characteristic of urban, suburban and rural sites. The sampling period was from July 2000 to August 2000. The results indicated that the urban sampling site had the highest total suspended particulate concentrations (average 108.61μ1m3), followed by the suburban site (average 60.11μ1m3) and the rural site (average 53.31μ1m3). The average PM_2.5 concentrations (24.11μ1m3) were higher than the PM_2.5-10 concentrations (12.81μ1m3) at the urban site. The average distributed ratios for PM_2.5/PM_2.5-10 were about 1.29, 1.53, 0.12, 1.12 and 2.31 for Pb, Zn, Fe, Ni and Cr, respectively. The average total suspended particulate mass ratios for daytime and nighttime were about 1.72. As for the elements Cu, Pb, Zn, Fe, Ni and Cr, these ratios were about 0.63, 0.97, 0.54, 1.66, 0.53 and 1.12, respectively. The total suspended particulate daytime concentrations of Pb and Zn were positively correlated (R = 0.925) at the urban sampling site. The elements Ni and Cr were positively correlated both during the daytime (R = 0.648) and the nighttime (R = 0.511), revealing that they came from the same emission source during daytime and nighttime, at the urban sampling site.     

Particulate matter in California: part 1--Intercomparison of several PM2.5, PM10-2.5, and PM10 monitoring networks

It will be many years before the recently deployed network of fine particulate matter with an aerodynamic diameter less than 2.5 microm (PM2.5) Federal Reference Method (FRM) samplers produces information on nonattainment areas, trends, and source impacts. However, data on PM2.5 and its major constituents have been routinely collected in California for the past 20 years. The California Air Resources Board operated as many as 20 dichotomous (dichot) samplers for PM2.5 and coarse PM (PM10-2.5). The California Acid Deposition Monitoring Program (CADMP) collected 12-h-average PM2.5 and PM10 from 1988 to 1995 at ten urban and rural sites and 24-h-average PM2.5 at five urban sites since 1995. Beginning in 1994, the Children's Health Study collected 2-week averages of PM2.5 in 12 communities in southern California using the Two-Week Sampler (TWS). Comparisons of collocated samples establish relationships between the dichot, CADMP, and TWS samplers and the 82-site network of PM2.5 FRM samplers deployed since 1999 in California. PM mass data from the different monitoring programs have modest to high correlation to FRM mass data, fairly small systematic biases and negative proportional biases ranging from 7 to 22%. If the biases are taken into account, all of the programs should be considered comparable with the FRM program. Thus, historical data can be used to develop long-term PM trends in California.     

Particulate matter in California: part 2--Spatial, temporal, and compositional patterns of PM2.5, PM10-2.5, and PM10

Geographic and temporal variations in the concentration and composition of particulate matter (PM) provide important insights into particle sources, atmospheric processes that influence particle formation, and PM management strategies. In the nonurban areas of California, annual-average PM2.5 and PM10 concentrations range from 3 to 10 microg/m3 and from 5 to 18 microg/m3, respectively. In the urban areas of California, annual-averages for PM2.5 range from 7 to 30 microg/m3, with observed 24-hr peaks reaching levels as high as 160 microg/m3. Within each air basin, exceedances are a mixture of isolated events as well as periods of elevated PM2.5 concentrations that are more prolonged and regional in nature. PM2.5 concentrations are generally highest during the winter months. The exception is the South Coast Air Basin, where fairly high values occur throughout the year. Annual-average PM2.5 mass, as well as the concentrations of major components, declined from 1988 to 2000. The declines are especially pronounced for the sulfate (SO4(2-)) and nitrate (NO3-) components of PM2.5 and PM10) and correlate with reductions in ambient levels of oxides of sulfur (SOx) and oxides of nitrogen (NOx). Annual averages for PM10-2.5 and PM10 exhibited similar downwind trends from 1994 to 1999, with a slightly less pronounced decrease in the coarse fraction.     

Analysis of PM2.5and PM10 in the Atmosphere of Mexico City during 2000-2002

Abstract

During the last 10 years, high atmospheric concentrations of airborne particles recorded in the Mexico City metropolitan area have caused concern because of their potential harmful effects on human health. Four monitoring campaigns have been carried out in the Mexico City metropolitan area during 2000-2002 at three sites: (1) Xalos-toc, located in an industrial region; (2) La Merced, located in a commercial area; and (3) Pedregal, located in a residential area. Results of gravimetric and chemical analyses of 330 samples of particulate matter (PM) with an aerodynamic diameter less than 2.5 μm (PM_2.5) and PM with an aerodynamic diameter less than 10 μm (PM₁₀) indicate that (1) PM_2.5/PM₁₀ average ratios were 0.42, 0.46, and 0.52 for Xalostoc, La Merced, and Pedregal, respectively; (2) the highest PM_2.5 and PM₁₀ concentrations were found at the industrial site; (3) PM_2.5 and PM₁₀ concentrations were lower at nighttime; (4) PM_2.5 and PM₁₀ spatial averages concentrations were 35 and 76 μg/m³, respectively; and (5) when the PM_2.5 standard was exceeded, nitrate, sulfate, ammonium, organic carbon, and elemental carbon concentrations were high. Twenty-four hour averaged PM_2.5 concentrations in Mexico City and Sao Paulo were similar to those recorded in the 1980s in Los Angeles. PM₁₀ concentrations were comparable in Sao Paulo and Mexico City but 3-fold lower than those found in Santiago.     

Analysis of PM2.5 and PM10 in the atmosphere of Mexico City during 2000-2002

During the last 10 years, high atmospheric concentrations of airborne particles recorded in the Mexico City metropolitan area have caused concern because of their potential harmful effects on human health. Four monitoring campaigns have been carried out in the Mexico City metropolitan area during 2000-2002 at three sites: (1) Xalostoc, located in an industrial region; (2) La Merced, located in a commercial area; and (3) Pedregal, located in a residential area. Results of gravimetric and chemical analyses of 330 samples of particulate matter (PM) with an aerodynamic diameter less than 2.5 microm (PM2.5) and PM with an aerodynamic diameter less than 10 microm (PM10) indicate that (1) PM2.5/PM10 average ratios were 0.42, 0.46, and 0.52 for Xalostoc, La Merced, and Pedregal, respectively; (2) the highest PM2.5 and PM10 concentrations were found at the industrial site; (3) PM2.5 and PM10 concentrations were lower at nighttime; (4) PM2.5 and PM10 spatial averages concentrations were 35 and 76 microg/m3, respectively; and (5) when the PM2.5 standard was exceeded, nitrate, sulfate, ammonium, organic carbon, and elemental carbon concentrations were high. Twenty-four hour averaged PM2.5 concentrations in Mexico City and Sao Paulo were similar to those recorded in the 1980s in Los Angeles. PM10 concentrations were comparable in Sao Paulo and Mexico City but 3-fold lower than those found in Santiago.     

Comparisons of ambient air particulates concentrations (TSP,PM2.5) and dry depositions during smog and non-smog periods at Luliao,Shalu District sampling site

The concentrations of ambient total suspended particulates (TSP) and PM_2.5, and the dry depositions at a sample site at Luliao Junior High School (Luliao) in central Taiwan were measured during smog and non-smog days between December 2017 and July 2018. The results are compared to those obtained during non-smog periods in the years 2015–2017. The mean TSP and PM_2.5 concentrations and dry deposition flux were 72.41?±?26.40, 41.88?±?23.51?μg/m³, and 797.57?±?731.46?μg/m² min, respectively, on the smog days. The mean TSP and PM_2.5 concentrations and dry deposition flux on the non-smog days were 56.39?±?18.08, 34.81?±?12.59?μg/m³ and 468.93?±?600.57?μg/m² min, respectively. The mean TSP concentration in the smog period was 28% greater than that in the non-smog period, and the mean PM_2.5 concentration was 20% higher. The mean dry deposition flux in the smog period was 70% higher than that in the non-smog period at Luliao. The PM_2.5 concentrations exceeded the standards set by the Taiwan EPA (35?μg/m³ daily, and 15?μg/m³ annually). Therefore, the TSP and PM_2.5 concentrations and dry deposition must be reduced in central Taiwan on smog days. In addition, atmospheric TSP and PM_2.5 concentrations at various sampling sites were compared, and those herein were not higher than those measured in other countries. Finally, apart from the local traffic emissions, during smog periods, the other pollution source originated from the transportation process of traffic pollutants emitted in the northwest side of Taiwan.     

Elemental characterization of PM10, PM2.5 and PM1 in the town of Genoa (Italy)

The particulate matter (PM) concentration and composition, the PM10, PM2.5, PM1 fractions, were studied in the urban area of Genoa, a coastal town in the northwest of Italy. Two instruments, the continuous monitor TEOM and the sequential sampler PARTISOL, were operated almost continuously on the same site from July 2001 to September 2004. Samples collected by PARTISOL were weighted to obtain PM concentration and then analysed by PIXE (particle induced X-ray emission) and by ED-XRF (energy dispersion X-ray fluorescence), obtaining concentrations for elements from Na to Pb. Some of the filters used in the TEOM microbalance were analysed by ED-XRF to calculate Pb concentration values averaged over 7-30 d periods.     

Factors affecting the concentrations of PM10 in central Taiwan

In this study, the synoptic weather types that have high probability and low probability of producing PM10 episode are referred to as HPE and LPE, respectively. Multiple linear regressions analysis showed that NO2 was the most important contributor (35.61%) to the concentrations of PM10 for HPE weather. For LPE weather, the season factor had the greatest contribution (48.11%) to the concentrations of PM10. Using the correlation coefficients between the concentrations of PM10 and SO2 or NO2 on HPE and LPE to calculate the increase of PM10 from LPE to HPE, we found that the increase of PM10 owing to the increase of SO2 and NO2 from LPE to HPE was 12.93microg/m3 which was about 51% of the total amount of PM10 increased from LPE to HPE. Results of factor analysis showed that the first component could be attributed to the result of local pollution especially for the weather patterns of types P3 and P6, while the secondary component for the weather patterns of types P1 and P4 can be attributed to the long-range transport of SO2 pollutants from China.     

Estimating the emission source reduction of PM10 in central Taiwan

Three theoretical parent frequency distributions; lognormal, Weibull and gamma were used to fit the complete set of PM10 data in central Taiwan. The gamma distribution is the best one to represent the performance of high PM10 concentrations. However, the parent distribution sometimes diverges in predicting the high PM10 concentrations. Therefore, two predicting methods, Method I: two-parameter exponential distribution and Method II: asymptotic distribution of extreme value, were used to fit the high PM10 concentration distributions more correctly. The results fitted by the two-parameter exponential distribution are better matched with the actual high PM10 data than that by the parent distributions. Both of the predicting methods can successfully predict the return period and exceedances over a critical concentration in the future year. Moreover, the estimated emission source reductions of PM10 required to meet the air quality standard by Method I and Method II are very close. The estimated emission source reductions of PM10 range from 34% to 48% in central Taiwan.     

Analysis of PM10, PM2.5, and PM2 5-10 concentrations in Santiago, Chile, from 1989 to 2001

Daily particle samples were collected in Santiago, Chile, at four urban locations from January 1, 1989, through December 31, 2001. Both fine PM with da < 2.5 microm (PM2.5) and coarse PM with 2.5 < da < 10 microm (PM2.5-10) were collected using dichotomous samplers. The inhalable particle fraction, PM10, was determined as the sum of fine and coarse concentrations. Wind speed, temperature and relative humidity (RH) were also measured continuously. Average concentrations of PM2.5 for the 1989-2001 period ranged from 38.5 microg/m3 to 53 microg/m3. For PM2.5-10 levels ranged from 35.8-48.2 microg/m3 and for PM10 results were 74.4-101.2 microg/m3 across the four sites. Both annual and daily PM2.5 and PM10 concentration levels exceeded the U.S. National Ambient Air Quality Standards and the European Union concentration limits. Mean PM2.5 levels during the cold season (April through September) were more than twice as high as those observed in the warm season (October through March); whereas coarse particle levels were similar in both seasons. PM concentration trends were investigated using regression models, controlling for site, weekday, month, wind speed, temperature, and RH. Results showed that PM2.5 concentrations decreased substantially, 52% over the 12-year period (1989-2000), whereas PM2.5-10 concentrations increased by approximately 50% in the first 5 years and then decreased by a similar percentage over the following 7 years. These decreases were evident even after controlling for significant climatic effects. These results suggest that the pollution reduction programs developed and implemented by the Comisión Nacional del Medio Ambiente (CONAMA) have been effective in reducing particle levels in the Santiago Metropolitan region. However, particle levels remain high and it is thus imperative that efforts to improve air quality continue.     

Source identification of nickel in TSP and PM2.5 in Tokyo,Japan

This study investigates the source identification of nickel in the aerosol of the Tokyo metropolitan area. TSP and PM_2.5 samples were collected daily from August to November 2004. The samples were examined by means of the water-extraction method, followed by elemental analysis and SEM/EDX analysis. We distinguished two types of atmospheric nickel sources in the studied area: (1) particles derived from heavy oil combustion, distributed mostly in fine particles such as PM_2.5, relatively water-soluble, and containing vanadium and (2) particles derived from mechanical abrasion/erosion of metallic surfaces, distributed in coarse particles such as TSP, relatively water-insoluble, and containing chromium.     

Source apportionment of visual impairment during the California regional PM10/PM2.5 air quality study

Gases and particulate matter predictions from the UCD/CIT air quality model were used in a visibility model to predict source contributions to visual impairment in the San Joaquin Valley (SJV), the southern portion of California's Central Valley, during December 2000 and January 2001. Within the SJV, daytime (0800–1700 PST) light extinction was dominated by scattering associated with airborne particles. Measured daytime particle scattering coefficients were compared to predicted values at approximately 40 locations across the SJV after correction for the increased temperature and decreased relative humidity produced by “smart heaters” placed upstream of nephelometers. Mean fractional bias and mean fractional error were ?0.22 and 0.65, respectively, indicating reasonable agreement between model predictions and measurements. Particulate water, nitrate, organic matter, and ammonium were the major particulate species contributing to light scattering in the SJV. Daytime light extinction in the SJV averaged between December 25, 2000 and January 7, 2001 was mainly associated with animal ammonia sources (28%), diesel engines (18%), catalyst gasoline engines (9%), other anthropogenic sources (9%), and wood smoke (7%) with initial and boundary conditions accounting for 13%. The source apportionment results from this study apply to wintertime conditions when airborne particulate matter concentrations are typically at their annual maximum. Further study would be required to quantify source contributions to light extinction in other seasons.     

PM2.5–10, PM2.5 and associated water-soluble inorganic species at a coastal urban site in the metropolitan region of Rio de Janeiro

The concentrations of PM_2.5−10, PM_2.5 and associated water-soluble inorganic species (WSIS) were determined in a coastal site of the metropolitan region of Rio de Janeiro, Southeastern Brazil, from October 1998 to September 1999 (n=50). Samples were dissolved in water and analyzed for major inorganic ions. The mean (± standard deviation; median) concentrations of PM_2.5−10 and PM_2.5 were, respectively, 26 (± 16; 21) μg m⁻³ and 17 (± 13; 14) μg m⁻³. Their mean concentrations were 1.7–1.8 times higher in dry season (May–October) than in rainy season (November–April). The WSIS comprised, respectively, 34% and 28% of the PM_2.5−10 and PM_2.5 masses. Chloride, Na⁺ and Mg²⁺ were the predominant ions in PM_2.5−10, indicating a significant influence of sea-salt aerosols. In PM_2.5, SO₄²⁻ (∼97% nss-SO₄²⁻) and NH₄⁺ were the most abundant ions and their equivalent concentration ratio (SO₄²⁻/NH₄⁺ ∼1.0) suggests that they were present as (NH₄)₂SO₄ particles. The mean concentration of (NH₄)₂SO₄ was 3.4 μg m⁻³. The mean equivalent PM_2.5 NO₃⁻ concentration was eight times smaller than those of SO₄²⁻ and NH₄⁺. The PM_2.5 NO₃⁻ concentration in dry season was three times higher than in rainy season, probably due to reaction of NaCl (sea salt) with HNO₃ as a result of higher levels of NO_y during the dry season and/or reduced volatilization of NH₄NO₃ due to lower wintertime temperature. Chloride depletion was observed in both size ranges, although more pronouncely in PM_2.5.     

石河子市春季大气颗粒物TSP和PM10中微生物群落特征

近来,有研究指出颗粒物中携带导致人类过敏、呼吸系统疾病或其他类疾病的微生物,其对公众健康的影响因为研究较少而一直被低估。采用16S rDNA、18S rDNA测序方法对石河子市2015年春季TSP和PM10污染物中细菌、真菌的群落结构特征进行研究。结果表明：在门的水平上,变形菌门（Proteobacteria）和放线菌门（Actinobacteria）是石河子市春季TSP和PM10中细菌的主要菌群,子囊菌门（Ascomycota）和担子菌门（Basidiomycota）是真菌的主要菌群。在属水平上,马赛菌属（Massilia）和不动杆菌属（Acinetobacter）在16S rDNA测序结果分析中相对含量较多,格孢腔菌属（Pleospora）和Penidiella在18S rDNA测序结果分析中相对丰度较高,仍然发现了一些可能导致人类及植物患病的菌属,期望此研究结果为人类生活提供参考。     

Statistical characterization of atmospheric PM10 and PM2.5 concentrations at a non-impacted suburban site of Istanbul, Turkey

Inhalable particulate matter (PM10) has been monitored at several stations by Istanbul Municipality. On the other hand, information about fine fraction aerosols (PM2.5) in Istanbul atmosphere was not reported. In this study, 86 daily aerosol samples were collected between July 2002 and July 2003. The PM10 annual arithmetic mean value of 47.1 microg m(-3), was lower than the Turkish air quality standard of 60 microg m(-3). On the other hand, this value was found higher than the annual European Union air quality PM(10) standard of 40 microg m(-3). Furthermore, the annual mean concentration of PM2.5 20.8 microg m(-3) was found higher than The United States EPA standard of 15 microg m(-3). The statistics and relationships of fine, coarse, and inhalable particles were studied. Cyclic behavior of the monthly average concentrations of PM10 and PM2.5 data were investigated. Several frequency distribution functions were used to fit the measured data. According to Chi-squared and Kolmogorov-Smirnov tests, the frequency distributions of PM2.5 and PM10 data were found to fit Log-logistic functions.     

Characterisation of PM10 and PM2.5 particulate matter in the ambient air of Milan (Italy)

24-h simultaneous samplings of PM10 and PM2.5 particulate matter (PM) have been carried out during the period December 1997–September 1998 in the central urban area of Milan. The mass concentrations of the two fractions showed significant daily variations linked to different thermodynamic conditions of the planetary boundary layer (PBL) and characterised by higher values during wintertime. The elemental composition, determined by energy dispersive X-ray fluorescence technique, was quite different in the two fractions: in the finer one the presence of elements with crustal origin is reduced while the anthropogenic elements, with a relevant environmental and health impact, appear to be enriched. The composition data allowed a quantification of two major components of the atmospheric particulate: sulphates (mainly of secondary origin) and particles with crustal origin. An important but unmeasured component is likely constituted by organic and elemental carbon compounds.The multivariate analysis of elements, gaseous pollutants and mass concentration data-sets leads to the identification of four main sources contributing to PM10 and PM2.5 composition: vehicles exhaust emissions, resuspended crustal dust, secondary sulphates and industrial emissions. The existence of a possible background component with non-local origin is also suggested.     

Metallic characteristics of PM2.5 and PM2.5-10 for clustered Aeolian Dust Episodes occurred in an extensive fluvial basin during rainy season

Aeolian dust episodes (ADEs) have been an emergency disaster in the Kaoping River Valley during the rainy season (May-September), which can severely deteriorate ambient particulate air quality in the region surrounding the Kaoping River. Thus, this study aims to characterize the metallic fingerprint of Aeolian dust (AD) and investigate the effects of ADEs on ambient particulate air quality along the Kaoping River Valley. Four manual sampling sites adjacent to the riverside were selected to collect fine (PM2.5) and coarse (PM2.5–10) aerosol samples during and after the ADEs in the periods of six events. A total of 13 metallic elements were analyzed using an inductively coupled plasma-atomic emission spectrometer. With metallic elements analysis and nonparametric statistical methods of Wilcoxon rank-sum test and Kruskal-Wallis test, this study successfully derived the metallic indicators of ADEs. The mass ratios of crustal elements (Fe, Ca, or Al) to reference element (Cd) obtained during the ADEs were much higher than those obtained after the ADEs. High mass ratios of Fe/Cd, Ca/Cd, and Al/Cd in PM2.5-10 were observed on the influenced areas of ADEs. Among them, (Fe/Cd)2.5-10 was proven as the best indicator which can be applied to effectively validate the existence of ADEs and evaluate their influences on ambient air quality. Moreover, PM2.5 concentrations during the ADEs were 3-3.6 fold higher than those after the ADEs. PM2.5 should be a contributor to AD, even though the mass ratios of PM2.5/PM10 ranged from 0.05 to 0.20 during the ADEs. Our findings provide valuable information regarding the characteristics of the AD during the ADEs in the Kaoping River.

Implications: Indicators of (Fe/Cd)_2.5-10 are approximately applied to observe the effects of ADEs. Local governments could realize the mechanisms of S- and NW-type aeolian dust episodes (ADEs). They can cause deterioration in different ways for the regional air quality surrounding Kaoping River Valley. Residents who have been living in the influenced areas can take precautions to prevent damage from aeolian dust. Strategies for curbing ADEs must reduce the area of bare lands by artificial measures in the long period of the sunny days during the rainy season. Future research should examine physical conditions of topsoils and other chemical composition in aeolian dust.     

Source apportionment of PM2.5 and PM10 aerosols in Brisbane (Australia) by receptor modelling

Aerosol samples for PM_2.5 and PM₁₀ (particulate matter with aerodynamic diameters less than 2.5 and 10 μm, respectively) were collected from 1993 to 1995 at five sites in Brisbane, a subtropical coastal city in Australia. This paper investigates the contributions of emission sources to PM_2.5 and PM₁₀ aerosol mass in Brisbane. Source apportionment results derived from the chemical mass balance (CMB), target transformation factor analysis (TTFA) and multiple linear regression (MLR) methods agree well with each other. The contributions from emission sources exhibit large variations in particle size with temporal and spatial differences. On average, the major contributors of PM₁₀ aerosol mass in Brisbane include: soil/road side dusts (25% by mass), motor vehicle exhausts (13%, not including the secondary products), sea salt (12%), Ca-rich and Ti-rich compounds (11%, from cement works and mineral processing industries), biomass burning (7%), and elemental carbon and secondary products contribute to around 15% of the aerosol mass on average. The major sources of PM_2.5 aerosols at the Griffith University (GU) site (a suburban site surrounded by forest area) are: elemental carbon (24% by mass), secondary organics (21%), biomass burning (15%) and secondary sulphate (14%). Most of the secondary products are related to motor vehicle exhausts, so, although motor vehicle exhausts contribute directly to only 6% of the PM_2.5 aerosol mass, their total contribution (including their secondary products) could be substantial. This pattern of source contribution is similar to the results for Rozelle (Sydney) among the major Australian studies, and is less in contributions from industrial and motor vehicular exhausts than the other cities. An attempt was made to estimate the contribution of rural dust and road side dust. The results show that road side dusts could contribute more than half of the crustal matter. More than 80% of the contribution of vehicle exhausts arises from diesel-fuelled trucks/buses. Biomass burning, large contributions of crustal matter, and/or local contributing sources under calm weather conditions, are often the cause of the high PM₁₀ episodes at the GU site in Brisbane.