Average TSP Research Articles

Total Suspended Particulate Matter (TSP)-Bound Carbonaceous Components in a Roadside Area in Eastern Indonesia

To evaluate carbonaceous components in the ambient air in the eastern region of Indonesia, 35 Total Suspended Particulate Matter (TSP) samples were collected on four characteristic roadsides on Sultan Alauddin Street, in Makassar City, using a high-volume air sampler. The average TSP concentration was 279.7 μg/m3, which exceeded both the National Ambient Air Quality Standard (NAAQS) of Indonesia and the World Health Organization (WHO) standards. The highest concentration reached 838.6 μg/m3 in the GR (gravel) site, which had the highest number of vehicles and was near a U-turn. TSP concentration was higher during peak hours (morning and late afternoon) than off-peak hours (noon). The main component of the total carbon (TC) fraction was organic carbon (OC), which showed a strong correlation with elemental carbon (EC) (r values for the morning, noon, and late afternoon were 0.89, 0.87, and 0.97, respectively), indicating that the carbon components were derived from common sources. TSP had a strong correlation with carbon components, except for char-EC. OC vs. soot-EC and EC vs. soot-EC also correlated well, suggesting the dominant influence of vehicle exhaust emissions. Non-exhaust emissions had a slight influence during peak hours, particularly at the GR site.

Regional organic matter and mineral dust are the main components of atmospheric aerosols over the Nam Co station on the central Tibetan Plateau in summer

The transport of air pollutants from areas surrounding the Tibetan Plateau (TP) has recently been studied. However, the major sources of atmospheric total suspended particulate matter (TSP) on the central TP remain unclear due to a lack of in-situ observations on aerosol physico-chemical properties. Therefore, to quantitatively investigate the physico-chemical properties and reveal the major sources of atmospheric aerosols, a comprehensive field campaign was conducted at the site of Nam Co from August 6 to September 11, 2020. Aerosol loading was low during the campaign with average TSP mass concentration, scattering coefficient at 550 nm, and absorption coefficient at 670 nm being 10.11 ± 5.36 μg m−3, 1.71 ± 1.36 Mm−1, and 0.26 ± 0.20 Mm−1, respectively. Organic matter (63.9%) and mineral dust (27.8%) accounted for most of the TSP mass concentrations. The average scattering Ångström exponent of 0.59 ± 0.14 reflected the influence of mineral dust, and the elemental fractions and the results of enrichment factor illustrated that crustal materials were the main contributors of mineral dust. The organic to elemental carbon ratio of 15.33 is probably caused by the aging that occurs during the transport of aerosols. The strong correlation between organic carbon and Ca2+ and the results of the electron microscopy analysis of single particles indicated that organic carbon and mineral dust had the same sources; however, the weak relation between mineral dust and wind speed indicated that local wind erosion was not the main contributor to the mineral dust. The potential source contribution function further illustrated that the summertime TSP in the central TP was mainly characterized by background biomass and mineral dust aerosols originating regionally from the ground within the TP.

Measurements and predictions of ambient air particulates dry depositions at Taichung Shuinan Economic and Trade Park (T.S.E.T.P) during summer and autumn seasons

This study collected ambient air particulate concentrations and dry depositions at Taichung Shuinan Economic and Trade Park (T.S.E.T.P.) sampling site. The global dry depositions model was applied with known particle sizes, pollutant concentrations in ambient air pollutants dry deposition estimates at T.S.E.T.P. site in Central Taiwan. Statistical analysis of the correlated relationships among ambient air particulate concentration, dry depositions, and dry deposition velocities with respect to the meteorological conditions at T.S.E.T.P. site was also conducted. The results indicated that the average dry deposition fluxes were 377.81 µg/m2*min, the average TSP concentrations were 41.53 µg/m3, and the average dry depositions velocity (Vd ) was 15.26 cm/s. In addition, 40 μm was selected as the best ambient air particulate size for the calculated dry deposition velocities to estimate ambient air dry deposition fluxes using the Global model at this T.S.E.T.P. sampling site. Moreover, ambient air particulates concentrations were higher in the fall season than that of the summer season. Sincepollutants parcels were not easily diffused during the fall season because of the low mixed atmospheric layer in this season. Therefore, atmospheric particulates concentrations were higher from the northern side than that of southern side in this study. Furthermore, wind speed V.S. particulate dry depositions and wind V.S. dry depositions velocity displayed a moderate correlated relationship, while particulate dry depositions V.S. particulate dry depositions velocity presented the highest correlated relationship at this T.S.E.T.P. sampling site. However, particulate dry depositions and dry depositions velocity presented significant differences. Finally, particulate dry depositions and dry depositions velocity were not only highly correlation related but also displayed significant differences at the T.S.E.T.P. sampling site.

Particulate bound mercury Hg(p) concentrations, compositions and dry depositions study around mixed and agricultural (MA) sites

TSP concentrations in ambient air and dry deposition were measured at an (agricultural) sampling site in Taiping. The TSP concentrations are compared with those in the other counties in Asia. Statistical differences between the TSP concentrations and dry depositions in Luliao district (mixed site) and Taiping district (agricultural site) are discussed. Ambient air particulate-bound mercury Hg(p) concentrations in TSP and dry depositions are analyzed and discussed. Mean concentrations and dry depositions of Hg(p) were tested at two characteristic sampling sites – Luliao (mixed) and Taiping (agricultural) districts. Finally, the measured ambient air particulate-bound mercury Hg(p) concentrations and dry depositions were compared with those in other regions of the world. TSP concentrations were highest in March at 49.7 (μg/m3) and lowest in June at 15.85 (μg/m3). Dry deposition was highest in March at 1336.41 (μg/m2*min) and lowest in June at 15.85 (μg/m2*min). The highest average dry depositions and TSP concentrations were measured in March. The particulate-bound mercury Hg(p) concentrations in TSP were higher at the Luliao sampling site (0.384 μg/m3) than at the Taiping (0.078 μg/m3) sampling site. The mean Hg (p) dry deposition was higher in Taiping (0.665 μg/m2*min) than in Luliao (0.387 μg/m2*min). The mean concentrations of TSP differed between Luliao (mixed) and Taiping (agriculture) sampling sites, but the mean dry depositions did not. The differences between TSP concentrations and dry depositions might have arisen from the fact that most of the particulate-bound mercury Hg(p) at the Taiping (agriculture) sampling site had natural sources while that at the Luliao (mixed) sampling site had anthropogenic sources. The average ratios of highest to lowest particulate concentrations exceeded seven in urban areas; exceeded 1.5 in areas of traffic, and approached (one OR unity OR 1) for all particulate sizes.

Air Pollution Levels by Re-suspended and Airborne Dust Due to Traffic Movement at the Main High Traffic Crossroads of Hilla City, Iraq

This research includes a monitoring and an evaluation of the air pollution levels generated by the re-suspended and airborne dust due to traffic movement at the main busy crossroads of Hilla City, Nader Crossroad and Al-Thowra Crossroad, Iraq. The re-suspended dust is one of the most important contributors towards overall atmospheric pollution, especially when the roads are unpaved or under maintenance with high traffic load such as Nader Crossroad, which was under maintenance to construct a bridge on it. The concentrations of the total suspended particulate matters were determined at the two locations using portable air sampler during traffic rush hour on sunny moderated weekdays for four months, December 2011, February 2012, April 2012, and May 2012. The results have confirmed the contribution of the unpaved roads in air pollution. The results showed that the average TSP levels at Nader Crossroad was higher than the average TSP levels at Al-Thowra Crossroad during the total period of the study in which the minimum TSP level at Nader Crossroad was 5676.67 μg/m3, which was higher than the maximum TSP level at Al-Thowra Crossroad, 4096.41 μg/m3. In addition, the re-suspended dust concentrations that were measured in this study and ranged from 426.06 to 9348.95 μg/m3 are much higher than the American Environmental Protection Agency acceptable limits of national ambient air quality standards for the particulate matter.

Concentrations of particulates and metallic elements in slow wind (average 1.5 m/s) in the winter season

ABSTRACTConcentrations of fine particulates (PM2.5) and metallic elements at three sites in central Taiwan (an urban site, a science park, and a site close to traffic), where the mean wind speed was only 1.5 m/s, were monitored and analyzed. The urban site had the lowest TSP and PM2.5 particulate concentrations in winter. The mean concentrations of metallic elements Ni, Pb, and Cr in PM2.5 exceeded those in TSP at the three characteristic sampling sites in winter. A northeasterly monsoon, slowly moving northern cold air masses, and wind with a low average speed (1.5 m/s) dominated during the sampling period. Atmospheric diffusion was generally low, causing large amounts of local atmospheric pollutants to accumulate. The concentrations of metallic elements that were attached to particulates (PM2.5) increased significantly during the winter season. However, the concentrations of particulate pollutants in ambient air declined throughout the winter. The average TSP and PM2.5 particulate concentrations in ambient air that were obtained in this study with a low average wind speed (1.5 m/s) were about 0.48% and 0.41% lower, respectively, than those obtained in a previous study with a higher average wind speed (of > 3 m/s). The mean low wind speed (1.5 m/s) was the main factor that was responsible for the concentrations of pollutants in ambient air during the winter season.

Chemical Characterization and Source Apportionment of Atmospheric Particles Across Multiple Sampling Locations in Faisalabad, Pakistan

Atmospheric particles (total suspended particles, TSPs) mass samples (288) were collected by high volume samplers at nine sampling locations in Faisalabad, Pakistan from May 2012 to April 2013. These TSP mass samples were subjected to gravimetric and quantitative chemical analyses for determining trace elements (Pb, Cd, Ni, Zn, Cu, Fe) using atomic absorption spectroscopy and water‐soluble cations (Ca2+, Mg2+, Na+ and K+, NH4+) and anions (Cl−, SO42− , and NO3−) by ion chromatography. The average TSP mass and elemental concentrations at all locations were found to be highest during the dry and lowest during the wet season. The crustal elements Ca, Fe, Mg, and Na were the largest contributors to TSP mass while elements of anthropogenic origin Pb, Cd, Ni, Cu, and Zn had relatively lower concentrations and also showing a high spatial variation. The concentration of TSP and elements exhibited the maxima at the sampling locations characterized by intensive industrial and vehicular activities. The wind rose analysis and the UNMIX model applied to chemical speciation data both identified the same three primary sources of TSP: power plant/refinery, brick kilns, and roadways. The normalized dot product was successfully used to quantify the similarity between different source profiles extracted from UNMIX model. The coupling of UNMIX with wind direction analysis complemented each other and provided a complete assessment of source contributions and locations.

Probability distribution and extreme value analysis of total suspended particulate matter in Kuwait

Probability distribution and extreme value analysis were carried out on total suspended particulate matter (TSP) in Kuwait. The measured TSP data, available for about 10 years from three different locations in Kuwait, viz., Managhesh, Shuwaikh, and Kuwait City were used. For probability distribution analysis, four theoretical distributions were considered, namely Rayleigh, exponential, Gumbel, and log-normal distribution. Based on the study, it was found that log-normal distribution represented the measured daily average TSP value in Kuwait. The expected extreme daily average TSP values for 10-, 25-, 50-, and 100-year return periods were estimated based on Gumbel, exponential, and Weibull extreme value distributions for these three locations. For 100-year return period, the expected TSP values in Managhesh were 5270, 5920, and 4584 μg/m3, based on Gumbel, exponential, and Weibull extreme value distributions, respectively. For the same return period, the expected TSP values in Shuwaikh were 11,255, 12,592, and 8771 μg/m3, and in Kuwait City, 7109, 8136, and 6494 μg/m3, based on Gumbel, exponential, and Weibull extreme value distributions, respectively. During an extreme dust storm in Kuwait, an extreme TSP of 9619 μg/m3 was recorded on 25 March 2011. The results of this study are an important input to understand the probability distribution of TSP and also for the analysis on the impact of TSP on the socioeconomic development and on the respiratory health issues in Kuwait.

Particulates and Metallic Elements Monitoring at Two Sampling Sites (Harbor, Airport) in Taiwan

This study characterized the dry deposition flux and dry deposition velocity (Vd) of metallic elements attached on particulate matter. Specifically, large particles (>10 μm), coarse particles (10 μm∼2.5 μm), and fine particles (<2.5 μm) were studied at the Gong Ming Junior High School (Taichung Airport) and Taichung Harbor sampling sites in central Taiwan. Ambient air samples were collected to determine total suspended particulate matter (TSP), dry deposition plate (DDP), Vd, coarse particulate matter (PM2.5–10) and fine particulate matter (PM2.5), and metallic elements concentrations at the Airport and Taichung Harbor sites between June 17, 2013, and November 14, 2013. The results revealed that the average TSP, DDP, Vd, PM2.5–10, and PM2.5 particulate at the Airport were 54.55 (μg/m3), 902.25 (μg/m2-min), 17.11 (m/sec), 0.003 (μg/m3), and 0.010 (μg/m3), respectively; while these values at Taichung Harbor were 63.66 (μg/m3), 539.69 (μg/m2-min), 9.94 (m/sec), 0.003 (μg/m3), and 0.014 (μg/m3), respectively. In addition, the results showed that the average Cu and Pb concentrations were higher than Cr, Ni, and Cd for both the airport and harbor sampling sites. Furthermore, Cr, N, Cu, Cd, and Pb had the highest average concentrations versus those reported for other study areas, with one exception: The results obtained in Kacanik, Kosovo, during 2005. The average metallic elements concentrations order was Cu > Pb > Cr > Ni > Cd.

Ambient TSP concentration and dustfall variation in Urumqi, China

Total suspended particulate (TSP, particle diameter≤100 μm) was the dominant air pollutant and significantly influenced local air quality. In this paper, we investigated the interannual and seasonal variations of TSP and dustfall of the atmosphere over Urumqi, the capital city of Xinjiang Uygur autonomous region, northwestern China, basing on environmental monitoring records and meteorological data from 1986–2012. The results showed that during the study period, annual average TSP concentration decreased from 716 to 260 μg/m3, with an average level of 422.9 μg/m3, while dustfall intensity reduced from 350.4 to 166.6 t/(km2·a), with an average level of 259 t/(km2·a). Over 50% of the annual pollution days were induced mainly by TSP. Spring and winter had relatively higher dustfall intensities, and dense traffic and residential areas had the highest dustfall intensities in the Urumqi metropolitan area. With an annual average precipitation of less than 300 mm, atmospheric particulates in Urumqi could be hardly removed through wet deposition. During spring and summertime prevailing winds from northwest and northeast could carry aeolian dust particles from sandy deserts to Urumqi. Aeolian dusts from deserts would remain to be a priority regarding air pollution control in arid oasis cities.

The National Air Emissions Monitoring Study’s Southeast Layer Site: Part II. Particulate Matter

Abstract. The National Air Emissions Monitoring Study (NAEMS) was established by the U.S. EPA and the U.S. livestock and poultry industries to address the lack of scientific air emission data needed for properly assessing compliance with federal air laws and regulations. A North Carolina egg layer farm (NC2B) was one of 20 NAEMS monitored farms. Emission rates of particulate matter (PM 2.5 , PM 10 , and TSP) from two high-rise layer houses at NC2B were determined based on continuous measurements of PM concentrations and house ventilation rates over a two-year period. The overall average PM 2.5 emission rate of both houses combined was 0.37 ±3.06 mg d -1 hen -1 with no significant difference between houses. The average PM 10 emission rates were 16.2 ±13.7 and 19.3 ±15.9 mg d -1 hen -1 from houses 3 and 4, respectively, and 17.8 ±14.9 mg d -1 hen -1 for both houses combined. The average TSP emission rates were 39.1 ±32.8 and 47.1 ±37.6 mg d -1 hen -1 for houses 3 and 4, respectively, and 43.1 ±35.5 mg d -1 hen -1 for both houses combined. The median hourly mean emission rates were 0.61, 14.7, and 31.7 mg d -1 hen -1 from house 3 and 0.72, 17.1, and 42.4 mg d -1 hen -1 from house 4 for PM 2.5 , PM 10 , and TSP, respectively. Significant temporal variations in PM concentrations and emissions were observed. Significant differences in PM concentrations were also observed between the manure pit and layer room. The PM emissions exhibited significant correlations with hen activity and house exhaust air temperature. An empirical PM emissions model was developed based on multiple regression analysis to predict PM emissions from this monitoring site.

Indoor Particulate Matter in Different Residential Areas of Alexandria City, Egypt

Particulate matter is one of the most important indoor air pollutants that could cause a number of adverse health effects. Quantification of total suspended particulate matter (TSP) in homes in the city of Alexandria was carried out. In the present study, 15 of the 21 homes showed a higher average indoor TSP concentration than the outdoor sample, and the median indoor/outdoor ratio was 1.08. Moreover, the outdoor and the mean indoor TSP concentrations were found to correlate significantly. Concentrations of indoor particulate matter were found to be influenced by indoor sources and human activities as well as outdoor particles.

Indoor/outdoor relationship of trace metals in the atmospheric particulate matter of an industrial area

Present study is based on the measurement and monitoring of indoor and outdoor atmospheric particulate matter from an industrial area (Wah Cantt, Pakistan). The particulate samples are collected on glass fiber filter paper using high volume air sampler. Trace metals (Cd, Co, Cr, Cu, Fe, Mn, Pb, Sb and Zn) in the particulate samples are estimated by atomic absorption spectrometry. On the average TSP level is significantly higher in outdoor atmosphere than indoor, and both of them are higher than WHO and USEPA standards. The distribution of trace metals is considerably diverse in indoor and outdoor particulates. Average concentrations of Fe, Zn, Co, Cr and Mn are significantly higher in outdoor particulates, whereas Cu and Pb levels are considerably higher in the indoor particulates. Source apportionment carried out by PCA and CA is diverse in indoor/outdoor particulates and the major pollution sources identified are industrial activities, automobile emissions and soil derived dust. Among the trace metals, Cd, Sb, Zn, Pb and Co are found to be highly enriched in the atmospheric particulate matter. The present atmospheric trace metals levels are also compared with those reported from other regions around the world, and are many-folds higher than previously reported results.

Pollution abatement for improving air quality of Tangshan municipality, China: a perspective of urban-airshed carrying-capacity concept

This paper presents a perspective of Urban-Airshed Carrying-Capacity (UACC) concept for air pollution abatement in Tangshan Municipality, China. A 3D Multi-Box Air Quality Prediction (3DMBAQP) model was developed for predicting daily average SO2, TSP and PM10 concentrations in each sub-box of different municipal Function Zones (FZs). A 6-step procedure was designed to determine the UACC levels for each pollutant. The abatement amounts for each zone can then be obtained. The study results can be used by municipal authorities to develop effective initiatives to allocate abatement amounts among different emission contributors and thus improve local air quality in a long run.

The water-soluble fraction of carbon, sulfur, and crustal elements in Asian aerosols and Asian soils

We quantified the water-soluble species in 24 h average TSP (Dunhuang and Gosan) and PM1.0 (Gosan only) samples associated with the Spring 2001 Asian Dust season. Samples were analyzed for water-soluble organic carbon, water-soluble sulfur, and water-soluble crustal elements, as well as their bulk chemical composition. Water-soluble organic carbon in Gosan accounted for 28–83% (average=63%) of the particle-phase TSP total organic carbon, and 1–69% (average=23%) of the particle-phase PM1.0 organic carbon. Water-soluble sulfur, primarily in the form of sulfate, accounted for 2–22% of the TSP mass in Gosan, and 0.9–11% of the TSP mass in Dunhuang. The absolute concentrations and the soluble fraction of crustal elements in TSP samples collected at Gosan were found to correlate with the air mass source region as determined by back-trajectory analysis. For example, elevated levels of water-soluble sodium, potassium, and calcium were observed during dust events. These observations are likely the result of differences in anthropogenic sources, mineralogical composition of resuspended crustal materials, and atmospheric processing of the aerosols. Experiments were conducted using Asian soil samples to study the impact of acidification by nitric acid vapor on the solubility of crustal elements present in Asian desert and non-desert dusts. These experiments demonstrated that gaseous nitric acid attack leads to significant increases (>100% increase) in water-soluble calcium, magnesium, aluminum, manganese, and iron, while little or no increases in water-soluble sodium and potassium were observed in the soils.

Carbonaceous aerosols in MABL of Bay of Bengal: Influence of continental outflow

Elemental carbon (EC) and organic carbon (OC) concentrations along with the total suspended particulate matter (TSP) have been measured in the marine atmospheric boundary layer (MABL) of Bay of Bengal (BoB) during the spring inter-monsoon season (19 March–11 April 2006). The abundance of EC (range: 0.12–0.66μgm−3; Av: 0.4μgm−3) is found to be only ∼2% of TSP, whereas particulate organic matter (calculated based on OC ranging from 0.3 to 5.5μgm−3, Av. 1.9μgm−3) contributes nearly 11% of the average TSP (22μgm−3). The spatial distribution of carbonaceous species shows a higher concentration in the northern Bay and decreases towards the central and south-eastern region suggesting the advective transport of continental pollutants to the MABL. The influence of anthropogenic sources is further supported by the elevated levels of nss-SO42- (4.7–11μgm−3) in the northern region. A comparison with the data collected during February 2003 (late NE-monsoon) from the same region consistently demonstrates a similar feature of the continental outflow, but a factor of 2–3 higher concentrations of carbonaceous species (EC: 0.4–3.4μgm−3; OC: 2–8μgm−3). OC/EC ratios were 6.5 and 7.4 for sampling seasons in 2003 and 2006 and for nss-SO42-/EC ratios were 6 and 15 respectively. The significantly higher abundances of EC during late NE-monsoon (February) demonstrate the strong influence of polluted air masses in the MABL decreasing rapidly with the shift in the wind regimes (March–April).

Atmospheric Pollution Caused by Particulate Metals in Central Taiwan

Dividing measured fluxes by measured airborne concentrations for varying particle size range identified dry deposition velocities of various metals. This study attempts to identify the dry deposition flux and dry deposition velocity of metallic particulates among large inhalable particles (> 10 μ m [PM10]), coarse particles (10–2.5 μ m [PM2.5 − 10]), and fine particles (< 2.5 μ m [PM2.5) at the Taichung harbor (TH) and Taichung airport (TA) sampling sites in central Taiwan from September to December in 2004 and 2005, respectively. The results indicate that dust, vehicle emissions, and marine salts are the principal sources of coarse and fine particulates at the TH sampling site. The analytical results also suggest that the average concentrations of Fe, Mn, Cu, Zn, Cr, and Mg in the total suspended particulate fraction and in coarse particles are highest at the TH sampling site. Additionally, measurement data demonstrate that the average concentrations of Mn, Cu, Zn, Cr, and Mg are also high at the TH site for all particle sizes. Both Mn and Pb concentrations resemble each other throughout all particle sizes. Results of this study further demonstrate that average TSP or PM10 concentrations measured in this study were less than Taiwan Environmental Protection Agency standard.

A gaussian-box modeling approach for urban air quality management in a northern chinese city—I. model development

A Gaussian-box modeling approach was presented in this paper to examine the urban air quality due to multiple point- and area-source emissions in the northern Chinese city of Fengnan, which is associated with a deteriorated air quality as a consequence of industrialization and rapid urban growth. A 3-D multi-box (3DMB) air quality model was developed to predict air quality due to area-source emissions. It improved upon the conventional box models by allowing consideration of more details in spatial variations of emission sources and meteorological conditions. The modeling domain was divided into various layers within the mixing height, while each layer was associated with a number of sub-boxes. A multi-source and multi-grid Gaussian modeling approach was then applied to predict the air quality in different sub-boxes that are associated with multiple point-source emissions. Thus the Gaussian-box modeling approach could effectively simulate impacts of both area- and point-source emissions but also reflect more details of the spatial variations in source distributions and meteorological conditions. This modeling approach was employed to predict daily average SO2, TSP and PM10 concentrations for each sub-box during the heating and non-heating seasons, respectively. The analysis of the mean normalized error of the modeling results demonstrates the feasibility and applicability of the developed method, and the presented method could provide more useful and scientific bases for developing effective urban air quality control and management strategies.

Ambient air quality of two metropolitan cities of Pakistan and its health implications

The present study reports findings on TSP loading in the ambient air of two major cities in Pakistan – Karachi and Islamabad. Data for TSP were collected at one site in Karachi and two in Islamabad between 10 December 1998 and 08 January 1999. This article reports one of the highest TSP loadings recorded so far in any megacity of the world. During the study period, average daily TSP concentrations at the Karachi site ranged from 627 to 938 μg m −3 with a mean of 668 μg m −3. On four occasions TSP concentrations were >1000 μg m −3 (range 1031–1736 μg m −3). At the Islamabad sampling site in close proximity to the city's industrial sector, daily TSP concentrations varied in the range of 428–998 μg m −3 (mean 691 μg m −3). Even at a relatively remote site of the city (Saidpur), TSP loading was high (range 145–448 μg m −3; mean 275 μg m −3). By virtue of the WHO definition, the 24-h average TSP concentrations in a busy commercial site in Karachi and in the vicinity of an industrial sector in Islamabad were in “exceedance” by a factor of 4–8. At Saidpur, the remote site, the 24-h average TSP loading exceeded the WHO guideline of 120 μg m −3 by a factor of 1.2–3.7.

The study of Central Taiwan particles concentration variations during earthquake period

Ambient particle concentration was taken on the traffic sampling site over the Chung-Chi Road over the bridge (CCROB) in front of Hungkuang Institute of Technology (HKIT). The sampling time was from August 1999 to December 1999. During the sampling period, Taiwan's biggest earthquake in more than a century registered 7.3 on the Richter scale (Taiwan Chi-Chi Earthquake). Besides, there are more than 20,000 aftershocks following the Taiwan Chi-Chi Earthquake within 3 months. Thus, the mass concentration of particles with aerodynamic diameters smaller than 2.5 μm (PM 2.5) and PM 2.5–10 was also collected then compared with the total mass concentration of suspended particles (TSP) in this study. The average TSP, PM 2.5–10, and PM 2.5 concentrations are 106, 24.6, and 58.0 μg/m 3, respectively, after the Taiwan Chi-Chi Earthquake. The average TSP concentrations before and after Taiwan Chi-Chi Earthquake were 69.6 and 127 μg/m 3, respectively. In addition, statistical analysis of the PM 10 data from this study and EPA in 1999 yielded a T statistic of 0.147, which is smaller than t (0.975,18)=2.101. It is indicated that there was no significant difference. So, the PM 10 concentrations measured after Taiwan Chi-Chi Earthquake in this study were also greater than those data previously obtained from Taiwan EPA in the same region of this area. The relationships between TSP, PM 10, PM 2.5–10, and PM 2.5 particle concentrations and wind speed ( R 2) are .77, .59, .58, .58, respectively. And the ratios of PM 2.5/PM 2.5–10, PM 2.5/PM 10, and PM 10/TSP are 221%, 67.2%, 58.0%, respectively. The average ratios of PM 2.5/PM 2.5–10 and PM 2.5/PM 10 increase by about 120% and 17%. It indicated that the fine-particles concentration increases compared to the coarse-particles concentration after 921 Taiwan Chi-Chi Earthquake. And the proposed reasons are that local motor vehicle emissions combined the fine particles transported from the Chi-Chi epicenter. More importantly, the wind direction was mainly blown from southeastern part. These two main factors enhance the fine-particles concentration in this area.