The concentration of total suspended particles (TSP) and nanoparticles (PM0.1) over Hat Yai city, Songkhla province, southern Thailand was measured in 2019. Organic carbon (OC) and elemental carbon ...(EC) were evaluated by carbon aerosol analyzer (IMPROVE-TOR) method. Thirteen trace elements including Al, Ba, K, Cu, Cr, Fe, Mg, Mn, Na, Ni, Ti, Pb, and Zn were evaluated by ICP-OES. Annual average TSP and PM0.1 mass concentrations were determined to be 58.3 ± 7.8 and 10.4 ± 1.2 µg/m3, respectively. The highest levels of PM occurred in the wet season with the corresponding values for the dry seasons being lower. The averaged OC/EC ratio ranged from 3.8–4.2 (TSP) and 2.5–2.7 (PM0.1). The char to soot ratios were constantly less than 1.0 for both TSP and PM0.1, indicating that land transportation is the main emission source. A principal component analysis (PCA) revealed that road transportation, industry, and biomass burning are the key sources of these particles. However, PM arising from Indonesian peatland fires causes an increase in the carbon and trace element concentrations in southern Thailand. The findings make useful information for air quality management and strategies for controlling this problem, based on a source apportionment analysis.
The characteristics of the particles of the smoke that is emitted from the burning ofbiomass fuels were experimentally investigated using a laboratory-scale tube furnace and different types of ...biomass fuels： rubber wood, whole wood pellets and rice husks. Emitted amounts of particles, particle-bound polycyclic aromatic hydrocarbons （PAHs） and water-soluble organic carbon （WSOC） are discussed relative to the size of the emitted particles, ranging to as small as nano-size （〈70 nm）, and to the rate of heating rate during combustion, differential thermal analysis （DTA） and thermogravimetric analysis （TG） techniques were used to examine the effect of heating rate and biomass type on combustion behaviors relative to the characteristics of particle emissions. In the present study, more than 30% of the smoke particles from the burning ofbiomass fuel had a mass that fell within a range of 〈 100 nm. Particles smaller than 0.43 μm contributed greatly to the total levels of toxic PAHs and WSOC. The properties of these particles were influenced by the fuel component, the combustion conditions, and the particle size. Although TC--DTA results indicated that the heating rate in a range of 10-20℃did not show a significant effect on the combustion properties, there was a slight increase in the decomposition temperature as heating rate was increased. The nano-size particles had the smallest fraction of particle mass and particle-bound PAHs, but nonetheless these particles registered the largest fraction of particle-bound WSOC.
Many of the current atmospheric environmental problems facing Thailand are linked to air pollution that is largely derived from biomass burning. Different parts of Thailand have distinctive sources ...of biomass emissions that affect air quality. The main contributors to atmospheric particulate matter (PM), especially the PM2.5 fraction in Thailand, were highlighted in a recent study of PM derived from biomass burning. This review is divided into six sections. Section one is an introduction to biomass burning in Thailand. Section two covers issues related to biomass burning for each of the four main regions in Thailand, including Northern, Northeastern, Central, and Southern Thailand. In northern Thailand, forest fires and the burning of crop residues have contributed to air quality in the past decade. The northeast region is mainly affected by the burning of agricultural residues. However, the main contributor to PM in the Bangkok Metropolitan Region is motor vehicles and crop burning. In Southern Thailand, the impact of agoindustries, biomass combustion, and possible agricultural residue burning are the primary sources, and cross-border pollution is also important. The third section concerns the effect of biomass burning on human health. Finally, perspectives, new challenges, and policy recommendations are made concerning improving air quality in Thailand, e.g., forest fuel management and biomass utilization. The overall conclusions point to issues that will have a long-term impact on achieving a blue sky over Thailand through the development of coherent policies and the management of air pollution and sharing this knowledge with a broader audience.
Atmospheric aerosols pose a significant global problem, particularly in urban areas in developing countries where the rapid urbanization and industrial activities degrade air quality. This study ...examined the spatiotemporal variations and trends in aerosol optical depth (AOD) at a 550 nm wavelength, alongside key meteorological factors, in Kabul, Afghanistan, from 2000 to 2022. Using the Google Earth Engine geospatial analysis platform, daily AOD data were retrieved from the Moderate Resolution Imaging Spectroradiometer to assess monthly, seasonal, and annual spatiotemporal variations and long-term trends. Meteorological parameters such as temperature (T), relative humidity (RH), precipitation (PCP), wind speed (WS), wind direction, and solar radiation (SR) were obtained from the Modern Era Retrospective Analysis for Research and Applications. The Mann–Kendall test was employed to analyze the time-series trends, and a Pearson correlation matrix was calculated to assess the influence of the meteorological factors on AOD. Principal component analysis (PCA) was performed to understand the underlying structure. The results indicated high AOD levels in spring and summer, with a significant upward trend from 2000 to 2022. The findings revealed a positive correlation of AOD value with T, RH, WS, and PCP and a negative correlation with SR. The PCA results highlighted complex interactions among these factors and their impact on the AOD. These insights underscore the need for stringent air quality regulations and emission control measures in Kabul.
Northern Thailand has long been severely affected by haze from biomass burning containing fine and ultrafine aerosols in the dry period. The carbonaceous PM0.1 comprising elemental carbon (EC) and ...organic carbon (OC) collected during the haze and non-haze periods in Chiang Mai, Thailand was investigated. The PM0.1 levels during the haze periods were about 3 times higher than the non-haze periods, a significant increase. PM0.1 concentration was strongly correlated with atmospheric relative humidity and the number of forest fire hotspots. Carbonaceous aerosol characteristics in PM0.1 were analyzed with the thermal/optical transmittance (TOT) method following the IMPROVE protocol. The concentrations of OC and EC, distribution of OC and EC and OC/EC ratios in PM0.1 were evaluated. Average OC and EC mass concentrations in PM0.1 were 6.8 ± 2.7 and 1.4 ± 0.5 µg m–3 during the haze periods, significantly higher than those during the non-haze periods; 1.9 ± 0.9 and 0.5 ± 0.2 µg m–3. The OC/EC ratio increased linearly with the number of hotspots. This indicated significant contribution from biomass burning to the PM0.1. This was strongly supported by the 48-hr backward trajectory simulation, that indicated both domestic and transboundary aerosol transports. Because both organic and elemental carbon are the light-absorbing carbonaceous aerosols, the increase during the haze periods contributed to regional air quality and climate. This study enhances the understanding of PM0.1 behavior in Chiang Mai, Thailand, during the haze periods in upper southeast Asia.
Air sampling for 12 h diurnal and nocturnal periods was conducted at two monitoring sites with different characteristics in Jambi City, Sumatra Island, Indonesia. The sampling was done at a roadside ...site and a riverside site from 2–9 August, and from 7–13 August in 2019, respectively. A cascade air sampler was used to obtain information on the status, characteristics and behavior of airborne particles with a particular focus on the ultrafine fraction (PM0.1). The number of light vehicles was best correlated with most PM size categories, while those of heavy vehicles and motorcycles with the 0.5–1 μm and with >10 μm for the nocturnal period, respectively. These findings suggest that there is a positive influence of traffic amount on the PM concentration. Using carbonaceous parameters related to heavy-vehicle emissions such as EC and soot-EC, HV emission was confirmed to account for the PM0.1 fraction more clearly in the roadside environment. The correlation between OC/EC and EC for 0.5–1 μm particles indicated that biomass burning has an influence on both in the diurnal period. A possible transboundary influence was shown as a shift in the PM0.1 fraction characteristic from “urban” to “biomass burning”.
In this study, as the first step in mitigating contamination by PM0.1, particles with diameters less than 0.1 μm, the current air pollution situation in Indonesia was investigated with respect to ...particulate matter (PM), especially regarding the status and characteristics of PM0.1. Air sampling in different size ranges down to PM0.1 was conducted at roadsides, at a school adjacent to a road, an industrial area and an area near a volcano in North Sumatera Province. Analyses were conducted for carbonous components (OC, EC, TC, WSOC and WISOC), and ions including oxalate in the PM0.1 fraction. We identified PM2.5 and PM10 mass concentrations in the area of the city that exceeded WHO guidelines. From the chemical components in the PM0.1 fraction, we found that WISOC, NO3− and soot-EC were the most common components, suggesting that local traffic is a contributor and another group consisting of K+, SO42− and WSOC suggesting the occurrence of biomass burning related to local industrial and rural sources.
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•Serious air pollution in the PM10/PM2.5/PM0.1 was found in the Medan city area.•All of the test sites including a school, a roadside and an industrial area were polluted.•Carbonaceous compounds were major components in PM0.1 at all the sites.•Water-insoluble carbon was related with emission from local traffic.•Water-soluble carbon was significantly originated from biomass burning.
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.
Size-segregated particulate matter (PM) including the PM0.1 fraction, particles ≤0.1 µm, was monitored during the rainy and dry seasons at three different cities in Sumatra island, Indonesia in 2018. ...In order to identify possible emission sources, carbonaceous components in the particles collected by a cascade air sampler that is capable of collecting PM0.1 particles were analyzed by applying a thermal/optical reflectance (IMPROVE-TOR) protocol. The PM0.1 levels in the Jambi and Pekanbaru areas were similar to those in large cities in East Asia, such as Bangkok and Hanoi. During the rainy season, local emissions in the form of vehicle combustion were the main sources of PM. The influence of peatland fires in the dry season was more significant in cities that are located on the east coast of Sumatra island because of the larger number of hotspots and air mass trajectories along the coast. A clear increase in the carbonaceous profiles as OC, TC, and OC/EC ratios in the dry season from the rainy season was observed, particularly in fine fractions such as PM0.5–1. In both seasons, EC vs. OC/EC correlations and soot-EC/TC ratios showed that the PM0.1 fraction in Sumatra island was heavily influenced by vehicle emissions, while the effect of biomass burning was more sensitive with respect to the PM0.5–1 fraction, particularly in Jambi and Pekanbaru sites during the dry season.
A cascade impactor type sampler equipped with an inertial filter was used to collect size-segregated particles down to ultrafine particles (UFPs or PM0.1) on Batam Island in Sumatra, Indonesia, ...bordered by Singapore and Malaysia during a wet and the COVID-19 pandemic season in 2021. Carbonaceous species, including organic carbon (OC) and elemental carbon (EC), were analyzed by a thermal/optical carbon analyzer to determine the carbon species and their indices. The average UFP was 3.1 ± 0.9 μg/m3, which was 2–4 times lower than in other cities in Sumatra during the same season in the normal condition. The PMs mass concentration was largely affected by local emissions but long-range transportation of particles from Singapore and Malaysia was also not negligible. The air mass arrived at the sampling site passed the ocean, which introduced out clean air with a low level of PMs. The backward trajectory of the air mass and the largest fraction of OC2 and OC3 in all sizes was identified as being transported from the 2 above countries. OC is the dominant fraction in TC and the ratio of carbonaceous components indicated that origin of all particle sizes was predominantly vehicle emissions. UFPs were dominantly emitted from vehicles exhaust emission, while coarser particles (>10 μm) were influenced by the non-exhaust emissions, such as tire wear. Other particles (0.5–1.0; 1.0–2.5; and 2.5–10 μm) were slightly affected by biomass burning. The effective carbon ratio (ECR) and inhalation dose (ID) related EC indicated that finer particles or UFPs and PM0.5-1 contributed more to human health and global warming.
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•UFPs were first evaluated in Batam, a small island nearby Singapore and Malaysia.•PMs in Batam Island were influenced by local and transboundary emission.•Vehicle emission was the primary source of UFPs in Batam.•OC2 and OC3 were the dominant fractions of TC.
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