Carbon and Trace Element Compositions of Total Suspended Particles (TSP) and Nanoparticles (PM0.1) in Ambient Air of Southern Thailand and Characterization of Their Sources

Abstract

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.

Atmospheric Ultrafine Particulate Matter (PM_0.1) Bound Carbon Composition in Bangkok, Thailand

“…[29] in Hsinchu, Taiwan (33.2 ± 6.5 µg/m 3 ). Nevertheless, the concentrations of PM0.1 were mainly more significant than those in large cities in Asian countries, e.g., Hat Yai (2018), Thailand (10.2 ± 2.2 µg/m 3 ) [23], Hat Yai (2019), Thailand (10.4 ± 1.2 µg/m 3 ) [12], Shanghai, China (13.4 µg/m 3 ) [30] and Hanoi, Vietnam (6.1 ± 2.7 µg/m 3 ) [4] (Table 1). The PM0.1 in this study was also higher than those in cleaner zones, for instance, in North Sumatra, Indonesia (7.1 µg/m 3 ) [13], 2.2 ± 0.6 µg/m 3 in the traffic area in Hsinchu, Taiwan [29], 1.4 ± 0.6 µg/m 3 in New Taipei, Taiwan [31] and 4.7 µg/m 3 in Kanazawa, Japan [32].…”

“…PM2.5 average concentration during the dry season was reported to be exceeding the 24-hr standard for Thailand (50 µg/m 3 ) and more significant than the World Health Organization (WHO) standards (10 µg/m 3 ). Moreover, transboundary particulate pollutant has been an increasing concern recently [6,12].…”

“…The Asian atmosphere is still limited in information on UFPs fraction, even though the Asian region has been the leading contributor to particulate pollution in the recent decade [14]. Several studies have deliberated the particulate pollution bound to the chemicals in several nations around Asia due to health effects and environmental damages [12,13,14]. Many studies are based on ground-based detecting, scientific modeling, and satellite image techniques [6,15,16,17].…”

“…Recent decades exposed that ambient PM plumes during haze episodes exceeded many countries' national standards, with an extreme value compared to WHO or other countries' standards [18]. Thailand and Southeast Asian (SEA) countries displayed that UFPs mass concentrations are around 15-20% of the total suspended particulate matter (TSP) in the ambient air [12,13,14,19].…”

“…Carbonaceous aerosols (CA) are typically separated into two broad classes based on their thermal-optical properties, and the total carbon (TC) is split into operationally defined elemental carbon (EC) and organic carbon (OC) [20]. Total carbon (TC) is the most composed of particles that occupy particle mass concentrations of approximately 20-50% [12,13]. The importance of PM in modifying the Earth's climate has been recognized for a long time [21].…”