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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.

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.

The objective of this study was to characterize ambient nanoparticles (PM0.1)-bound metals in Bangkok, Thailand and assess the health risks of these materials to human. A year-long sampling campaign was conducted between November 2014 and October 2015. The PM0.1 mass concentration ranged from 10 to 27 μg/m3, and the average PM0.1 mass concentration was 15 ± 2 μg/m3. The total concentration of the thirteen elements was 345 ± 31 ng/m3, with Fe, K, Na, Al, Cu, Mg, and Zn (>10 ng/m3) being the dominant species. The highest total element concentration occurred in the cold dry season followed by the hot dry and wet seasons. A principal component analysis (PCA) indicated that the primary sources of PM0.1 were derived from road traffic, the industrial sector, and biomass burning. The high concentrations of metals found in the cold dry season suggest that PM0.1-bound metal derived from road traffic and biomass burning from neighboring areas were transported to Bangkok. High level of K indicates that biomass burning was a major source during cold dry season. Total cancer risk from all the carcinogenic elements was 5.84 × 10−6 in adults, which does not exceed the upper limit of the acceptable risk assessment range. The findings of this study provide further clarification of the emission source profile and the pattern of PM0.1 particles and should be of value for emission control and mitigation of PM emission in an urban area.