Assessment of biomass-burning types and transport over Thailand and the associated health risks

Biomass-burning (BB) related air pollution is a prime concern in several regions of the world including Southeast Asia. This study aimed to identify and apportion the BB types (agricultural, forest, and grassland) and assess the transport of BB-derived PM2.5 which influences the air quality index (AQI) of three major regions (i.e., central, north, and northeast) in Thailand by integrating satellite fire products, air-mass trajectories, ground-based measurements, statistical approaches, and modeling tools. We accounted for the transport time of PM2.5 from source to monitoring stations by grouping the BB type with air-mass trajectory timestamps. Forest fire predominated over the north (73%) and northeast (48%) whereas agricultural burning predominated over the central (52%) region. Grassland burning was most influential in the central region (16%) followed by the northeast (11%) and north (5%) regions in Thailand. Annual PM2.5 exposure amounted to very-unhealthy to hazardous PM2.5-AQI levels for about 79% of the Thailand population. PM2.5-AQI levels over Thailand were mainly governed by transboundary BB influence (67%) whereas the local contribution was about 33%. Excess numbers of premature deaths due to PM2.5 exposure totaled 18,003, and were associated with stroke burden (53%), ischemic heart disease (30%), lung cancer (12%), and chronic obstructive pulmonary disease (5%), based on public-health data from 2016. The spatial distribution results of excess mortality showed the largest burden in the central region (44%) followed by the northeast (29%), north (18%), and south (9%). Our study results are useful for shaping effective control strategies of open burning management in Thailand and other nearby countries in peninsular Southeast Asia.

Automated summary

According to the study, different regions in Thailand are affected by different types of BB, leading to varying levels of PM2.5 pollution, with forest fires being the main source of pollution. Analysis of PM2.5 exposure shows that around 79% of the population in Thailand is affected by very unhealthy and hazardous PM2.5-AQI levels.