Royal Thai Government: Urban Air Quality in Bangkok, Thailand

Executive Summary

Bangkok (BKK), the capital city of Thailand, has the largest population and population density in Thailand. Bangkok Metropolitan Region (BMR) refers to Bangkok and five adjacent provinces, including Nakhon Pathom, Pathum Thani, Nonthaburi, Samut Prakan, and Samut Sakhon. These five provinces are linked to BKK in terms of traffic and industrial development (Zhang and Oanh, 2002). Since 1995, BKK has experienced exceedances in Thailand National Ambient Air Quality Standard (NAAQs) for particulate matter (PM) and ozone (O3) (PCD, 2015). The transportation and industrial sectors are considered to be the major sources of air pollutants in BKK (Watcharavitoon et al., 2013). In this study, gaseous criteria pollutants and trends in BMR during 2010-2014 are investigated. O3 and its precursors (only NO and NO2) are analysed since they are the species that were measured at a majority of the monitoring sites. Interconversion between O3 and its precursors and photochemical reaction rate during photostationary state are examined. Local emission, regional contribution and possible emission sources of pollutants that associate with O3 formation are identified. Air quality models, including Weather Research and Forecasting (WRF) model and Community Multiscale Air Quality (CMAQ) model, will be applied, in order to gain more understanding of atmospheric pollution and pollution transport over BMR. Moreover, transport and emission from China and India will be considered in this study.