PM2.5 pollution in different areas is the outcome of several factors. In Bangkok districts with traffic congestion, the main cause of PM2.5 is automobile exhaust, accounting for more than 65 percent of all PM2.5. KResearch projects that daily PM2.5 emissions from passenger cars and pickup trucks in Bangkok may reach at least 6 billion milligrams.
The major solution to address the PM2.5 problem in Bangkok should be management of exhaust emissions, especially from the 1.45 million old vehicles. Most of them are cars with diesel engines which have higher PM2.5 emission levels compared to other types of vehicles. Focus should be on direct actions related to car usage, along with other solutions, such as adoption of the Euro 5 emission standards set for 2024, support for reduced costs of vehicle inspection, improvement of traffic system, etc.
Meanwhile, promotion of the shift to battery electric vehicles (BEVs) is a long-term measure. This is because it may take until 2030 for Bangkok to see an increase in BEV passenger cars and pickup trucks to 10 percent of all registered vehicles, from around 0.6 percent in 2023.