Environmental impacts and costs of ozone formation in Bangkok Metropolitan Region

Ozone formation is an important environmental factor causing impacts on human health and ecosystem. Previous research relating to ozone formation often had limited scopes on direct emissions or focused on limited sectors of cities. This study aimed to quantify environmental impacts and costs due to ozone formation caused by energy generation, industry, agriculture, residential and commercial sectors, transport, fugitive gas emissions and waste treatment in the Bangkok Metropolitan Region (BMR) in 2022. The assessment applied spatially differentiated life cycle assessment framework, quantifying impacts on human health and ecosystem using local and global factors for on-site and supply chain emissions. The baseline situation in 2022 revealed that total emissions (on-site and supply chain) were 3.97E+05 tonnes of NOx and 1.15E+05 tonnes of NMVOC. NOx and the transport sector were the main stressor and hotspot causing impacts and costs of ozone formation in BMR. Total impact scores (on-site and supply chain) were 4.39E+02 disability-adjusted life year (human health impact) and 3.50E+01 species.year (ecosystem damage). The impacts were mainly contributed by on-site activities in BMR costing 6 billion Thai Baht. Scenarios were developed focusing primarily on the on-road transport since it was the hotspot causing health impacts and ecosystem damage. The scenarios indicated that upgrading fuel technology from diesel to compressed natural gas and modification of vehicles from diesel to electric were found to be very effective for overall reduction by more than 50% on average for health impacts and by more than 40% on average for ecosystem damage.