Faculty of Engineering, Mahidol University led by Assoc. Prof. Dr. Trakarn Prapaspongsa from Department of Civil and Environmental Engineering, Faculty of Engineering, Mahidol University organized the brainstorming meeting entitled “Assessment of PM2.5 and Health Impact Reduction Options from Road Transport in Bangkok Metropolitan Region (BMR)” via Zoom meeting on 28 September 2021. This activity is a part of the project entitled “Awareness Raising and Policy Design for Reducing Health Impacts and Costs of Fine Particulate Matter Formation from Passenger Transport in Thailand” funded by the Policy Advocacy Project 2020, Mahidol University. The meeting aimed at presenting health impacts and costs of PM2.5 from Road Transport in BMR; brainstorming on recommendations on how to apply the PM2.5 reduction options in practice; and raising awareness on health risks from PM2.5 from road transport in BMR. In this event, there were 75 participants from Pollution Control Department (PCD), Department of Environmental Quality Promotion (DEQP), Department of Disease Control, Department of Health, Department of Land Transport, Department of Disaster Prevention and Mitigation, Office of Transport and Traffic Policy and Planning (OTP), Department of Environment, Bangkok Metropolitan Administration (BMA), Bangkok Mass Transit Authority (BMTA), associations and confederations on vehicles, transport and logistics, Center for Clean Air Solutions (CCAS), Thailand Network Center on Air Quality Management (TAQM) and universities. The results from this meeting will be a part of the policy recommendation report, which will be prepared and disseminated in the future.