Start wearing a N95 face mask when walking in Bangkok, the air pollutant PM2.5 is at unhealthy levels. 34 areas in the city and in surrounding provinces have levels of PM2.5 exceeding the safety standard, according to an air quality report by the Department of Pollution Control.
The air pollutant PM2.5 is fine particulate matter less than 2.5 micrometers in diameter. At high levels, the pollutant can be harmful to people’s health. Due to its small size, PM2.5 can get deep into the respiratory tract and lungs. It can also potentially enter the bloodstream.