Establishment of a City-Based Index to Communicate Air Pollution-Related Health Risks to the Public in Bangkok, Thailand

An Air Quality Health Index (AQHI), a health risk-based air pollution index, was constructed to communicate to the public their health risks due to exposure to air pollution in Bangkok, Thailand. This AQHI was built by analyzing the association between total excess respiratory disease-related deaths and individual air pollutants, using a time-series analysis of daily data from 2010 to 2019. We used Poisson regression in a generalized additive model, with natural cubic smooth splines to analyze the data and controls for other common variables (time, temperature, relative humidity, day of the week, and public holidays). The regression coefficients of these variables were then employed to establish the suitability of this AQHI for Bangkok. The results indicated that a 10-unit increase in particulate matter (PM10), fine particulate matter (PM2.5), ozone (O3), or nitrogen dioxide (NO2) was statistically associated with increased respiratory disease mortality. The coefficients of these four pollutants were then adopted in the construction of an AQHI for Bangkok. Compared with the currently used Air Quality Index (AQI), the AQHI was a more effective indicator in communicating multiple air pollution-related health risks to the public in Bangkok.