Health dept launches official air quality index

The Department of Health launched its official air quality index yesterday in order to give accurate risk readings for residents of Bangkok and its surrounding area, who have been affected by the increasing concentration of micro pollutants in the atmosphere in recent weeks.

The Air Quality Index (AQI) will be used as a benchmark to determine the kind of official warning that would be issued for the public, said the director-general of the Department of Health, Panpimol Wipulakorn.

The index contains five colour-coded warnings that range from "very good" to "very unhealthy". Each warning is determined by the atmospheric concentration of PM2.5 -- micro pollutants so miniscule they can enter the bloodstream through the lungs and cause cardiovascular disease.

A blue warning indicates "very good" air quality, with PM2.5 concentrations of less than 25 microgrammes per cubic metre (µg/m³). A green warning indicates a "good" PM2.5 reading of between 26-38 µg/m³, while a yellow, or "moderate" warning, reflects a PM2.5 reading of 38-50 µg/m³.

An orange warning indicates air quality that is "unhealthy for sensitive groups", with PM2.5 concentrations of between 51-90 µg/m³, while a red warning reflects "very unhealthy" conditions, with PM2.5 readings of above 91 51-90 µg/m³.

An orange warning have been issued for Bangkok and its immediate vicinity, as the concentration of PM2.5 exceeded the acceptable standard of 50 µg/m³ for three consecutive days.