Main air pollutants in Sri Lanka include ground-level ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide and particle pollution. In order to protect the health of the general public from each of these pollutants, National Ambient Air Quality Standards, regulation have been gazzetted under the National Environmental Act in 1994.
It is essential for the country to have simple air quality information tool, for the general public. With this objective of Sri Lanka Air Quality Index, or SLAQI, was developed. It works as a yardstick that rang from 0 to 300. Lower the index is, better the quality and higher the SLAQI value, the greater the level of air pollution and the health concerns. For example, an SLAQI value of 50 represents good air quality with little potential to affect public health, while an SLAQI value over 300 represents hazardous air quality. A SLAQI value of 100 corresponds to the national air quality standard for the specific pollutant, below which are considered as satisfactory. For easy understanding a specific color is assigned to each SLAQI category, which demonstrates whether air pollution is reaching unhealthy levels.
For example, color pink indicates air quality is unhealthy for sensitive groups, while red is unhealthy for everyone. The SLAQI designed to be used countrywide, to provide general public with air quality information and the health concerns attributed to different levels of air pollution and to indicate how one can protect health when our pollutants reach unhealthy levels.