In India, The Central Pollution Control Board along with State Pollution Control Boards has been operating National Air Monitoring Program (NAMP) covering 240 cities of the country having more than 342 monitoring stations. In addition, continuous monitoring systems that provide data on near real-time basis are also installed in a few cities. They provide information on air quality in public domain in simple linguistic terms that is easily understood by a common person. Air Quality Index (AQI) is one such tool for effective dissemination of air quality information to people.
There are six AQI categories, namely Good, Satisfactory, Moderately polluted, Poor, Very Poor, and Severe. The proposed AQI will consider eight pollutants (PM10, PM2.5, NO2, SO2, CO, O3, NH3, and Pb) for which short-term (up to 24-hourly averaging period) National Ambient Air Quality Standards are prescribed. Based on the measured ambient concentrations, corresponding standards and likely health impact, a sub-index is calculated for each of these pollutants. The worst sub-index reflects overall AQI. The AQI values and corresponding ambient concentrations (health breakpoints) as well as associated likely health impacts for the identified eight pollutants are as follows:
AQI Category, Pollutants and Health Breakpoints
AQI Category (Range)
Moderately polluted (101-200)
Very poor (301-400)
Associated Health Impacts
May cause minor breathing discomfort to sensitive people.
Moderately polluted (101–200)
May cause breathing discomfort to people with lung disease such as asthma, and discomfort to people with heart disease, children and older adults.
May cause breathing discomfort to people on prolonged exposure, and discomfort to people with heart disease.
Very poor (301-400)
May cause respiratory illness to the people on prolonged exposure. Effect may be more pronounced in people with lung and heart diseases.
May cause respiratory impact even on healthy people, and serious health impacts on people with lung/heart disease. The health impacts may be experienced even during light physical activity.