Air PollutionAir QualityOutdoor Air Quality

Air pollution is a major concern these days. The presence of an unwanted thing, contaminant, or agent in the air leads to air pollution. AQI is used to represent the quality of air present around us.

What is the Air Quality Index (AQI)? 

Air Quality Index (AQI) is a number used to convey the quality of air by the government to the general public. Air quality deteriorates with an increase in the concentration of pollutants. The Air Quality Index represents the severity of pollution for ordinary people.

Indian (CPCB) AQI:

According to the Indian Government (CPCB), Indian AQI range is from 0-500, from 0 being good and 500 being severe. There are eight major pollutants to be taken into account for AQI calculation, viz. particulate matter (PM 10 and PM 2.5), carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), ammonia (NH3), and lead (Pb). To calculate AQI, data for a minimum of three pollutants must be present, of which one should be either PM10 or PM2.5, AQI ranging from 0-500 has different concentrations for each pollutant and has health effects accordingly.

Indian AQI range & probable impacts:

0-50: This range defines air quality as good as it shows minimal or no impact on health.

51-100: This is a satisfactory air quality range and it can show effects such as breathing difficulty in sensitive groups.

101-200: The range shows moderate air quality with impacts such as breathing discomfort for children and elderly people, and people already suffering from lung disorders and heart disease.

201-300: AQI falling in this range communicates that the air quality is poor and shows health effects on people when exposed for the long term. People already suffering from heart diseases can experience discomfort from short exposure.

301-400: This range shows very poor air quality and causes respiratory illness for a longer duration of exposure.

401-500: This is the severe range of AQI causing health impacts to normal and diseased people. It also causes severe health impacts on sensitive groups.


The ranges of US AQI from 0-500 according to US-EPA, 0 stands for good and 500 for severe. The six major air pollutants are taken to calculate AQI, which are, Particulate Matter (PM 10 and PM 2.5), carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2). AQI ranging from 0-500 has different pollutant concentrations and associated health effects.

US-EPA AQI range & probable impacts:

0-50: The range shows that the air quality is good and it poses no health threat.

51-100: This range is moderate and the quality is acceptable. Some people may experience discomfort.

101-150: The air quality in this range is unhealthy for sensitive groups. They experience breathing discomfort.

151-200: The range shows unhealthy air quality and people start to experience effects such as breathing difficulty.

201-300: Air quality is very unhealthy in this range and health warnings may be issued for emergency conditions. All people are likely to be affected.

301-500: This is the hazardous category of air quality and serious health impacts such as breathing discomfort, suffocation, airway irritation, etc. may be experienced by all.

Air Quality Index Parameters

1. Particulate Matter (PM10 & PM2.5)

pm2.5 iconA mixture of particles with liquid droplets in the air forms particulate matter. PM 10 are particles that have a size of less than or equal to 10 microns whereas PM2.5 are ultra-fine particles having a size of less than or equal to 2.5 microns.


Particulate Matter is released from constructions, smoking, cleanings, renovations, demolitions, constructions, na