Air Quality Index
Context:
- The overall air quality in Delhi continued to remain in the ‘critical’ category on Monday morning, according to the System of Air Quality and Weather Forecasting and Research (SAFAR)-India.
- Pollution levels in Delhi have remained in the ‘critical’ category for the past few days recording AQI in the ‘400’ range at several locations in and around Delhi.
- According to data Data from the Central Pollution Control Board showed Delhi’s air quality index increased by over 200 points since October 27.
About AQI:
- AQI is envisioned as the ‘One Number- One Colour-One Description’ for the common man to judge the air quality within his vicinity.
- The formulation of the index was a continuation of the initiatives under Swachh Bharat Mission envisioned by the Hon’ble Prime Minister Shri NarendraModi.
- While the earlier measuring index was limited to three indicators, the current measurement index had been made quite comprehensive by the addition of five additional parameters.
- Under the current measurement of air quality, 8 parameters. The initiatives undertaken by the Ministry recently aimed at balancing environment and conservation and development.
- Air pollution has been a matter of environmental and health concerns, particularly in urban areas.
- Central Pollution Control Board along with State Pollution Control Boards has been operating National Air Monitoring Program (NAMP) covering 240 cities of the country.
- In addition, continuous monitoring systems that provide data on near real-time basis are also installed in a few cities.
- There are six AQI categories, namely Good, Satisfactory, Moderately polluted, Poor, Very Poor, and Severe.
- The AQI will consider eight pollutants (PM10, PM5, 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.
- Associated likely health impacts for different AQI categories and pollutants have been also been suggested, with primary inputs from the medical expert members of the group.
- 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) | PM10
24-hr |
PM2.5
24-hr |
NO2
24-hr |
O3
8-hr |
CO
8-hr (mg/m3) |
SO2
24-hr |
NH3
24-hr |
Pb
24-hr |
| Good (0-50) | 0-50 | 0-30 | 0-40 | 0-50 | 0-1.0 | 0-40 | 0-200 | 0-0.5 |
| Satisfactory (51-100) | 51-100 | 31-60 | 41-80 | 51-100 | 1.1-2.0 | 41-80 | 201-400 | 0.5 –1.0 |
| Moderately polluted
(101-200) |
101-250 | 61-90 | 81-180 | 101-168 | 2.1- 10 | 81-380 | 401-800 | 1.1-2.0 |
| Poor
(201-300) |
251-350 | 91-120 | 181-280 | 169-208 | 10-17 | 381-800 | 801-1200 | 2.1-3.0 |
| Very poor
(301-400) |
351-430 | 121-250 | 281-400 | 209-748* | 17-34 | 801-1600 | 1200-1800 | 3.1-3.5 |
| Severe
(401-500) |
430 + | 250+ | 400+ | 748+* | 34+ | 1600+ | 1800+ | 3.5+ |
| AQI | Associated Health Impacts |
| Good
(0–50) |
Minimal Impact |
| Satisfactory
(51–100) |
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. |
| Poor
(201–300) |
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. |
| Severe
(401-500) |
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. |
Syllabus: Prelims
