The government is looking to prepare a unified testing methodology to ensure that all agencies that map air pollution use accurate instruments
What has happened?
The Council of Scientific and Industrial Research (CSIR)-National Physical Laboratory (NPL) is in the process of setting up ‘gas standards’, or reference samples of,
- Carbon Monoxide (CO)
- Sulphur Dioxide (SO2)
- Nitrous Oxide (NO2)
- Particulates –Pb (lead), –As (Arsenic) and –Ni (Nickel)
Currently, the National Ambient Air Quality standards specify the upper limits for pollutants and, based on this, the Air Quality Index — that grades air quality in cities from ‘Good’ to ‘Severe’ — is prepared for several Indian cities.
The measurement devices are not calibrated properly and errors creep in
Talks with CPCB
There would be talks with environment-monitoring agencies like the the Central Pollution Control Board (CPCB) to see if these can become reference standards for use by all private and public agencies that measure pollution levels
What is Ambient Air Quality?
Ambient air quality refers to the condition or quality of air surrounding us in the outdoors
- National Ambient Air Quality Standards are the standards for ambient air quality set by the Central Pollution Control Board (CPCB) that is applicable nationwide
- The CPCB has been conferred this power by the Air (Prevention and Control of Pollution) Act, 1981
- The current National Ambient Air Quality Standards were notified on 18thNovember 2009 by the Central Pollution Control Board. It contains a list of 12 pollutants,
- Sulphur dioxide (S02)
- Nitrogen dioxide (NO2)
- Particulate matter having micron (PM10)
- Particulate matter having size less than 2.5 micron (PM2.5)
- Carbon monoxide (CO)
Prior to the November 2009 standards, India had set Air Quality standards on 11 April 1994, and this was later revised on 14 October 1998. The 2009 standards further lowered the maximum permissible limits for pollutants and made the standards uniform across the nation. Earlier, less stringent standards were prescribed for industrial zones as compared to residential areas
National Air Quality Index (NAQI)
A new National Air Quality Index (AQI) was launched in October 2014 to disseminate information on air quality in an easily understandable form for the general public. It was launched under Swachh Bharat.
- The measurement of air quality is based on eight pollutants, namely,
, for which short-term (up to 24-hourly averaging period) National Ambient Air Quality Standards are prescribed. It may be noted that ambient air quality standards are specified separately in India for around 12 pollutants including the 8 that constitute the Air Quality Index
- AQI has six categories of air quality. These are: Good, Satisfactory, Moderately Polluted, Poor, Very Poor and Severe
Who monitors the ambient air quality in India?
Central Pollution Control Board (CPCB) and State Pollution Control Boards (SPCBs)/Pollution Control Committees (PCCs) monitors the ambient air quality at 680 monitoring stations located in 300 cities/towns covering 29 states and 6 union territories across the country under National Air Quality Monitoring Programme (NAMP)
Objectives of NAMP
The objectives of the NAMP are,
- To determine status and trends of ambient air quality
- To ascertain whether the prescribed ambient air quality standards are violated
- To Identify Non-attainment Cities
- To obtain the knowledge and understanding necessary for developing preventive and corrective measures and to understand the natural cleansing process undergoing in the environment through pollution dilution, dispersion, wind based movement, dry deposition, precipitation and chemical transformation of pollutants generated
What the pollutants measured under NAMP
Under N.A.M.P., four air pollutants have been identified for monitoring at all locations,
- Sulphur Dioxide (SO2)
- Oxides of Nitrogen as NO2
- Suspended Particulate Matter (SPM)
- Respirable Suspended Particulate Matter (RSPM / PM10)
How has ambient air quality monitoring evolved in India?
Ambient Air Quality Monitoring- a chronology
- National Ambient Air Quality Monitoring (NAAQM) started by CPCB . Renamed as National Air Quality Monitoring Programme (NAMP). Only 7 stations at Agra and Anpara.
- Only 3 pollutants were monitored
1985- 28 stations
2012- 544 covering 224 cities in 26 states and 5 Union Territories as
1994- National Ambient Air Quality Standards on April 11, 1994
- Revised National Ambient Air Quality Standards (NAAQS) [NAAQS Notification dated 18th November, 2009]
- Specified Standards for 12 pollutants
- Instead of land-use classification , keeping in view health impact of air pollution the category of area affected was revised to include – 1. Industrial areas/residential areas and Ecologically sensitive areas
- Real-time monitoring also started from 2009 onwards.
- Ambient air quality index was released
- CPCB has recently expanded monitoring through continuous monitoring instruments that are capable of generating data on the real time basis for most of the pollutants like PM2.5, O3, CO etc regularly.
- CPCB has also started releasing daily health advisory based on real-time monitoring. On this basis CPCB is issuing the Air quality index for a few cities on a daily basis.
- The AQI is decided on ambient concentration values of air pollutants and their likely health impacts which are commonly called health break points.
- The pollution parameters whose concentration is measured in ambient air include particulate matter that are of size 2.5 microns (PM 2.5), PM 10, nitrogen dioxide, sulphur dioxide, carbon monoxide, ozone, ammonia and lead.
- The pollution parameter is measured over a period of 24 hours and the data is revealed by the CPCB the following day. This is used to give health advisory for the masses.