National Ambient Air Quality Standards (NAAQS) are standards for air quality that are set by the
Central Pollution Control Board (CPCB) that are applicable all over the country.
The compliance of the NAAQS is monitored under the National Air Quality Monitoring
Programme (NAMP) implemented by the CPCB. The current standards (2009) comprise 12
pollutants as follows:
- Particulate Matter 10 (PM10): It is a type of particulate matter that is 10 micrometers
(μm) or less in diameter. PM is a mixture of solid particles and liquid droplets in the air.
PM10 can be made up of dust, salt, metals, and soot. - Particulate Matter 2.5 (PM2.5): It is a type of particulate matter that is 2.5 micrometers
or less in diameter. PM is a mixture of solid particles and liquid droplets in the air. PM10
can be made up of dust, salt, metals, and soot. - Nitrogen Dioxide (NO2): NO2 is produced by the burning of fuels in vehicles, power
plants, and off-road equipment. NO2 can irritate the lungs, increase the risk of
respiratory infections, and worsen asthma. It can also cause chronic lung disease, affect
the senses, and harm the heart. - Sulphur Dioxide (SO2): SO2 is emitted by power plants, commercial and institutional
boilers, internal combustion engines, manufacturing, and Industrial processes such as
petroleum refining and metal processing. SO2 can irritate the respiratory system,
causing coughing, wheezing, phlegm, and asthma attacks. It can also worsen existing
heart disease and asthma attacks, especially during physical activity. - Carbon Monoxide (CO): Carbon Monoxide is generated from vehicle exhaust, industrial
emissions such as steel mills, thermal power plants and forest fires. Carbon monoxide
(CO) can have significant negative effects on respiratory health. When inhaled, CO binds
to hemoglobin in the blood, reducing its ability to carry oxygen. - Ozone (O3): Ozone is a secondary pollutant, meaning it’s not directly emitted into the air
but forms through chemical reactions involving other pollutants. The primary sources of
these precursor pollutants are vehicular and industrial emissions. It can have significant
negative impacts on human health, especially for vulnerable populations like children,
the elderly, and individuals with respiratory conditions. - Ammonia (NH3): Ammonia, while naturally occurring, can also be a significant air
pollutant. The primary sources of ammonia emissions are fertilizer application in
agriculture, livestock farming and industrial emissions. Increased levels of Ammonia
cause respiratory problems, eye and skin irritation, neurological effects. - Lead (Pb): Lead is a naturally occurring element, but human activities have significantly
increased its presence in the environment. The primary sources of lead pollution are
burning of fossil fuels, battery manufacturing, certain types of ceramic, pottery, cosmetics
and medicines. Lead is highly toxic and can cause serious health problems, particularly
in children like neurological damage, anemia and kidney damage. - Benzene
- Benzopyrene
- Arsenic
- Nickel
Benzene, Benzopyrene, Arsenic and nickel are known carcinogens and can be harmful to
human health. The primary sources of these pollutants are industrial emissions from petroleum
and chemical industries, mining, smelting, coal combustion. Increased exposure health risks
include blood disorders, cancer and reproductive problems.
Difference between NAAQS and AQI:
The National Air Quality Index (AQI) was launched in 2014 to measure the air quality and rate it
in six categories (ranging from good to severe):
| AQI | Category |
| 0 – 50 | Good |
| 51 – 100 | Satisfactory |
| 101 – 200 | Moderate |
| 201 – 300 | Poor |
| 301 – 400 | Very Poor |
| 401 – 500 | Severe |
The NAAQS is more technical in nature. The AQI was launched keeping in mind the idea of
‘One Number-One Colour-One Description’. Another difference between both standards is that
while the NAAQS 2009 considers 12 pollutants, the AQI covers 8 major pollutants.
AQI includes all the NAAQS pollutants except benzene, benzopyrene, arsenic and nickel.
The measurement of air quality for AQI is based on the eight pollutants for which short-term (up
to 24-hourly averaging period) National Ambient Air Quality Standards are prescribed and the
worst reading in these pollutants represents the AQI for that region.