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News: CREA study says that secondary pollutants constitute up to third of PM2.5 pollution in the country.
About Secondary Pollutants
- Secondary pollutants are air pollutants that are not emitted directly from a source (such as vehicles or factories) but are formed in the atmosphere through chemical reactions involving primary pollutants and other atmospheric components like sunlight, oxygen, and water vapor.
- Their formation often makes them harder to control, as they can arise from various combinations of precursors and environmental conditions.
- Examples of secondary pollutants
- Tropospheric Ozone (O₃)
- Sulfuric acid and Nitric acid (component of acid rain)
- Peroxyacetyl Nitrate (PAN)
- Particulate Matter (PM)
- Photochemical Smog
- As per a study from the Centre for Research on Energy and Clean Air (CREA), Secondary pollutants, particularly ammonium sulphate, are responsible for nearly one-third of India’s fine particulate matter (PM2.5) pollution.
- Ammonium sulphate results from the reaction between sulphur dioxide (SO2) and ammonia (NH3) in the atmosphere,
- The main driver of ammonium sulphate formation and more than 60% of SO2 emissions in India originate from coal-fired thermal power plants.
- This makes them a critical target for reducing secondary PM2.5 pollution through the implementation of flue gas desulphurisation (FGD) systems.
