Ground-Level Ozone (Geography, Disaster Management)
Ground-Level Ozone (Geography, Disaster Management)
Why In News:
A new study finds that heatwaves are causing increased concentrations of ground-level ozone, which in turn aggravates respiratory and cardiovascular health risks.
Two Types of Ozone
Stratospheric Ozone (Good Ozone): Located 15-35 km above Earth. Absorbs harmful UV-B and UV-C radiation. Depletion caused by CFCs leads to the ozone hole, measured in Dobson Units. Protected by the Montreal Protocol, 1987.
Ground-Level (Tropospheric) Ozone (Bad Ozone): Found in the lowest atmospheric layer (troposphere, 0-12 km). NOT emitted directly. Forms through chemical reactions between pollutants in sunlight.
How Ground-Level Ozone Forms
Precursor Pollutants: Nitrogen oxides (NOx) and Volatile Organic Compounds (VOCs) from vehicles, industries, and power plants react with sunlight to produce ozone.
Heatwave Connection: High temperatures and intense sunlight accelerate photochemical reactions that form ozone. Heatwaves therefore directly increase ground-level ozone concentrations.
Climate Feedback: As global warming intensifies, heatwaves become more frequent and severe, worsening ground-level ozone episodes in a reinforcing cycle.
Key Facts for Prelims
National Air Quality Index (NAQI): India's AQI measures 8 pollutants including ozone, PM2.5, PM10, NO2, SO2, CO, NH3, and lead.
CPCB: Central Pollution Control Board monitors air quality including ground-level ozone under the Environment Protection Act, 1986.