Prelims: Current events of national and international importance| Environment
Why in News?
Researchers from Aryabhatta Research Institute of Observational Sciences (ARIES), spent a year (2022–2023) measuring non-methane hydrocarbons (NMHCs) in Munsyari, a high-altitude Himalayan tourist destination.
- NMHC – They are a highly reactive group of volatile organic compounds (VOCs) that contain only carbon and hydrogen, with methane explicitly excluded.
- Primary sources – They are primarily emitted by fossil fuel combustion, vehicular exhaust, industrial processes, and biomass burning.
- Gases included – Common atmospheric gases like ethane, ethene, propane, and benzene.
- Concentration variability – Parts per billion in remote areas to much higher levels in dense, industrialized, or urban locations.
Volatile Organic Compounds (VOCs) are carbon-based chemicals that easily vaporize into the air at room temperature.
Impacts
- Ozone Precursors – In the presence of sunlight and nitrogen oxides, NMHCs undergo complex photochemical reactions that form ground-level (tropospheric) ozone and harmful secondary pollutants like photochemical smog.
- Health Risks – While many light alkanes act largely as irritants or ozone precursors, heavier aromatic hydrocarbons such as benzene are highly toxic and well-documented carcinogens.
- Climate Influence – By reacting with atmospheric radicals (like hydroxyl radicals), NMHCs directly influence the lifetime of other greenhouse gases.
Reference
PIB| NMHC
