Why in news?
Scientists from the Aryabhatta Research Institute of Observational Sciences (ARIES) measured non‑methane hydrocarbons (NMHCs) in the air at Munsyari in Uttarakhand between 2022 and 2023. Their findings showed that even the remote Himalayan environment is now affected by reactive gases, with higher levels in spring and autumn and lower levels in winter and during the monsoon. The study warns that long‑term exposure to these gases could harm human health and ecosystems in high‑altitude regions.
Background
NMHCs are volatile organic compounds made up of carbon and hydrogen. They are not methane, but they behave similarly in the atmosphere. These gases come mainly from human activities such as burning fuel, industrial processes, the use of solvents and road traffic. Major compounds include ethane, ethylene, propane, toluene, xylene and benzene. Benzene is a toxic aromatic hydrocarbon.
NMHCs are chemically reactive. In the presence of sunlight they react with nitrogen oxides to form ozone and aerosols. These reactions contribute to smog and can damage lung tissue. Because of their high reactivity, even small increases in NMHC levels can lead to a large increase in ground‑level ozone.
Key findings from the study
- Seasonal pattern: Concentrations were lowest in winter and the rainy season and highest in spring and autumn. This pattern indicates that emissions from household heating and crop burning may play a role.
- Sources of pollution: The study pointed to local sources such as cooking fuel (liquefied petroleum gas and diesel), vehicular traffic and construction activities. Air masses bringing emissions from the Indo‑Gangetic Plain also reached the site.
- Aromatic hydrocarbons: Compounds like benzene and xylene were found in significant quantities. They contribute strongly to the formation of ozone and are known to pose long‑term health risks.
- Remote areas no longer clean: The results show that even high‑altitude areas once considered pristine are now affected by pollution. Persistent monitoring and targeted clean‑up plans are needed to protect the Himalayan environment.
Conclusion
NMHCs may not be as familiar as methane, but they play a major role in air pollution and climate. The Munsyari study reveals how human activities are spreading reactive gases into remote mountain regions. Cutting vehicular emissions, promoting clean fuels and carefully managing construction in fragile areas are essential to safeguard Himalayan health.