Scientists have found that aerosols like black carbon and dust, which makes the Indo-Gangetic Plain one of the most polluted regions of the world, have led to increased incidents of high rainfall events in the foothills of the Himalayan Region.
- The Indo-Gangetic Plain is located South and upwind of the Himalayan foothills.
- The region is associated with high aerosol loading, much of which is black carbon and dust, and thus provides an opportunity for studying how aerosol affects extreme rainfall events, particularly when air mass is forced from a low elevation to a higher elevation as it moves over rising terrain technically called orographic forcing.
- Researchers showed that particulate emissions can alter the physical and dynamical properties of cloud systems and, in turn, amplify rainfall events over orographic regions downwind of highly polluted urban areas.
Sources of Aerosols
- The bulk of aerosols—about 90 percent by mass—have natural origins. The remaining 10 percent of aerosols are considered anthropogenic, or human-made, and they come from a variety of sources.
Anthropogenic Sources of Aerosols
- Fossil fuel combustion produces large amounts of sulfur dioxide, which reacts with water vapor and other gases in the atmosphere to create sulfate aerosols.
- Biomass burning, a common method of clearing land and consuming farm waste, yields smoke that’s comprised mainly of organic carbon and black carbon.
- Automobiles, incinerators, smelters, and power plants are prolific producers of sulfates, nitrates, black carbon, and other particles. Deforestation, overgrazing, drought, and excessive irrigation can alter the land surface, increasing the rate at which dust aerosols enter the atmosphere.
- Even indoors, cigarettes, cooking stoves, fireplaces, and candles are sources of aerosols.
(PIB and NASA)
