Aerosols and its impact on Climate
What are Aerosols?
Aerosols are fine solid particles or liquid droplets suspended in air or gas. They are ubiquitous specks of matter and they can be found in the air over oceans, deserts, mountains, forests, ice, and every ecosystem in between.
Major aerosol groups include sulfates, organic carbon, black carbon, nitrates, mineral dust, and sea salt. However, aerosols are often clump together to form complex mixtures.
Aerosols can be natural or anthropogenic:
- Natural aerosols are fog, dust, forest exudates and geyser steam.
- Anthropogenic aerosols are haze, particulate air pollutants and smoke. Anthropogenic aerosols create more damage to climate than natural aerosols.
Meteorologists typically call Aerosols as particulate matter—PM2.5 or PM10, depending on their size.
What are the sources of Aerosols?
- Fossil fuel combustion produces large amounts of sulfur dioxide, which reacts with water vapour and other gases in the atmosphere to create sulfate aerosols.
- Biomass burning, including stubble burning (in Punjab, Haryana and UP), yields smoke that contains mainly of organic carbon and black carbon.
- Automobiles, incinerators, smelters, and power plants
- Indoor smoke from cooking stoves, fireplaces, candles and cigarettes
- Deforestation, overgrazing, drought, and excessive irrigation increases the rate at which dust aerosols enter the atmosphere.
- Even strong winds of the “roaring forties” latitudes create a heavy band of airborne salt north of Antarctica.
- Dust plumes from Desert regions.
What is the impact of Aerosols on Climate?
- Their size range from a few nanometers—less than the width of the smallest viruses—to several tens of micrometres—about the diameter of human hair. Though they are tiny in size, they impact on our climate and our health significantly.
- Aerosols play a vital role in climate forcing, which affects climate and cloud formation system. There are two kinds of forcings.
- Positive forcings, such as excess greenhouse gases warm the earth
- Negative forcings, such as the effects of most aerosols and volcanic eruptions, actually cool the earth.
- Aerosols like black carbon accelerate melting of mountain glaciers by depositing a layer of dark residue on ice.
- Aerosols from wildfires and industrial pollution also hasten the melting of ice.
- It is found that aerosols from stubble burning in Punjab, Haryana and UP accelerated Delhi Air pollution during winter.
What are the steps taken by the government to tackle Aerosols?
- Project Surya to reduce black carbon in the atmosphere by introducing efficient cooking stove technologies, solar cookers, solar lamps and biogas plants.
- COALESCE (Carbonaceous Aerosol Emissions, Source Apportionment and Climate Impacts) project was launched on 7 July 2017. This aims to build an integrated aerosol, air pollution, and climate research community in the South Asian geographical domain.
- FAME (Faster Adoption and Manufacturing of Hybrid and Electric vehicles) Scheme.
- India has also flagged off Methanol Economy, which has the potential to reduce anthropogenic and natural aerosols.
India has taken various measures to curb the effects of Aerosols, however, attempts must be accelerated till the effects are controlled effectively.