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Black Carbon

Posted on June 8, 2021 by admin1  452

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Accurate estimation of black carbon (BC), the second most important global warming pollutant after CO­2, will now be possible using optical instruments in the Himalayan region.

Observations

  • Scientists have estimated it with the help of a parameter called the mass absorption cross-section (MAC) specific to the Himalayan region.
  • MAC is an essential parameter which is used for obtaining Black Carbon mass concentrations. 
  • Scientists at the Aryabhatta Research Institute of Observational Sciences (ARIES), in collaboration with scientists from the University of Delhi, IIT Kanpur and Space Physics Laboratory, ISRO have made extensive observations of black carbon and elemental carbon and estimated monthly and wavelength-dependent values of MAC over the central Himalayan region for the first time.
  • The study revealed that these estimated MAC values show significant seasonal variation. It is found that these changes are caused by the seasonal variability of biomass burning, air mass variation, and meteorological parameters.

 

Significance of Observations

  • These higher resolution multi-wavelength and long-term observations used in calculating MAC will help improve the performance of numerical weather prediction and climate models in estimating the warming effects caused by BC emissions. 
  • The precise knowledge on BC at various wavelengths will help in source apportionment studies done to constrain the sources of BC emissions. 
  • Thus, this can serve as important information to form the mitigation policies.

 

Black Carbon (BC)

  • Black carbon, or soot, is part of fine particulate air pollution (PM2.5).
  • It is formed by the incomplete combustion of fossil fuels, wood and other fuels. 
  • The complex mixture of particulate matter resulting from incomplete combustion is often referred to as soot.
  • The combustion is never complete and CO2, carbon monoxide, volatile organic compounds, and organic carbon and black carbon particles are all formed in the process. 
  • Black carbon is a short-lived climate pollutant with a lifetime of only days to weeks after release in the atmosphere. 
  • India is the second largest emitter of black carbon in the world, with emissions expected to increase dramatically in the coming decades.

 

Impacts of Black Carbon

  • Climate Impacts
    • Black carbon is an important contributor to warming because it is very effective at absorbing light and heating its surroundings. E.g. Per unit of mass, black carbon has a warming impact on climate that is 460-1,500 times stronger than CO2.
    • When suspended in the atmosphere, it contributes to warming by converting incoming solar radiation to heat. 
    • It also influences cloud formation and impacts regional circulation and rainfall patterns.
    • When deposited on ice and snow, black carbon and co-emitted particles reduce surface albedo (the ability to reflect sunlight) and heat the surface. The Arctic and glaciated regions such as the Himalayas are particularly vulnerable to melting as a result.
  • Health Impacts
    • Black carbon and its co-pollutants are key components of fine particulate matter (PM2.5) air pollution, the leading environmental cause of poor health and premature deaths.
    • PM2.5 has been linked to a number of health impacts including premature death in adults with heart and lung disease, strokes, heart attacks, chronic respiratory disease such as bronchitis, aggravated asthma and other cardio-respiratory symptoms. 
    • Each year, an estimated 7 million premature deaths are attributed to household and ambient (outdoor) PM2.5 air pollution.
  • Impacts on Vegetation and Ecosystems
    • Black carbon can affect the health of ecosystems in several ways: by depositing on plant leaves and increasing their temperature, dimming sunlight that reaches the earth, and modifying rainfall patterns.
    • Changing rain patterns can have far-reaching consequences for both ecosystems and human livelihoods.

 

                                                                                                                       

 

(Image Courtesy: www.ccacoalition.org )

 

Solutions

Adopting the following measures would have major positive co-benefits for public health, especially in the developing world.

 

Household Energy
  • Replace traditional cooking to clean burning modern fuel cookstoves and clean-burning biomass stoves
  • Eliminate kerosene lamps
  • Replace lump coal with coal briquettes for cooking and heating

Industrial Production
  • Modernize traditional brick kilns to vertical shaft brick kilns
  • Modernize coke ovens to recovery ovens

Transport
  • Use diesel particulate filters for road and off-road vehicles
  • Fast transition to Euro VI/6 vehicles and soot-free buses and trucks
  • Eliminate high-emitting diesel vehicles

Agriculture
  • Ban open-field burning of agricultural waste

Fossil Fuels
  • Capture and improve oil flaring and gas production

Waste Management
  • Ban open burning of municipal waste

 

Conclusion

  • The measures to prevent black carbon emissions can reduce near-term warming of the climate, increase crop yields and prevent premature deaths.
  • Black carbon’s short atmospheric lifetime, combined with its strong warming potential, means that targeted strategies to reduce emissions can provide climate and health benefits within a relatively short period of time.

Glaciers of the Himalayas : Climate Change, Black Carbon, and Regional Resilience

  • It is a research report published by the World Bank.
  • The 55,000 glaciers in the Himalaya, Karakoram, and Hindu Kush (HKHK) mountain ranges store more freshwater than any region outside of the North and South Poles. 
  • Their ice reserves feed into three major river basins in South Asia—the Indus, Ganges, and Brahmaputra—that are home to 750 million people. 
  • Melting glaciers and the loss of seasonal snow pose significant risks to the stability of water resources in South Asia. 
  • Reasons for melting:
    • One major regional driver of the accelerating glacier melt is climate change, which is altering the patterns of temperature and precipitation. 
    • A second driver may be deposits of anthropogenic black carbon (BC), which increase the glaciers’ absorption of solar radiation and raise air temperatures. Recent evidence suggests that it is responsible for more than 50 percent of the accelerating glacier and snow melt.
  • Impacts of melting:
    • The changes in water supply caused by melting glaciers affect agriculture and human consumption of water. In the long run, decreased water availability would aggravate water shortage.
    • The glacier melt contributes to disasters such as flash floods, landslides, soil erosion, and glacial lake outburst floods (GLOF), with mountain communities especially vulnerable to such disasters. 
    • The melting and thinning of glaciers may also affect hydropower production, which is a key source of renewable energy for the region. 
    • Potential damage to other sectors (infrastructure, hydropower, water supply) will also adversely affect the larger tourist industry. 
  • Suggestions to contain BC:
    • Managing water resources now is key to mitigating the potential impacts of glacier melt. 
    • Countries such as India need to manage their hydropower and storage resources carefully. 
    • Regional cooperation can be an effective transboundary solution, helping countries in the HKHK region to manage glaciers and related natural assets collaboratively.

 

Aryabhatta Research Institute of Observational Sciences (ARIES)

  • It is an autonomous institute under the Department of Science & Technology (DST), the Government of India.
  • The ARIES came into existence on 22nd March 2004.
  • ARIES has 32.38 hectares of land at Manora Peak, Nainital on which functional and residential buildings are located.
  • It specializes in observational Astronomy & Astrophysics and Atmospheric Sciences. 
    • Astronomy & Astrophysics Division: The main research interests are in solar, planetary, stellar, galactic and extragalactic astronomy including stellar variabilities, X-ray binaries, star clusters, nearby galaxies, quasars, and inherently transient events like supernovae and highly energetic Gamma Ray Bursts. 
    • Atmospheric Sciences division: Research focus is mainly in the lower part of the atmosphere and covers the studies on aerosols and trace gases. 
    • Relativistic Astrophysics: To strengthen the scientific contribution, the Institute has extended its horizon to theoretical and numerical studies in Relativistic Astrophysics. 
  • The unique position of ARIES (79° East), places it at almost in the middle of 180° wide longitude band, between Canary Island (20° West) and Eastern Australia (157° East), and therefore complements observations which might not be possible from either of these two places. 
  • The Institute hosts three telescopes of apertures 104-cm, 130-cm and 3.6-mDOT. 
  • There are different instruments for observation of physical and optical properties of aerosols and trace gas. 
  • An 84-cm micro-pulse LIDAR system for high altitude studies of aerosols and a ST Radar (Stratosphere Troposphere Radar) to measure winds speed up to an altitude of around 20 km is also being set up.
  • The Scientists from the Solar group of ARIES are also participating in the national projects like space coronagraph and National Large Solar Telescope (NLST). 

Light Detection and Ranging (LIDAR)

  • LIDAR is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth. 
  • These light pulses, combined with other data recorded by the airborne system, generate precise, three-dimensional information about the shape of the Earth and its surface characteristics.

National Large Solar Telescope (NLST) 

  • It is a proposed ground based 2-m class optical and near infra-red (IR) observational facility in the country. 
  • It is designed to address an array of key scientific issues related to origin and dynamics of solar magnetic fields at a spatial resolution of 0.1-0.3 arc-second. 
  • The instrument has a broad scope to support and substantiate the multitude of solar atmospheric observations from space-based ADITYA mission and ground based MAST telescope (Udaipur).

Multi Application Solar Telescope (MAST) 

  • It is a telescope for the detailed study of the Solar activity including its magnetic field, has been operationalised at the Udaipur Solar Observatory (USO) of Physical Research Laboratory (PRL).
  • MAST is an off-axis Gregorian-Coude telescope with a 50 cm aperture.
  • The USO is situated on an island in the middle of the Lake Fatehsagar of Udaipur, Rajasthan, India.
  • The sky conditions at Udaipur are quite favourable for solar observations. 
  • The main objective of obtaining the high spatial and temporal resolution observations of solar photospheric and chromospheric activity is to understand the various dynamic phenomena occurring on the surface of the Sun.

Physical Research Laboratory (PRL)

  • It is an autonomous unit of the Department of Space. 
  • PRL is a premier research institute engaged in basic research in the areas of Astronomy and Astrophysics, Solar Physics, Planetary Science and Exploration, Space and Atmospheric Sciences, Geosciences and Theoretical Physics. 
  • Apart from the main campus at Ahmedabad, there are two other campuses at Mt. Abu and Udaipur, hosting the Infrared Telescope and a Multi-Application-Solar Telescope (MAST), respectively. 
  • The planetary exploration (PLANEX) programme and the astronomy group are housed in the fourth campus at Thaltej, close to Ahmedabad.
     

Sources: PIB

 

 
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