Lockdown decreases aerosol concentration in atmosphere: VNIT researchers
| Date :05-May-2020 |
Staff Reporter :
A breakthrough research by a team of two researchers led by Prof Dr Y B Katpatal from Visvesvaraya National Institute of Technology (VNIT) has found that the ‘concentration and depth of aerosols in the atmosphere across India has significantly decreased’ during lockdown. Dr Yashwant B Katpatal, Professor, Department of Civil Engineering, VNIT-Nagpur and his M.Tech. (Environmental Engineering) students namely Vikas Patel and Prakash Taksal have conducted the study and concluded that the concentration and depth of aerosols in the atmosphere over pan-India significantly decreased during lockdown period. Using satellite data obtained from NASA, and spatial modelling, Dr Katpatal and his team have shown that during March 25 to April 25 in 2016-19, aerosol concentration was very high as compared to the same period in 2020.
Vikas Patel along with Prakash Taksal working under the guidance of Prof Dr Yashwant Katpatal measured Aerosol Optical Depth (AOD) and Aerosol Index (AI) using data from NASA for three Earth Observation Satellites (EOS) during March 25 to April 25. Lockdown 1.0 in the wake of COVID-19 was imposed in country from the night of March 24, 2020. Lockdown 2.0 was in effect till May 3, and presently Lock-down 3.0 is in force till May 17. VNIT researchers’ study estimated AOD for the years 2016 to 2019 and generated average of these years for India.
This average image was then compared with AOD estimated for the lockdown period during March 25 to April 25 this year (2020). The study shows a significant difference. The images show decreased AOD especially in Rajasthan, North, East, South, and Central India. Less difference is observed in the western parts. Similarly, AI is another measure of aerosol concentration. It also is seen reduced significantly pan-India especially in North and Central India, Dr Katpatal told ‘The Hitavada’. Dr Katpatal said that the difference in AOD values was relatively lower because the concentration of natural aerosol might not have varied drastically as those were governed by global climatic cycles. But, there was significant decrease in concentration of man-made aerosols, he said.
According to him, the study can help the authorities concerned in planning industrial and other activities in future through continuous reference to such indices. These indices can be generated regularly for different seasons, to monitor the impact of human activities on pollution, he added. The research by Dr Katpatal and team has estimated phase-wise aerosol levels in India. The study has also estimated aerosol concentrations in the context of global climate change.
The study indicates that if human activity is less, it directly affects the aerosol concentrations, which are directly related to pollution and climate. The study has been communicated to Elsevier publication’s International journal ‘Atmospheric Pollution Research’. As far as aerosols are concerned, they tiny droplets, dust particles, bits of fine black carbon, and other gases and pollutants present in the atmosphere. These affect climate and pollution levels. Aerosols can be natural or man-made. Natural aerosols include fog, geyser steam, volcanic dust etc while man-made aerosols include haze, dust, particulate air pollutants and smoke etc. The aerosol concentration is measured by estimating the AOD using satellite sensors. AOD is less when its concentration is less in the atmosphere. It is more when the concentration of particles is more. AI is more closely related to air pollution.