Tiny solid and liquid particles suspended in the atmosphere are called aerosols. Examples of aerosols include windblown dust, sea salts, volcanic ash, smoke from fires, and pollution from factories. These particles block sunlight, hence can be measured with a parameter called Aerosol optical depth. AOD is a seasonal parameter that changes according to the level of water vapour and dust in the atmosphere, however the level of AOD can significantly increase when there are pollutants in the air.
Because of industrial and human activities the AOD levels are pretty high in the four major cities in India. However because of lockdown, there are some drastic lows in AOD hence proving the fact that the air around us has become much less polluted.
To analyse this situation, 550nm MODIS Terra AOD(8 days) was taken into account for cities Delhi, Mumbai , Chennai and kolkata for years 2017,2018,2019 and 2020 in the month of march and april and the graph hence plotted showed the drastic decrease in the level of AOD.
The value of AOD is measured between 0-1, where 0 depicts a clear atmosphere while 1 depicts the most polluted air.
Please select any city for the visual graphs
