Days with high aerosol loading increasing

Central India has showed an increase in number of polluted days during winter season in recent years drawing attention to the rapid deteriorating air quality and also underlines the significance of increasing biomass burning, according to a study taken up by the University of Hyderabad (UoH).

Authors used 15 years of satellite and model re-analysis data sets over India and adjoining seas to examine trends in number of days with low to high aerosol loading during winter season. They found that the days with high aerosol loading (i.e. hazy days) are increasing at a rate of 2.6 days per year over central India.

Surprisingly, this increase of haze days over central India is higher than the change over Indo-Gangetic Plain (1.7 days annually). This rise in the number of hazy days over central India is associated with the relatively higher increase in biomass burning over the region. This results in a two-fold increase in atmospheric warming over central India as compared to the Indo-Gangetic plain, they said.

Dr Vijay Kanawade along with his PhD. student Abin Thomas from Centre for Earth, Ocean, and Atmospheric Sciences (CEOAS), UoH and Dr. Chandan Sarangi from Pacific Northwest National Laboratory, USA published an article on “Recent Increase in Winter Hazy Days over Central India and the Arabian Sea” available online in Scientific Reports at ‘Natureresearch journal’ of Nov 22.

The researchers used satellite and re-analysis data sets from 2003-2017 and investigated the trend in the number of hazy days (i.e. days with high aerosol loading) and the aerosol-induced direct radiation feedbacks on the surface-atmosphere system over India and adjoining seas for the dry winter season (November–February).

Although high aerosol loading is observed over the Indo-Gangetic plain than other regions, the study reveals that aerosol loading over central India has escalated greatly in recent years, especially between 2013–2017. The rate of change in the aerosol loading between past and recent years is distinctive regionally due to the variability in aerosol emission rates and latitudinal diverse climatic conditions, the study added.

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