Air Pollution from Agriculture: Using Satellite Observations to Study Ammonia Emissions

Ammonia (NH₃) is one of the most common nitrogen gas species and pollutants present in the lower troposphere. Ammonia enters the atmosphere through volatilisation from soils through the usage of nitrogen-based fertilisers in agriculture [1]. Because of its short lifetime (up to a few hours) [2], ammonia is highly reactive and can react chemically with acids in the atmosphere to form fine particulate matter (PM_2.5), playing an important role in secondary aerosol formation [3]. Wet and dry deposition of ammonia on soils and water bodies has shown to be detrimental to ecosystem biodiversity as it leads to acidification of the environment [3]. Therefore, observations of ammonia are essential for establishing air quality and environmental regulations for agricultural practices.

By using combined satellite measurements from the Infrared Atmospheric Sounding Interferometer (IASI) and the Cross-track Infrared Sounder (CrIS) instruments, we aim to study trends and the diurnal cycle of ammonia on regional scales, particularly in areas subjected to intensive agricultural activity, such as the Indo-Gangetic Plain (northern India). This research makes use of an optimal estimation-based method of monitoring ammonia with satellites called the University of Leicester IASI retrieval Scheme (ULIRS).

References:

[1] Van Damme M. et al (2021), Environ. Res. Lett., 16 055017

[2] Dammers E. et al (2019), Atmos. Chem. Phys., 12261–12293

[3] Erisman, J. W. et al (2007), Environ. Pollut., 150, 140– 149