Release of ammonia, particulate matter and nitrogen oxides during the Covid-19 quarantine: what is the role of livestock activities?

Several gases contribute to air pollution and most of all to the formation of secondary particulate matter (PM 2.5 ), which is recognized as a source of severe risk to human health. Even if huge steps forward have been done worldwide, traffic, industrial activities, and the energy sector are mostly responsible for the release of NOx and SOx, while the agricultural sector is mainly responsible for the emission of NH 3 deriving from the barn, the manure storage, management and final field application. In this study, the emission of PM 2.5 , NOx and NH 3 is analyzed in the main provinces of the Lombardy region in which livestock activities are carried out, comparing emissions of 2016-2019 and those of 2020 during the lockdown determined by the spread of Covid-19 disease. The aim is to understand if and how a change in air emissions can be identified. The results show that PM 2.5 and NOx reduced, most of all in urban areas, whereas NH3 maintained the same trend of previous years. From the statistical analysis emerges also that NH 3 has a different behavior respect to PM 2.5 and NOx, these latter being much more correlated between each other than NH 3 . However, further studies should be carried out on a bigger spatial and temporal scale.