Agricultural Aerosols: The Impact of Farming Activity on Ice Nucleating Particles

Abstract

Farming activities cause particles such as soil dust and plant material to be emitted into the air. Some of these aerosols can become ice nucleating particles (INPs), serving as seeds for ice and mixed- phase clouds. While there have been ground- based studies of these particles in the western Great Plains and a single air- based study in Indiana, there is a distinct lack of ground- based studies in the Midwest. In Indiana, over two- thirds of the state is farmland, with over 75% of land in Tippecanoe County used for agriculture. Despite farming being such an essential part of life in Indiana, the connection between agricultural activities and INP concentrations in the area has not been explored. Using fi eld observations taken at the Purdue Agronomy Center for Research and Education (ACRE), we hope to study the impact of harvesting on INP concentrations in the midwestern United States. Th e fi eld experiment took place from May to December 2021 at the ACRE site, but this study focuses on three days during the harvesting period. Data was collected via two instruments: the SPectrometer for Ice Nuclei (SPIN) and the Cloud Condensation Nuclei Counter (CCNC). It appears there is an increase in INP concentrations on days when harvesting occurs, most likely due to an increase in organic and biological particles. It is hoped that the data from this project will provide further insight into the composition and number concentrations of INPs from harvesting through ground- based fi eld observations, as well as insight into INP concentration in the rural Midwest and its climatic impacts.