Collaborative Research: Determination of Secondary Organic Aerosol Formation from Cyanobacterial Harmful Algal Blooms Through Coupled Laboratory and Field Experiments

University Of North Carolina At Chapel Hill, Chapel Hill NC

Investigators

Abstract

This project aims to improve understanding of the impact of cyanobacterial harmful algal blooms (cHABs) on the atmosphere. cHABs have been observed in freshwater lakes in all 50 US states and are increasing in frequency, severity, and spatial extent due to anthropogenic factors. This study addresses the knowledge gap regarding biogenic volatile organic compound (BVOC) emissions to the atmosphere from cHABs and the potential for cHABs to cause secondary organic aerosol (SOA) formation. A series of laboratory and field measurements, along with chemical modeling, will be performed. Advancing the understanding of SOA production due to cHABs addresses societally important issues of air quality and radiative forcing. The project includes education and research opportunities for high school teachers and students. To test the hypothesis that cHAB-SOA is a significant contributor to total SOA in regions with substantial cHABs, three scientific objectives will be targeted: (1) Determine SOA formation from hydroxyl radical oxidation of cHAB-BVOC in the absence and presence of pre-existing inorganic aerosols in the laboratory. (2) Measure cHAB-BVOC species and SOA production adjacent to a cHAB through field measurements. (3) Box model SOA production and species evolution using gas and particle data from lab and field measurements to evaluate potential contributions to atmospheric SOA. In the laboratory, a series of oxidation experiments investigating key BVOCs will be conducted using an oxidative flow reactor or chamber. In the field, using a variety of instrumentation, sampling will take place at Grand Lake St. Mary’s in Ohio, which has a predictable and intense cHAB each year. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.