Measurements of Hydroxyl Radical (OH)/Nitric Acid (HNO3) for Program for Research on Oxidants: Photochemistry, Emissions, and Transport (PROPHET)

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

A recently built instrument capable of measuring atmospheric OH (hydroxyl radical), H2SO4 (sulfuric acid), and HNO3 (nitric acid) will be deployed during the 2001 Summer intensive of PROPHET (Program for Research on Oxidants: Photochemistry, Emissions, and Transport) in Northern Michigan. The measurement technique is based on chemical ionization mass spectrometry (CIMS). In earlier PROPHET campaigns, measurements using a fluorescence-based technique showed the surprising result of measurable levels of OH during the night. Deploying this fundamentally different technique could confirm the occurrence of nighttime OH under the conditions of the PROPHET site. The measurements of H2SO4 will complement ongoing aerosol measurements, and the measurements of HNO3 would complement measurements of other individual compounds in the reactive nitrogen (NOy) family.