Can Column Formaldehyde Observations Inform Air Quality Monitoring Strategies for Ozone and Related Photochemical Oxidants?

Formaldehyde column density (ΩHCHO) showed a potentially useful correlation with surface ozone during the LISTOS campaign on Long Island Sound and KORUS-AQ in Seoul, South Korea. This builds previous work that identified this relationship from situ aircraft observations similar findings for ground-based airborne remote sensing of ΩHCHO. In region, ΩHCHO exhibited strong temporal (r2 = 0.66) spatial 0.73) correlation. The variability (∼1 Dobson units [DU]) was larger than range average (∼0.1 DU). is most informing monitoring strategies, demonstrating challenge using satellite data sets purpose. high levels NO2 resulted Ox better correlating due to titration effects. ΩHCHO–Ox may therefore reflect sum related photochemical oxidants, relevant air quality standards set regulate quantity such as U.S. EPA National Ambient Air Quality Standard (NAAQS). shifted Seoul need evaluate over longer time periods. With sufficient precision future retrievals, could be evaluating adequacy strategies.