Ambient Formaldehyde over the United States from Ground-Based (AQS) and Satellite (OMI) Observations

This study evaluates formaldehyde (HCHO) over the U.S. from 2006 to 2015 by comparing ground monitor data Air Quality System (AQS) and a satellite retrieval Ozone Monitoring Instrument (OMI). Our comparison focuses on utility of inform patterns, trends, processes ground-based HCHO across We find that cities with higher levels biogenic volatile organic compound (BVOC) emissions, including primary HCHO, exhibit larger diurnal amplitudes in surface observations. These differences hour-to-hour variability suggests agreement may depend distribution emission sources. On seasonal basis, OMI exhibits highest correlation AQS summer lowest winter. The ratios versus other seasons show pronounced OMI, likely due changes vertical distribution. is more than at surface, 20–100% also has latitude dependency, regions. agrees interannual certain periods, whereas do not consistent decadal trend. possibly rather large which makes small drift less significant. Temperature explains part variabilities. Small temperature variations western are reflected quiescent region. decrease summertime southeast could be partially explained negative trend local temperatures.