Wintertime Formaldehyde: Airborne Observations and Source Apportionment Over the Eastern United States

Formaldehyde (HCHO) is generated from direct urban emission sources and secondary production the photochemical reactions of smog. HCHO linked to tropospheric ozone formation, contributes other components In this study, pollution plume intercepts during Wintertime INvestigation Transport, Emissions, Reactivity (WINTER) campaign were used investigate characterize formation in relation several anthropogenic tracers. Analysis aircraft combined with detailed chemical box modeling downwind cities suggests that most important contribution observed was primary emission. A model analysis a single suggested contribute 21 ± 10% HCHO. Ratios HCHO/CO northeast US, Ohio New York, ranging 0.2% 0.6%, are consistent emissions at modest production. nocturnal boundary layer residual repeated vertical profiling over influenced areas indicate flux 1.3 × 1014 molecules cm?2 h?1. case study Atlanta, GA, nighttime exhibited ratio CO (0.6%–1.8%) anti-correlated O3. Observations mixing between air masses those by more rapid The ratios determined measured data 2.3–15 times greater than NEI 2017 database. largest 1.7%–1.8%, located near co-generating power stations.