Data from: Insights into summertime surface ozone formation from diurnal variations in formaldehyde and nitrogen dioxide along a transect through New York City

Estimating tropospheric ozone (O3) production from observations is
challenging but possible given the close coupling of O3 with formaldehyde
(HCHO) and nitrogen dioxide (NO2), two remotely sensed air pollutants.
Previous reliance on once-daily satellite overpasses highlights the need
to study diurnal changes and surface-column relationships. Using surface
observations, Pandora spectrometer retrievals, and a high-resolution (1.33
km) air quality model (WRF-CMAQ), we characterize diurnal patterns of HCHO
and NO2 at seven locations along an upwind-downwind pathway through NYC
during June-August 2018. Diurnal patterns of the few available surface
HCHO concentrations suggest biogenic emission influence, while a bimodal
surface NO2 pattern implies local anthropogenic NOx emissions. Details of
these patterns vary by site: an afternoon NO2 spike at New Haven (CT)
indicates traffic emissions, while a delayed daily HCHO peak at Westport
(CT) relative to other sites likely reflects sea breeze dynamics. Peak
column concentrations generally lag surface peaks by about four hours,
occurring at 9-10 AM for morning NO2 (from Pandora and WRF-CMAQ) and
around 4 PM for midday HCHO (from WRF-CMAQ). TROPOMI overpass time at 1:30
PM misses peak column HCHO and NO2 concentrations. A box model (F0AM)
constrained with site-level observations and WRF-CMAQ fields indicates 1-9
ppb hr-1 higher noontime local O3 production rates on three sets of paired
high- versus mid-to-low-O3 days. F0AM sensitivity analyses on these six
days suggest a predominantly transitional O3 formation regime at urban and
downwind sites, differing at some sites from the NOx-saturated regime
diagnosed for summertime average conditions via the weekday-weekend
effect.