Ozone, oxides of nitrogen, and carbon monoxide during pollution events over the eastern United States: An evaluation of emissions and vertical mixing

Abstract

[1] Chemical transport models such as the Community Multiscale Air Quality (CMAQ) model provide useful guidance on air pollution control strategies. We evaluate the performance of a 12 km resolution CMAQ simulation with surface and aircraft observations of CO, O 3 , and NO x during the summer of 2002. When all data are considered, on average, modeled and observed CO total column contents (surface to 3,000 m) agreed to within 14% in the morning and 22% in the afternoon. Reducing the deposition velocity for CO improves model-measurement agreement but did not eliminate the model bias. The majority of observed vertical profiles have a maximum near the surface. Although many observed spirals had a secondary maximum at the top of the boundary layer, indicating subgrid-scale shallow convection. The model was not able to replicate these vertical structures. Water vapor profiles likewise showed greater vertical variability in the observations than in the model. General conclusions from these model-measurement comparisons: total CO emissions estimates are either adequate or underestimated,

Measured and modeled CO and NO y in DISCOVER-AQ: An evaluation of emissions and chemistry over the eastern US

“…In the BWR, Castellanos et al (2011) found, from comparing observations in the RAMMPP campaign to CMAQ model output, that NEI CO emissions were correct or slightly underestimated while NO x emissions from mobile sources were likely overestimated. There is little agreement among these studies on the NEI's accuracy, for either CO or NO x , showing both under-and overestimation for both species.…”

Impact of lightning-NO on eastern United States photochemistry during the summer of 2006 as determined using the CMAQ model

“…They found that median model columns were too low at rural locations and too high at urban locations. Castellanos et al (2011) also found high biases at urban locations and local biases at rural locations when comparing compared CMAQcalculated NO y -HNO 3 with "NO 2 " measurements at rural and urban monitoring sites over the eastern United States. These differing biases are important because they suggest that the lifetime of NO 2 (see Henderson et al, 2011) and/or the transport of NO x (see Gilliland et al, 2008) is underestimated by regional models.…”

CAMx ozone source attribution in the eastern United States using guidance from observations during DISCOVER‐AQ Maryland

“…Many studies show an overestimate, by up to a factor of two, of total reactive oxidized nitrogen (NO y ) in regional air quality models compared to observations [Doraiswamy et al, 2009;Castellanos et al, 2011;Yu et al, 2012;Brioude et al, 2013;Anderson et al, 2014;Goldberg et al, 2014]. Some link the calculation of too much NO y to the overestimate of NO x emissions from area sources [Doraiswamy et al, 2009], while others link it to an overestimate of NO x emissions from commercial marine vessels [Brioude et al, 2013].…”

“…This may be linked to the challenge of simulating ozone precursors: NO x (NO x = NO+NO 2 ) and volatile organic compounds (VOCs) [Castellanos et al, 2011;Zhou et al, 2013;Canty et al, 2015]. For any given ozone concentration, there can be many different production pathways; empirical kinetic modeling approach (EKMA) diagrams [Kinosian, 1982;Chameides et al, 1992;Sillman, 1999], highlight this non-linear dependence of ozone production on NO x and VOCs.…”