| Autor: |
Simon, Heather, Valin, Luke C., Baker, Kirk R., Henderson, Barron H., Crawford, James H., Pusede, Sally E., Kelly, James T., Foley, Kristen M., Chris Owen, R., Cohen, Ronald C., Timin, Brian, Weinheimer, Andrew J., Possiel, Norm, Misenis, Chris, Diskin, Glenn S., Fried, Alan |
| Zdroj: |
Journal of Geophysical Research - Atmospheres; March 2018, Vol. 123 Issue: 6 p3304-3320, 17p |
| Abstrakt: |
Modeled source attribution information from the Community Multiscale Air Quality model was coupled with ambient data from the 2011 Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality Baltimore field study. We assess source contributions and evaluate the utility of using aircraft measured CO and NOyrelationships to constrain emission inventories. We derive ambient and modeled ΔCO:ΔNOyratios that have previously been interpreted to represent CO:NOyratios in emissions from local sources. Modeled and measured ΔCO:ΔNOyare similar; however, measured ΔCO:ΔNOyhas much more daily variability than modeled values. Sector‐based tagging shows that regional transport, on‐road gasoline vehicles, and nonroad equipment are the major contributors to modeled CO mixing ratios in the Baltimore area. In addition to those sources, on‐road diesel vehicles, soil emissions, and power plants also contribute substantially to modeled NOyin the area. The sector mix is important because emitted CO:NOxratios vary by several orders of magnitude among the emission sources. The model‐predicted gasoline/diesel split remains constant across all measurement locations in this study. Comparison of ΔCO:ΔNOyto emitted CO:NOyis challenged by ambient and modeled evidence that free tropospheric entrainment, and atmospheric processing elevates ambient ΔCO:ΔNOyabove emitted ratios. Specifically, modeled ΔCO:ΔNOyfrom tagged mobile source emissions is enhanced 5–50% above the emitted ratios at times and locations of aircraft measurements. We also find a correlation between ambient formaldehyde concentrations and measured ΔCO:ΔNOysuggesting that secondary CO formation plays a role in these elevated ratios. This analysis suggests that ambient urban daytime ΔCO:ΔNOyvalues are not reflective of emitted ratios from individual sources. Modeling and ambient analysis suggest that atmospheric processing can impact the ΔCO:ΔNOymeasured by aircraft over the Baltimore regionFor about one third of measurements, NOyvalues derived from different instruments lead to observed ΔCO:ΔNOythat are statistically inconsistentWe urge caution in using ΔCO:ΔNOyderived from aircraft measurement to quantify emissions errors from specific sources |
| Databáze: |
Supplemental Index |
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