- 1NOAA, Chemical Sciences Laboratory, Boulder, United States of America (steven.s.brown@noaa.gov)
- 2Department of Chemistry, University of Colorado, Boulder, USA
- 3Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, USA
- 4NOAA Global Monitoring Laboratory, Boulder, USA
- *A full list of authors appears at the end of the abstract
The NOAA Chemical Sciences Laboratory has led a series of recent airborne campaigns in the U.S. to investigate urban air quality, emissions and greenhouse gases. The Atmospheric Emissions and Reactivity Observed from Megacities to Marine Areas (AEROMMA) flew the three largest U.S. cities (New York, Chicago and Los Angeles) in 2023 on the NASA DC-8 with a comprehensive suite of trace gases, aerosols, radiation and meteorology. The Airborne and Remote Sensing Methane and Air Pollutant Surveys (AiRMAPS) is a series of campaigns sampling urban areas and oil and gas basins over 3 years. Airborne measurements during AEROMMA probed nonlinear O3 photochemistry in New York, Chicago and Los Angeles. The mean ozone production efficiency (OPE), the ratio of Ox (O3 + NO2) to NOx oxidation product enhancements, were 9 ± 4 (1 s), 6 ± 3 and 6 ± 3 ppbv ppbv-1, respectively. OPE exhibited a nonlinear, inverse dependence on total reactive nitrogen (NOy, a proxy for initial NOx) and a positive correlation with ∆VOC/∆NOy. A zero-dimensional photochemical model supports these observed OPE dependences on NOx and VOCs and shows that OPE is a distinct metric from total O3 production that may be informative to the development of O3 pollution control strategies. AEROMMA flights also quantified the magnitude and sources of urban methane (CH4) emission from in-situ measurements of CH4, CO2, CO, and C2-C5 alkanes in Los Angeles. Using the CA Air Resources Board CO emissions inventory alongside CH4/CO enhancement ratios, the analysis determines summertime CH4 and C2–C5 alkanes emissions. Roughly half of Los Angeles CH4emissions are from natural gas sources and half from sources such as landfills and dairies. Comparison to historical aircraft campaigns from 2010-2023 shows declining CH4 but increasing ethane emissions, with the latter due to changes in pipeline natural gas ethane content.
Sunil Baidar, Xinrong Ren, Andrew Rollins, Eleanor Waxman, Kristin Zuraski, Michael Robinson, Chris Jernigan, Gordon Novak, Patrick Veres, Matthew Coggon, Kelvin Bates, Chelea Stockwell, Lu Xu Georgios Gkatzelis, Jessica Gilman, Morgan Selby, Victoria Treadaway, Coby Franceour, Hendrik Fuchs, Anna Novelli, Aaron Staisby, Glenn Wolfe, Birger Bohn, Brian McDonald, Rebecca Schwantes, Carsten Warneke.
How to cite: Brown, S., Chace, W., Woamck, C., Schafer, N., and Peischl, J. and the The AEROMMA and AiRMAPS Teams: Urban Air Quality and Greenhouse Gases from Recent Airborne Field Campaigns in the United States, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14289, https://doi.org/10.5194/egusphere-egu25-14289, 2025.