| Title: | Inferring Changes in Summertime Surface Ozone-NO(x)-VOC Chemistry over U.S. Urban Areas from Two Decades of Satellite and Ground-Based Observations |
| Author(s): | Jin X; Fiore A; Boersma KF; Smedt I; Valin L; |
| Address: | "Department of Earth and Environmental Sciences, Columbia University, New York, New York 10027, United States. Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, United States. Royal Netherlands Meteorological Institute, De Bilt 3730 AE, The Netherlands. Wageningen University, Environmental Sciences Group, Wageningen 6708 PB, The Netherlands. Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels 1180, Belgium. United States Environmental Agency, Office of Research and Development, Research Triangle Park, North Carolina 27709, United States" |
| ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Print) 0013-936X (Linking) |
| Abstract: | "Urban ozone (O(3)) formation can be limited by NO(x), VOCs, or both, complicating the design of effective O(3) abatement plans. A satellite-retrieved ratio of formaldehyde to NO(2) (HCHO/NO(2)), developed from theory and modeling, has previously been used to indicate O(3) formation chemistry. Here, we connect this space-based indicator to spatiotemporal variations in O(3) recorded by on-the-ground monitors over major U.S. cities. High-O(3) events vary nonlinearly with OMI HCHO and NO(2), and the transition from VOC-limited to NO(x)-limited O(3) formation regimes occurs at higher HCHO/NO(2) value (3 to 4) than previously determined from models, with slight intercity variations. To extend satellite records back to 1996, we develop an approach to harmonize observations from GOME and SCIAMACHY that accounts for differences in spatial resolution and overpass time. Two-decade (1996-2016) multisatellite HCHO/NO(2) captures the timing and location of the transition from VOC-limited to NO(x)-limited O(3) production regimes in major U.S. cities, which aligns with the observed long-term changes in urban-rural gradient of O(3) and the reversal of O(3) weekend effect. Our findings suggest promise for applying space-based HCHO/NO(2) to interpret local O(3) chemistry, particularly with the new-generation satellite instruments that offer finer spatial and temporal resolution" |
| Keywords: | *Air Pollutants/analysis Cities Environmental Monitoring *Ozone/analysis *Volatile Organic Compounds/analysis; |
| Notes: | "MedlineJin, Xiaomeng Fiore, Arlene Boersma, K Folkert Smedt, Isabelle De Valin, Lukas eng 80NSSC18K1399/ImNASA/Intramural NASA/ EPA999999/ImEPA/Intramural EPA/ Research Support, U.S. Gov't, Non-P.H.S. 2020/04/30 Environ Sci Technol. 2020 Jun 2; 54(11):6518-6529. doi: 10.1021/acs.est.9b07785. Epub 2020 May 14" |
