{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,8]],"date-time":"2026-06-08T11:27:59Z","timestamp":1780918079914,"version":"3.54.1"},"reference-count":51,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2018,6,23]],"date-time":"2018-06-23T00:00:00Z","timestamp":1529712000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>A conservative downscaling technique was applied when comparing nitrogen dioxide (NO2) column densities from space-borne observations and a fine-scale regional model. The conservative downscaling was designed to enhance the spatial resolution of satellite measurements by applying the fine-scale spatial structure from the model, with strict mass conservation at each satellite footprint pixel level. With the downscaling approach, NO2 column densities from the Ozone Monitoring Instrument (OMI; 13 \u00d7 24 km nadir footprint resolution) and the Global Ozone Monitoring Experiment-2 (GOME-2; 40 \u00d7 80 km) show excellent agreement with the Community Multiscale Air Quality (CMAQ; 4 \u00d7 4 km) NO2 column densities, with R = 0.96 for OMI and R = 0.97 for GOME-2. We further introduce an approach to reconstruct surface NO2 concentrations by combining satellite column densities and simulated surface-to-column ratios from the model. Compared with the Environmental Protection Agency\u2019s (EPA) Air Quality System (AQS) surface observations, the reconstructed surface concentrations show a good agreement; R = 0.86 for both OMI and GOME-2. This study demonstrates that the conservative downscaling approach is a useful tool to compare coarse-scale satellites with fine-scale models or observations in urban areas for air quality and emissions studies. The reconstructed fine-scale surface concentration field could be used for future epidemiology and urbanization studies.<\/jats:p>","DOI":"10.3390\/rs10071001","type":"journal-article","created":{"date-parts":[[2018,6,25]],"date-time":"2018-06-25T11:03:25Z","timestamp":1529924605000},"page":"1001","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3968-6145","authenticated-orcid":false,"given":"Hyun Cheol","family":"Kim","sequence":"first","affiliation":[{"name":"Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USA"},{"name":"Cooperative Institute for Climate and Satellites, University of Maryland, College Park, MD 20742, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7781-2029","authenticated-orcid":false,"given":"Sang-Mi","family":"Lee","sequence":"additional","affiliation":[{"name":"South Coast Air Quality Management District, Diamond Bar, CA 91765, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tianfeng","family":"Chai","sequence":"additional","affiliation":[{"name":"Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USA"},{"name":"Cooperative Institute for Climate and Satellites, University of Maryland, College Park, MD 20742, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fong","family":"Ngan","sequence":"additional","affiliation":[{"name":"Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USA"},{"name":"Cooperative Institute for Climate and Satellites, University of Maryland, College Park, MD 20742, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li","family":"Pan","sequence":"additional","affiliation":[{"name":"Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USA"},{"name":"Cooperative Institute for Climate and Satellites, University of Maryland, College Park, MD 20742, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pius","family":"Lee","sequence":"additional","affiliation":[{"name":"Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,6,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1939","DOI":"10.1016\/S0140-6736(03)13582-9","article-title":"Personal exposure to nitrogen dioxide (NO2) and the severity of virus-induced asthma in children","volume":"361","author":"Chauhan","year":"2003","journal-title":"Lancet"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"362","DOI":"10.1016\/j.envpol.2007.06.012","article-title":"Human health effects of air pollution","volume":"151","author":"Kampa","year":"2008","journal-title":"Environ. 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