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For the last two years Acdan has worked with Brad Pierce, SSEC director and UW\u2013Madison Atmospheric and Oceanic Sciences professor, to study ozone production around Lake Michigan using satellite data. Due in part to ozone transport from other regions, that area has struggled to keep ozone levels below federal air quality standards set by the US Environmental Protection Agency. Acdan\u2019s research builds on results from the Lake Michigan Ozone Study field campaign of 2017 to look at the precursors of ozone. <\/p>\n\n\n\n
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UW\u2013Madison graduate student Jerrold Acdan has been studying ozone production around Lake Michigan using satellite data. Credit: Jerrold Acdan<\/figcaption><\/figure><\/div>\n\n\n\n
\u201cOzone production can be thought of as NOx<\/sub> (nitrogen oxides) sensitive or VOC (volatile organic compound) sensitive,\u201d says Acdan.<\/p>\n\n\n\n Acdan used data from the TROPOspheric Monitoring Instrument on the Copernicus Sentinel-5 Precursor satellite and EPA Photochemical Assessment Monitoring Stations on the ground as input for a formaldehyde (a type of VOC) to nitrogen dioxide ratio (FNR) to study these sensitivities over time. A higher ratio indicates more NOx<\/sub> sensitivity while a lower ratio indicates more VOC sensitivity. Previous studies have attempted to establish the appropriate threshold between NOx<\/sub> sensitivity and VOC sensitivity. Acdan, however, focused on comparing thresholds from two studies to determine which would better apply to satellite data.<\/p>\n\n\n\n Acdan compared ozone season and ozone exceedance day composites and found that on Chicago ozone exceedance days, ozone production in the Chicago Metropolitan Area remains VOC sensitive, but the western shore of Lake Michigan tends to be more NOx<\/sub> sensitive. The same analysis also led Acdan to conclude that the FNR thresholds for ozone-NOx<\/sub>-VOC sensitivity published by Duncan et al. 2010 are more appropriate for interpreting surface measurements while those published by Jin et al. 2020 are more appropriate for interpreting satellite data in the Lake Michigan Region.<\/p>\n\n\n\n Acdan is finishing up a Master\u2019s thesis and preparing to start his Ph.D. work in Fall 2021. He\u2019ll be tackling a similar research project but looking at a different area of the country \u2014 analyzing data from the 2018 Long Island Sound Tropospheric Ozone Study field campaign using high resolution models and NASA airborne measurements. Long term, he plans to continue in the field of atmospheric chemistry.<\/p>\n\n\n\n \u201cHopefully I can go back home one day and maybe work for something like the California Air Resources Board or the EPA in California and make an impact on public health related to air quality,\u201d says Acdan.<\/p>\n\n\n\n This work was partially supported by the Lake Michigan Air Directors Consortium (LADCO).<\/em><\/p>\n\n\n\n Duncan, B. N., Yoshida, Y., Olson, J. R., Sillman, S., Martin, R. V., Lamsal, L., … Crawford, J. H.: Application of OMI observations to a space-based indicator of NOxand VOC controls on surface ozone formation<\/a>. Atmos.Environ., 44, 18, 2213-2223, doi: 10.1016\/j.atmosenv.2010.03.010, 2010.<\/p>\n\n\n\n