Kai-Lan Chang's research while affiliated with University of Colorado and other places

... due to a longer growing season with rising air temperature (Proietti et al., 2020;Sicard et al., 2020). Hence, O 3 -control policies require integrated consideration of atmospheric chemistry, and O 3 remains a persistent environmental issue, especially in the northern hemisphere (Akimoto and Tanimoto, 2022;Cuesta et al., 2021;Malashock et al., 2022). ...

... We apply data quality-control measures to exclude unreliable data outliers and select stations with continuous observations from 2014 to 2021 for trend analysis. Following previous studies 19,54,52 , we exclude data points (1) with values greater than 500 ppbv or less than 0 ppbv, (2) with an hourly standardized value ( z i = ...

... Neighborhood-scale CTM simulations are computationally expensive, which has limited our ability to simulate full seasons or multiple years. Previous studies have demonstrated that internal meteorological variability can have profound consequences on pollutant concentrations (Fiore et al., 2022;Garcia-Menendez et al., 2017), and this facet should be remembered when considering our results. A key example from our study is the high O 3 concentration in our April 2019 simulation. ...

... PM 10 and O 3 are considered to represent a major part of the problem [12]. Ozone exposure has significantly increased worldwide, leading to a 46% increase in ozoneattributable mortality from 2000 to 2019 [13]. PM 10 and O 3 are linked to a rise in all-cause, cardiovascular, and respiratory mortalities [11,[14][15][16][17][18]. ...

... These findings, together with Figure 1, imply a role for convective lofting of ozone and precursors to the free troposphere, where ozone production is more efficient and the lifetime is longer than near the surface, A c c e p t e d M a n u s c r i p t in driving the overall increase in the tropospheric ozone burden (Berntsen et al., 1996;Naik et al., 2005;Sauvage et al., 2007). Increasing aircraft NO x emissions over this period may also play role in the overall burden increase (Wang et al., 2022). The ozone increases in the lower troposphere are largest in the first two decades of the simulation, more in line with the overall trends in global anthropogenic emissions (Table S2). ...

... About 74% of the European Union (EU) population lives in cities (European Council, 2016). In these urban environments, the most harmful air pollutants in terms of human health effects are tropospheric ozone (O 3 ), particles with an aerodynamic diameter lower than 2.5 μm (PM 2.5 ), and nitrogen dioxide (NO 2 ) (Anenberg et al., 2022;Malashock et al., 2022;Southerland et al., 2022). These pollutants are associated with hospital admissions and premature deaths for respiratory and cardiovascular diseases (e.g., Samoli et al., 2011;Hoek et al., 2013;Atkinson et al., 2014;Cohen et al., 2017;Nuvolone et al., 2018;Khomenko et al., 2021;Zhang et al., 2022). ...

... Ozone precursor emissions (i.e.,NO x (NO + NO 2 ) and CO) are generated from various sources, including power plants, industrial boilers, cement kilns, turbines, cars, trucks, and off-road vehicles (including boats, construction equipment, etc.) Borhani et al., 2016aBorhani et al., , 2017bBorhani et al., , 2019Borhani et al., , 2023Cheraghi & Borhani, 2016a, 2016bHoveidi et al., 2017;Maddah et al., 2022;Mazzeo et al., 2005;Motesaddi Zarandi et al., 2015). Ozone concentrations are usually measured using ground-based and satellite systems (Chang et al., 2022;Massagué et al., 2022;Reshi et al., 2022;Wang et al., 2021). For example, Borhani et al. (2022c) investigated the changes in tropospheric ozone and its relation to ozone precursors (i.e., CO, NO 2 , and NO) and meteorological conditions observed at 22 groundbased stations of the Air Quality Control Company (AQCC) in Tehran from 2001 to 2020. ...

... accessed on 23 January 2023). Specifically, the warm-season average of 8-h daily maximum O 3 concentrations were estimated by the Bayesian maximum entropy method by combining the O 3 ground measurement and chemical transport model estimates [24]. In situ O 3 measurement data were retrieved from the Tropospheric Ozone Assessment Report and the China National Environmental Monitoring Center Network. ...

... Our modelling analysis confirms that the increase of ozone concentration observed during the lockdown in many urban locations (see e.g. Gkatzelis et al., 2021;Sokhi et al., 2022) is limited to the cities, major roads and large conurbation areas, while rural background areas show different behaviours, with prevailing ozone concentration decrease, in agreement with the observational analyses provided by Cristofanelli et al. (2021) and Steinbrecht et al. (2021) and with model simulation results obtained for central to southern Europe by Matthias et al. (2021). ...

... The same meteorology was applied to all runs to eliminate the influence of future climate change on air quality. Chemically active stratospheric species (such as O 3 , NO, NO 2 , and N 2 O 5 ) were prescribed as monthly mean distributions using climatology from the Whole Atmospheric Community Climate Model simulations Zhang et al., 2021). ...