Inferring Changes in Summertime Surface Ozone–NOx–VOC Chemistry over U.S. Urban Areas from Two Decades of Satellite and Ground-Based Observations

Jin, Xiaomeng; Fiore, Arlene M.; Boersma, K. F.; Smedt, Isabelle De; Valin, L. C.

doi:10.1021/acs.est.9b07785

Cited by 186 publications

(240 citation statements)

References 82 publications

(182 reference statements)

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“…The hourly comparison of mean concentration values of March and April 2019 with March and April 2020 showed a declining trend in O 3 concentrations. This diurnal variation in this station suggested that O 3 concentrations have been reduced during the lockdown period in response to a decrease in ozone precursor emissions, as NO x , occurring in rural areas (Jin et al 2020;Simon et al 2015). Meteorological conditions, such as temperature, could affect the O 3 trends but, as discussed previously, the meteorological data were almost similar prior to and during the lockdown periods, not influencing changes in air pollutant concentrations.…”

Section: Background Stationssupporting

confidence: 56%

“…Accordingly, there are two sensitivity regimes of O 3 production, namely, the NO x -limited and VOC-limited regimes. In the NO x -limited regime, generally in rural areas (Jin et al 2020), an increase in NO x values leads to an increase in ozone production which shows to be only slightly affected by VOC variations. In the VOC-limited regime, generally in urban areas (Witte et al 2011), ozone increases with increasing VOC and decreases with increasing NO x .…”

Section: Introductionmentioning

confidence: 98%

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Nitrogen dioxide reductions from satellite and surface observations during COVID-19 mitigation in Rome (Italy)

Bassani

Vichi

Esposito

et al. 2021

Environ Sci Pollut Res

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Lockdown restrictions were implemented in Italy from 10 March 2020 to contain the COVID-19 pandemic. Our study aims to evaluate air pollution changes, with focus on nitrogen dioxide (NO2), before and during the lockdown in Rome and in the surroundings. Significant NO2 declines were observed during the COVID-19 pandemic with reductions of − 50%, − 34%, and − 20% at urban traffic, urban background, and rural background stations, respectively. Tropospheric NO2 vertical column density (VCD) from the TROPOspheric Monitoring Instrument (TROPOMI) was used to evaluate the spatial-temporal variations of the NO2 before and during the lockdown for the entire area where the surface stations are located. The evaluation is concerned with the pixels including one or more air quality stations to explore the capability of the unprecedented high spatial resolution to monitor urban and rural sites from space with relation to the surface measurements. Good agreement between surface concentration and TROPOMI VCD was obtained in Rome (R = 0.64 in 2019, R = 0.77 in 2020) and in rural sites (R = 0.71 in 2019). Inversely, a slight correlation (R = 0.20) was observed in rural areas during the lockdown due to very low levels of NO2. Finally, the TROPOMI VCD showed a sharp decline in NO2, larger in urban (− 43%) than in rural sites (− 17%) as retrieved with the concurrent surface measurements averaging all the traffic and urban background (− 44%) and all the rural background stations (− 20%). These results suggest air pollution improvement in Rome gained from implementing lockdown restrictions.

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Section: Background Stationssupporting

confidence: 56%

Section: Introductionmentioning

confidence: 98%

Nitrogen dioxide reductions from satellite and surface observations during COVID-19 mitigation in Rome (Italy)

Bassani

Vichi

Esposito

et al. 2021

Environ Sci Pollut Res

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“…For example, NO x emissions can titrate (i.e., remove) ozone, reducing concentrations. Therefore, lower NO 2 can, in some cases and depending on the chemistry [47][48][49][50][51] , lead to higher ozone levels; this potential pattern may be especially important in urban areas. Decreasing NO 2 increases VOC:NOx ratios, which can increase secondary organic aerosol yields, leading to increased PM 2.5 concentrations [52][53][54][55][56] .…”

Section: Discussionmentioning

confidence: 99%

PM2.5 and Ozone Air Pollution Levels Have Not Dropped Consistently Across the US Following Societal Covid Response

Bekbulat¹,

Apte²,

Millet³

et al. 2020

Preprint

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Analysis of a large national dataset of fine particulate matter (PM2.5) and ozone air pollution from the US Environmental Protection Agency indicate opposing differences in average concentrations during the covid response period, relative to expected levels. These are the two most important pollutants in terms of public health impacts and non-attainment in the US. Post- covid response, average PM2.5 levels are modestly higher (~10%) than expected; average ozone levels are lower (~7%). However, the size of the post-response ozone anomaly is decreasing with time. In addition, no individual US state had lower-than-expected PM2.5 for all weeks post- covid response, and only one US state (California) met that criteria for ozone. Two non-covid factors, meteorology and regional transport, do not fully explain observed trends. These findings are unexpected given the large reduction in many household’s activities associated with “stay at home” and other covid responses. We hypothesize that this result partly arises from the fact that ozone and the majority of PM2.5 are secondary pollutants formed in the atmosphere from emissions from many sources (i.e., not just traffic). Preliminary analysis of nitrogen dioxide (NO2) data in a few cities reveals substantially lower-than-expected (~31%) concentrations post-covid. NO2 is a primary pollutant and is much more strongly associated with traffic than PM2.5 or ozone.

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“…The satellite-based HCHO to NO 2 ratio has been used to infer whether ozone formation is limited by NO x or VOCs or in transition between regimes (Duncan et al, 2010;Jin & Holloway, 2015;Martin et al, 2004). Our ongoing research demonstrates that satellite-based HCHO/NO 2 generally captures the observed nonlinear dependence of ozone production on NO x and VOCs (Jin et al, 2020). In addition, observed decadal changes in spatiotemporal patterns of ground-level ozone, known to occur as ozone formation chemistry transitions to stronger NO x sensitivity, are linked directly to satellite HCHO/NO 2 trends over several U.S. metropolitan areas.…”

Section: 1029/2020gh000270mentioning

confidence: 97%

Using Satellites to Track Indicators of Global Air Pollution and Climate Change Impacts: Lessons Learned From a NASA‐Supported Science‐Stakeholder Collaborative

et al. 2020

Self Cite

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The 2018 NASA Health and Air Quality Applied Science Team (HAQAST) "Indicators" Tiger Team collaboration between NASA-supported scientists and civil society stakeholders aimed to develop satellite-derived global air pollution and climate indicators. This Commentary shares our experience and lessons learned. Together, the team developed methods to track wildfires, dust storms, pollen counts, urban green space, nitrogen dioxide concentrations and asthma burdens, tropospheric ozone concentrations, and urban particulate matter mortality. Participatory knowledge production can lead to more actionable information but requires time, flexibility, and continuous engagement. Ground measurements are still needed for ground truthing, and sustained collaboration over time remains a challenge. Plain Language Summary Recent advances in satellite remote sensing enable observation-based tracking of climate change and air pollution with relatively high spatial resolution globally. The 2018 NASA Health and Air Quality Applied Science Team (HAQAST) "Indicators" Tiger Team launched a collaboration between~20 NASA-supported scientists and civil society stakeholders to develop satellite-derived global air pollution and climate indicators. This Commentary demonstrates the range of air quality and climate change tracking uses for satellite data and shares our experience and lessons learned, which can inform future problem-driven science-stakeholder collaborative efforts. Together, the team developed methods to track wildfires, dust storms, pollen, urban green space, nitrogen dioxide concentrations and asthma burdens, tropospheric ozone concentrations, and urban fine particulate matter mortality. Lessons learned include that participatory knowledge production can lead to more actionable information for stakeholders but requires time and dedicated attention. Stakeholder engagement is valuable at each stage, from developing more nascent data sets to operationalizing mature data sets. Flexibility is critical, since stakeholder needs evolve and new synergies emerge when there are engagements across a wide range of stakeholders and teams. However, additional ground measurements are needed to ground truth satellite observations, and

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Inferring Changes in Summertime Surface Ozone–NO_x–VOC Chemistry over U.S. Urban Areas from Two Decades of Satellite and Ground-Based Observations

Cited by 186 publications

References 82 publications

Nitrogen dioxide reductions from satellite and surface observations during COVID-19 mitigation in Rome (Italy)

Nitrogen dioxide reductions from satellite and surface observations during COVID-19 mitigation in Rome (Italy)

PM2.5 and Ozone Air Pollution Levels Have Not Dropped Consistently Across the US Following Societal Covid Response

Using Satellites to Track Indicators of Global Air Pollution and Climate Change Impacts: Lessons Learned From a NASA‐Supported Science‐Stakeholder Collaborative

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