TROPOMI NO2 in the United States: A detailed look at the annual averages, weekly cycles, effects of temperature, and correlation with PM2.5

Goldberg, Daniel L.; Anenberg, Susan C.; Mohegh, Arash; Lü, Zifeng; Streets, D. G.

doi:10.1002/essoar.10503422.1

Cited by 25 publications

(19 citation statements)

References 63 publications

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“…However, when the normalized data are smoothed with 28‐day rolling mean values, the correlation improved with a correlation coefficient of 0.75 for both the pre‐lockdown and the lockdown/post‐lockdown periods (Figures 4e and 4f). This is consistent with other studies involving satellite tropNO 2 data where 28‐day rolling means or weekly averaging was carried out to minimize noise and data gaps (Goldberg et al., 2021; Misra et al., 2021).…”

Section: Resultssupporting

confidence: 90%

“…(2020) report that the Los Angeles basin was unusually wet in 2020, especially during the late March and early April 2020. Other researchers who correlated daily surface observations of NO 2 and TROPOMI tropNO 2 for 35 different stations in Europe reported similar findings and they found that correlation improved after averaging the data to monthly time scales (Cersosimo et al., 2020; Goldberg et al., 2021; Ialongo et al., 2020). The comparison for the lockdown and post‐lockdown period of March through November is shown in Figure 4b; the correlation remains the same ( r = 0.39) but the one interesting feature is that the tropNO 2 and on‐road emissions are very small during the lockdown compared to the pre‐lockdown.…”

Section: Resultsmentioning

confidence: 59%

“…The TROPOMI tropNO 2 data captures the day‐to‐day variability in tropospheric NO 2 concentrations but due to cloud cover, varying background tropNO 2 , and uncertainties associated with assumptions such as a priori profile and lower sensitivity to near surface NO 2 , on certain days the tropNO 2 retrievals do not adequately represent the changes in near surface NO 2 (Cersosimo et al., 2020; Goldberg et al., 2021; Ialongo et al., 2020). The tropospheric NO 2 variability is very well captured; however, on monthly scales and even on weekly scales, to the extent that weekday/weekend cycles are noticeable.…”

Section: Discussionmentioning

confidence: 99%

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COVID‐19 Induced Fingerprints of a New Normal Urban Air Quality in the United States

et al. 2021

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As the 2019 novel Corona virus (COVID-19) spread from China to other parts of the world, various countries imposed lockdown measures one by one. Reports of improved air quality from ground and satellite observations of aerosol optical depth (AOD) and nitrogen dioxide (NO 2 ) soon followed in the media as documented by Kondragunta et al. (2020). The precipitous drops seen in the tropospheric vertical column NO 2, (trop-NO 2 here onward) measured by the Sentinel 5P TROPOspheric Monitoring Instrument (TROPOMI) were substantial, especially during the strict lockdown period for each country (Gkatzelis et al., 2021). Goldberg et al. (2020) reported that in the United States (US), tropNO 2 decreased by 9.2%-45% in 26 cities from March 15 to April 30, 2020 compared to the same period in 2019; these reported reductions account for the influence of the weather. Other researchers reported similar findings, mainly reductions of tropNO 2 attributed to reductions in traffic emissions both in the US and across the globe in major urban areas of Europe, India,

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 59%

Section: Discussionmentioning

confidence: 99%

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COVID‐19 Induced Fingerprints of a New Normal Urban Air Quality in the United States

et al. 2021

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“…Observations with retrieved cloud fractions greater than 0.1 or flagged as poor quality or snow-covered (that is, TROPOMI quality assurance flag <0.75) are excluded. Although the resolution of TROPOMI observations is 3.5 × 5.5 km 2 , several studies have demonstrated that oversampling techniques can provide accurate NO 2 maps at 1 × 1 km 2 resolution when averaging over a one-month period 31,32,54 . An area-weighted oversampling technique 55,56 is used to map daily satellite NO 2 column observations from TROPOMI onto a ~0.01° × 0.01° (~1 × 1 km 2 ) resolution grid and from OMI to a 0.1° × 0.125° (~10 × 10 km 2 ) grid, as these resolutions balance the need of fine resolution for observing fine-scale structure and of minimizing the effects of sampling biases and noise in the observations.…”

Section: Datamentioning

confidence: 99%

“…The newest remote sensing spectrometer, the European Space Agency's TROPOspheric Monitoring Instrument (TROPOMI) 30 on the Copernicus Sentinel 5p satellite, has been providing NO 2 observations with finer spatial resolution and higher instrument sensitivity since 2018. These attributes allow the generation of TROPOMI NO 2 maps at 100 times finer resolution (approximately 1 × 1 km 2 ) with a one-month averaging period 31,32 , an improvement over the spatial and temporal averaging needed for accurate OMI maps (typically approximately 10 × 10 km 2 over one year) 24 . Concurrently, the excellent stability of the OMI instrument over the last 15 years provides an ideal dataset for long-term trend analysis 28,33 that offers context for recent TROPOMI data.…”

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confidence: 99%

Global fine-scale changes in ambient NO2 during COVID-19 lockdowns

Cooper

Martin

Hammer

et al. 2022

Nature

133

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Nitrogen dioxide (NO2) is an important contributor to air pollution and can adversely affect human health1–9. A decrease in NO2 concentrations has been reported as a result of lockdown measures to reduce the spread of COVID-1910–20. Questions remain, however, regarding the relationship of satellite-derived atmospheric column NO2 data with health-relevant ambient ground-level concentrations, and the representativeness of limited ground-based monitoring data for global assessment. Here we derive spatially resolved, global ground-level NO2 concentrations from NO2 column densities observed by the TROPOMI satellite instrument at sufficiently fine resolution (approximately one kilometre) to allow assessment of individual cities during COVID-19 lockdowns in 2020 compared to 2019. We apply these estimates to quantify NO2 changes in more than 200 cities, including 65 cities without available ground monitoring, largely in lower-income regions. Mean country-level population-weighted NO2 concentrations are 29% ± 3% lower in countries with strict lockdown conditions than in those without. Relative to long-term trends, NO2 decreases during COVID-19 lockdowns exceed recent Ozone Monitoring Instrument (OMI)-derived year-to-year decreases from emission controls, comparable to 15 ± 4 years of reductions globally. Our case studies indicate that the sensitivity of NO2 to lockdowns varies by country and emissions sector, demonstrating the critical need for spatially resolved observational information provided by these satellite-derived surface concentration estimates.

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COVID-19 lockdowns reveal pronounced disparities in nitrogen dioxide pollution levels

Kerr

Goldberg

Anenberg

2020

Preprint

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The unequal spatial distribution of ambient nitrogen dioxide (NO2), an air pollutant related to traffic, leads to higher exposure for minority and low socioeconomic status communities. We exploit the unprecedented drop in urban activity during the COVID-19 pandemic and use high-resolution, remotely-sensed NO2 observations to investigate disparities in NO2 levels across different demographic subgroups in the United States. We show that COVID-19 lockdowns reduced, but did not eliminate, the overall racial, ethnic, and socioeconomic NO2 disparities. Prior to the pandemic, satellite-observed NO2 levels in the least white census tracts of the United States were double NO2 levels in the most white tracts. During the pandemic, the largest lockdown-related NO2 reductions occurred in urban neighborhoods that have 30% fewer white residents and 111% more Hispanic residents than neighborhoods with the smallest reductions, likely driven by the greater density of highways and interstates in these racially and ethnically diverse areas. However, the least white tracts still experienced 50% higher NO2 levels during the lockdowns than the most white tracts experienced prior to the pandemic. Future policies aimed at eliminating pollution disparities will need to look beyond reducing emissions from only passenger traffic and also consider other collocated sources of emissions such as heavy-duty trucks, power plants, and industrial facilities.

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TROPOMI NO2 in the United States: A detailed look at the annual averages, weekly cycles, effects of temperature, and correlation with PM2.5

Cited by 25 publications

References 63 publications

COVID‐19 Induced Fingerprints of a New Normal Urban Air Quality in the United States

COVID‐19 Induced Fingerprints of a New Normal Urban Air Quality in the United States

Global fine-scale changes in ambient NO2 during COVID-19 lockdowns

COVID-19 lockdowns reveal pronounced disparities in nitrogen dioxide pollution levels

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