Air quality impacts of COVID-19 lockdown measures detected from space using high spatial resolution observations of multiple trace gases from Sentinel-5P/TROPOMI
<p>The aim of this paper is to highlight how TROPOspheric Monitoring Instrument (TROPOMI) trace gas data can best be used and interpreted to understand event-based impacts on air quality from regional to city scales around the globe. For this study, we present the observed changes in the atmos...
| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/10319/2022/acp-22-10319-2022.pdf |
| Summary: | <p>The aim of this paper is to highlight how TROPOspheric Monitoring Instrument (TROPOMI) trace
gas data can best be used and interpreted to understand event-based impacts
on air quality from regional to city scales around the globe. For this
study, we present the observed changes in the atmospheric column amounts of
five trace gases (NO<span class="inline-formula"><sub>2</sub></span>, SO<span class="inline-formula"><sub>2</sub></span>, CO, HCHO, and CHOCHO) detected by the
Sentinel-5P TROPOMI instrument and driven by reductions in anthropogenic
emissions due to COVID-19 lockdown measures in 2020. We report clear
COVID-19-related decreases in TROPOMI NO<span class="inline-formula"><sub>2</sub></span> column amounts on all
continents. For megacities, reductions in column amounts of tropospheric
NO<span class="inline-formula"><sub>2</sub></span> range between 14 % and 63 %. For China and India, supported by
NO<span class="inline-formula"><sub>2</sub></span> observations, where the primary source of anthropogenic SO<span class="inline-formula"><sub>2</sub></span> is
coal-fired power generation, we were able to detect sector-specific emission
changes using the SO<span class="inline-formula"><sub>2</sub></span> data. For HCHO and CHOCHO, we consistently
observe anthropogenic changes in 2-week-averaged column amounts over China
and India during the early phases of the lockdown periods. That these
variations over such a short timescale are detectable from space is due to
the high resolution and improved sensitivity of the TROPOMI instrument. For
CO, we observe a small reduction over China, which is in concert with the
other trace gas reductions observed during lockdown; however, large
interannual differences prevent firm conclusions from being drawn. The joint
analysis of COVID-19-lockdown-driven reductions in satellite-observed trace
gas column amounts using the latest operational and scientific retrieval
techniques for five species concomitantly is unprecedented. However, the
meteorologically and seasonally driven variability of the five trace gases
does not allow for drawing fully quantitative conclusions on the reduction
in anthropogenic emissions based on TROPOMI observations alone. We
anticipate that in future the combined use of inverse modeling techniques
with the high spatial resolution data from S5P/TROPOMI for all observed
trace gases presented here will yield a significantly improved
sector-specific, space-based analysis of the impact of COVID-19 lockdown
measures as compared to other existing satellite observations. Such analyses
will further enhance the scientific impact and societal relevance of the
TROPOMI mission.</p> |
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| ISSN: | 1680-7316 1680-7324 |