Tropospheric ozone production and chemical regime analysis during the COVID-19 lockdown over Europe

Nussbaumer, Clara M.; Pozzer, Andrea; Tadić, Ivan; Röder, Lenard; Obersteiner, Florian; Harder, Hartwig; Lelieveld, Jos; Fischer, H.

doi:10.5194/acp-22-6151-2022

Cited by 10 publications

(9 citation statements)

References 70 publications

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“…While there was a drop in electricity generation rates at the beginning of the lockdown periods, most of the power plants were running at business-as-usual setting, resulting in limited changes in the background SO 2 concentrations and the overall columnar density. The behaviour of ozone concentrations during and immediately after COVID-19 is still a topic of many on-going investigations [64,65]. One theory is that a drop in NO x emissions altered the local photochemistry to produce marginally more ozone during the lockdowns and subsequently settled back into the seasonal pattern.…”

Section: Source Apportionmentmentioning

confidence: 99%

What Is Polluting Delhi’s Air? A Review from 1990 to 2022

Guttikunda

Dammalapati²,

Pradhan³

et al. 2023

Sustainability

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Delhi’s annual average PM2.5 concentration in 2021–22 was 100 μg/m3—20 times more than the WHO guideline of 5 μg/m3. This is an improvement compared to the limited information available for the pre-CNG-conversion era (~30%), immediately before and after 2010 CWG (~28%), and the mid-2010s (~20%). These changes are a result of continuous technical and economic interventions interlaced with judicial engagement in various sectors. Still, Delhi is ranked the most polluted capital city in the world. Delhi’s air quality is a major social and political concern in India, often with questions regarding its severity and primary sources, and despite several studies on the topic, there is limited consensus on source contributions. This paper offers insight by reviewing the influence of Delhi’s urban growth since 1990 on pollution levels and sources and the evolution of technical, institutional, and legal measures to control emissions in the National Capital Region of Delhi.

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Section: Source Apportionmentmentioning

confidence: 99%

What Is Polluting Delhi’s Air? A Review from 1990 to 2022

Guttikunda

Dammalapati²,

Pradhan³

et al. 2023

Sustainability

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“…In particular, during five days with coordinated flights over Germany (23,26,and 28 May) and over the North Atlantic (30 May, 2 June), the payload offered the opportunity to probe the air masses in more detail. An overview of the BLUESKY mission is given in Voigt et al (2022), and further detailed studies are published by Schumann et al (2021a, b), Reifenberg et al (2022), Nussbaumer et al (2022), Hamryszczak et al (2022), andKrüger et al (2022). In the present study we will focus on the sulfur compounds in the upper troposphere and lower stratosphere.…”

Section: Bluesky Missionmentioning

confidence: 99%

“…Additionally, the trace gases CO and O 3 on board HALO are considered in the present study for altitudes above 8 km. CO was measured by the TRacer In Situ TDLAS for Atmospheric Research (TRISTAR; Schiller et al, 2008) with a total uncertainty of 3 % for tropospheric measurements (Nussbaumer et al, 2022). Note that due to a small nitrous oxide (N 2 O) interference the uncertainty in the lower stratosphere is higher (8.5 ± 3.9 ppbv).…”

Section: Instrumentationmentioning

confidence: 99%

Enhanced sulfur in the upper troposphere and lower stratosphere in spring 2020

et al. 2022

Self Cite

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Abstract. Sulfur compounds in the upper troposphere and lower stratosphere (UTLS) impact the atmosphere radiation budget, either directly as particles or indirectly as precursor gas for new particle formation. In situ measurements in the UTLS are rare but are important to better understand the impact of the sulfur budget on climate. The BLUESKY mission in May and June 2020 explored an unprecedented situation. (1) The UTLS experienced extraordinary dry conditions in spring 2020 over Europe, in comparison to previous years, and (2) the first lockdown of the COVID-19 pandemic caused major emission reductions from industry, ground, and airborne transportation. With the two research aircraft HALO and Falcon, 20 flights were conducted over central Europe and the North Atlantic to investigate the atmospheric composition with respect to trace gases, aerosol, and clouds. Here, we focus on measurements of sulfur dioxide (SO2) and particulate sulfate (SO42-) in the altitude range of 8 to 14.5 km which show unexpectedly enhanced mixing ratios of SO2 in the upper troposphere and of SO42- in the lowermost stratosphere. In the UT, we find SO2 mixing ratios of (0.07±0.01) ppb, caused by the remaining air traffic, and reduced SO2 sinks due to low OH and low cloud fractions and to a minor extent by uplift from boundary layer sources. Particulate sulfate showed elevated mixing ratios of up to 0.33 ppb in the LS. We suggest that the eruption of the volcano Raikoke in June 2019, which emitted about 1 Tg SO2 into the stratosphere in northern midlatitudes, caused these enhancements, in addition to Siberian and Canadian wildfires and other minor volcanic eruptions. Our measurements can help to test models and lead to new insights in the distribution of sulfur compounds in the UTLS, their sources, and sinks. Moreover, these results can contribute to improving simulations of the radiation budget in the UTLS with respect to sulfur effects.

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“…The exploration of key driving forces for O3 pollution has become a hot topic for scientific community. During COVID-19 period, VOCs and NOx levels experienced substantial changes due to strict emission control measures, and both of these compositions further affected radical chemistry and O3 change (Goldberg et al, 2022;Nussbaumer et al, 2022). It provided us an unprecedent opportunity to fill the knowledge gap about the responses of O3 and radical chemistry to the drastic changes of precursor emissions, which facilitated the optimization of emission control strategy.…”

Section: Introductionmentioning

confidence: 99%

The impact of COVID-19 lockdown on ozone budget and radical chemistry in a typical industrial city of China

Cui

Wang

2022

Preprint

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Ozone (O 3 ) levels in East China suffered from rapid increases during the COVID-19 period. To clarify the reason for the O 3 increase, a continuous campaign was performed in a industrial city in North China Plain (NCP). Meanwhile, the machinelearning technique and the box model were employed to reveal the mechanisms of O 3 increase from the perspective of meteorology and photochemical process, respectively. The result suggested that the ambient O 3 level in Tangshan increased from 18.7 ± 4.63 to 45.6 ± 8.52 μg/m 3 (143%) after COVID-19 lockdown, and the emission reduction and meteorology contributed to 77% and 66% of this increment, respectively. The higher Wind speed (WS) coupled with regional transport played a significant role on O 3 increase (30.8 kg/s). The O 3 sensitivity verified that O 3 production was highly volatile organic compounds (VOC)-sensitive (Relative incremental reactivity (RIR): 0.75), while the NOx showed the negative impact on O 3 production in Tangshan (RIR:-0.59). It suggested that the control of VOCs rather than NOx might be more effective in reducing O 3 level in Tangshan because it was located on the VOC-limited regime. Besides, both of ozone formation potential (OFP) analysis and observation-based model (OBM) demonstrated that the alkenes (36.3 ppb) and anthropogenic oxygenated volatile organic compounds (OVOCs) (15.2 ppb) showed the higher OFP compared with other species, and their reactions released a large number of HO 2 and RO 2 radicals. Moreover, the concentrations of these species did not experience marked decreases after COVID-19 lockdown, which were major contributors to O 3 increase during this period.

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Tropospheric ozone production and chemical regime analysis during the COVID-19 lockdown over Europe

Cited by 10 publications

References 70 publications

What Is Polluting Delhi’s Air? A Review from 1990 to 2022

What Is Polluting Delhi’s Air? A Review from 1990 to 2022

Enhanced sulfur in the upper troposphere and lower stratosphere in spring 2020

The impact of COVID-19 lockdown on ozone budget and radical chemistry in a typical industrial city of China

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