On the Regional and Seasonal Ozone Depletion Potential of Chlorinated Very Short‐Lived Substances

Hossaini, Ryan; Wild, Oliver; Chipperfield, Martyn P.; Wilson, Chris

doi:10.1029/2018gl081455

Cited by 29 publications

(33 citation statements)

References 51 publications

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“…Assessing the behaviour of the annual Antarctic ozone hole continues to be an important aspect of monitoring the impact of Montreal Protocol controls on ozone depleting substances (ODS) and for observing the effects of Antarctic ozone on the interactions between components of the climate system (Goyal et al 2019;Lickley et al 2020;Solomon et al 2020). While the Montreal Protocol is working to reduce stratospheric ozone loss (WMO 2018), recent increases in some ODS emissions have been identified (Montzka et al 2018;Claxton et al 2019;Fang et al 2019;Rigby et al 2019) with likely effects on recovery of Antarctic ozone (Dhomse et al 2019). At the same time, the accuracy in evaluating ozone trends is influenced by variability in stratospheric conditions and their relationship to large-scale climate modes (Zhang et al 2017;Chipperfield et al 2018;Maycock et al 2018;Ball et al 2019).…”

Section: Introductionmentioning

confidence: 99%

The Antarctic ozone hole during 2018 and 2019

Klekociuk

Tully

Krummel

et al. 2021

J. South. Hemisph. Earth Syst. Sci.

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While the Montreal Protocol is reducing stratospheric ozone loss, recent increases in some ozone depleting substance (ODS) emissions have been identified that may impact southern hemisphere climate systems. In this study, we discuss characteristics of the 2018 and 2019 Antarctic ozone holes using surface in situ, satellite and reanalysis data to gain a better understanding of recent ozone variability. These ozone holes had strongly contrasting characteristics. In 2018, the Antarctic stratospheric vortex was relatively stable and cold in comparison to most years of the prior decade. This resulted in a large and persistent ozone hole that ranked in the upper-tercile of metrics quantifying Antarctic ozone depletion. In contrast, strong stratospheric warming in the spring of 2019 curtailed the development of the ozone hole, causing it to be anomalously small and of similar size to ozone holes in the 1980s. As known from previous studies, the ability of planetary waves to propagate into the stratosphere at high latitudes is an important factor that influences temperatures of the polar vortex and the overall amount of ozone loss in any particular year. Disturbance and warming of the vortex by strong planetary wave activity were the dominant factors in the small 2019 ozone hole. In contrast, planetary wave disturbances to the vortex in the winter-spring of 2018 were much weaker than in 2019. These results increase our understanding of the impact of Montreal Protocol controls on ODS and the effects of Antarctic ozone on the southern hemisphere climate system.

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Section: Introductionmentioning

confidence: 99%

The Antarctic ozone hole during 2018 and 2019

Klekociuk

Tully

Krummel

et al. 2021

J. South. Hemisph. Earth Syst. Sci.

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“…The Cl VOCs are dominated by C 1 -C 2 compounds, which represent with ranging from 94.5% to 97.1% of the Cl VOCs . The Cl VOCs with C 1 -C 2 are also called chlorinated very short-lived substances (Cl VSLS ), which are significant sources of the stratospheric chlorines that contribute to ozone depletion (Claxton et al, 2019;Hossaini et al, 2017Hossaini et al, , 2019. The compounds dichloromethane (CH 2 Cl 2 ) and chloroform (CHCl 3 ), accounting for ∼90% and ∼25% of their tropospheric abundance from anthropogenic activities (Hossaini et al, 2015), respectively, are the relatively abundant Cl VSLS produced by the sintering process.…”

Section: Organic Chlorine Emissionsmentioning

confidence: 99%

Gaseous and Particulate Chlorine Emissions From Typical Iron and Steel Industry in China

Ding

et al. 2020

JGR Atmospheres

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The accurate estimation of chlorine emissions is urgently needed to evaluate regional and global atmospheric chlorination. This study first reports on the gaseous/particulate phases of chlorine emissions from typical integrated steel industries, including the major manufacturing processes (i.e., sintering, ironmaking, and steelmaking) and self‐owned coal‐fired power plant (CFPP). The concentration of chlorine species emitted from the ironmaking/steelmaking processes and the self‐owned CFPP is very low (<1 mg/Nm3). Owing to the combustion of chlorine‐rich sinter raw materials, the sintering processes emitted unexpectedly high concentrations of chlorinated substances, including chlorinated very short‐lived CH3Cl, CH2Cl2, C2H5Cl, and C2H4Cl2. Flue gas desulfurization (FGD) systems equipped on the sintering processes can slightly reduce chlorinated hydrocarbons emissions (ClVOCs). However, the chlorine species bonded in filterable/condensable particulate states (ClFPM/ClCPM) can be removed by high efficient systems (with efficiencies of 64.8–94.1% for ClFPM and 97.3–98.5% for ClCPM), relying on employed FGD technology. Owing to rapid rate at which FGD systems have been installed in China, ClInorganic gases, ClCPM, and ClFPM emissions from the sintering and iron industry in 2016 were reduced by 75.3%, 82.7%, and 45.6%, respectively. Our results indicate that the current ultralow‐emission equipment facilitates the reduction in chlorine emissions from iron and steel industry, but subsequent retrofits should give greater consideration to the simultaneous removal of ClVOCs.

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“…The most efficient transport pathway for Cl-VSLS into the stratosphere is suggested to be via the ASMA. This is why Cl-VSLS emissions from the region of continental Asia are suggested to have the highest ozone depletion potential (ODP) compared to emissions from other source regions (Claxton et al, 2019). Their regionally dependent ODP is estimated to be in the range of 0.0097 − 0.0208 (CH 2 Cl 2 ) and 0.0143 − 0.0264 (CHCl 3 ) (for comparison here the ODPs of some other chlorocarbons: CFC-11: 1; CCl 4 : 0.87; HCFC-22: 0.034; CH 3 Cl: 0.015; Carpenter et al, 2018;Claxton et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

In situ observations of CH2Cl2 and CHCl3 show efficient transport pathways for very short-lived species into the lower stratosphere via the Asian and North American summer monsoons

Lauther

Vogel

Wintel

et al. 2021

Preprint

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Abstract. Efficient transport pathways for ozone depleting very short-lived substances (VSLS) from their source regions into the stratosphere are a matter of current scientific debate, however they have yet to be fully identified on an observational basis. Understanding the increasing impact of chlorine containing VSLS (Cl-VSLS) on stratospheric ozone depletion is important in order to validate and improve model simulations and future predictions. We report on the first transport study using airborne in situ measurements of the Cl-VSLS dichloromethane (CH2Cl2) and trichloromethane (chloroform, CHCl3) to derive a detailed description of the two most efficient and fast transport pathways from (sub-)tropical source regions into the extratropical lower stratosphere (Ex-LS) in northern hemisphere (NH) late summer. The Cl-VSLS measurements were obtained in the upper troposphere and lower stratosphere (UTLS) above Western Europe and the mid latitude Atlantic Ocean in the frame of the WISE (Wave-driven ISentropic Exchange) aircraft campaign in autumn 2017 and are combined with the results from a three-dimensional simulation of a Lagrangian transport model as well as back-trajectory calculations. Compared to background measurements of similar age we find up to 150 % enhanced CH2Cl2 and up to 100 % enhanced CHCl3 mixing ratios in the Ex-LS. We link the measurements of enhanced mixing ratios to emissions in the region of southern and eastern Asia. Transport from this area to the Ex-LS at potential temperatures in the range of 370–400 K takes about 5–10 weeks via the Asian summer monsoon anticyclone (ASMA). Our measurements suggest anthropogenic sources to be the cause of these strongly elevated Cl-VSLS concentrations observed at the top of the lowermost stratosphere (LMS). A faster transport pathway into the Ex-LS is derived from particularly low CH2Cl2 and CHCl3 mixing ratios in the UTLS. These low mixing ratios reflect weak emission sources and a local seasonal minimum of both species in the boundary layer of Central America and the tropical Atlantic. We show that air masses uplifted by hurricanes, the North American monsoon, and general convection above Central America into the tropical tropopause layer to potential temperatures of about 360–370 K are transported isentropically within 1–5 weeks into the Ex-LS. This transport pathway linked to the North American monsoon mainly impacts the middle and lower part of the LMS with particularly low CH2Cl2 and CHCl3 mixing ratios. In a case study, we specifically analyze air samples directly linked to the uplift by the category 5 hurricane Maria that occurred during October 2017 above the Atlantic Ocean. Regionally differing CHCl3 : CH2Cl2 emission ratios derived from our UTLS measurements suggest a clear similarity between CHCl3 and CH2Cl2 when emitted by anthropogenic sources and differences between the two species mainly caused by additional, likely biogenic, CHCl3 sources. Overall, the transport of strongly enhanced CH2Cl2 and CHCl3 mixing ratios from southern and eastern Asia via the ASMA is the main factor for increasing the chlorine loading from the analyzed VSLS in the Ex-LS during NH late summer. Thus, further increases in Asian CH2Cl2 and CHCl3 emissions, as frequently reported in recent years, will further increase the impact of Cl-VSLS on stratospheric ozone depletion.

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On the Regional and Seasonal Ozone Depletion Potential of Chlorinated Very Short‐Lived Substances

Cited by 29 publications

References 51 publications

The Antarctic ozone hole during 2018 and 2019

The Antarctic ozone hole during 2018 and 2019

Gaseous and Particulate Chlorine Emissions From Typical Iron and Steel Industry in China

In situ observations of CH<sub>2</sub>Cl<sub>2</sub> and CHCl<sub>3</sub> show efficient transport pathways for very short-lived species into the lower stratosphere via the Asian and North American summer monsoons

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On the Regional and Seasonal Ozone Depletion Potential of Chlorinated Very Short‐Lived Substances

Cited by 29 publications

References 51 publications

The Antarctic ozone hole during 2018 and 2019

The Antarctic ozone hole during 2018 and 2019

Gaseous and Particulate Chlorine Emissions From Typical Iron and Steel Industry in China

In situ observations of CH&lt;sub&gt;2&lt;/sub&gt;Cl&lt;sub&gt;2&lt;/sub&gt; and CHCl&lt;sub&gt;3&lt;/sub&gt; show efficient transport pathways for very short-lived species into the lower stratosphere via the Asian and North American summer monsoons

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Product

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About

In situ observations of CH<sub>2</sub>Cl<sub>2</sub> and CHCl<sub>3</sub> show efficient transport pathways for very short-lived species into the lower stratosphere via the Asian and North American summer monsoons