The atmospheric concentrations and emissions of major halocarbons in China during 2009–2019

Yi, Liying; Wu, Jing; An, Minde; Xu, Weijun; Fang, Xuekun; Yao, Bo; Li, Yixi; Gao, Deyuan; Zhao, Xingchen; Hu, Jianxin

doi:10.1016/j.envpol.2021.117190

Cited by 36 publications

(45 citation statements)

References 36 publications

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“…However, as reported in recent studies in the North China Plain and in this study, the mixing ratios of CFC-11 seemed to increase to higher levels; CFC-11 mixing ratios as high as 307 ± 20 ppt were observed at the same MT site in 2015 . Nevertheless, our observation data, including these at YC and JZB sites during 2012–2014 and that at DY site during 2018, together with the results at the same DY site in a previous study in 2017, still revealed a decreasing trend in CFC-11 mixing ratios in the rural areas of Shandong province at a rate of −3.8 ppt year –1 ( r 2 = 0.84) during 2012–2018 (Figure ), faster than those of −1.2 ppt year –1 at MLO from 2012 to 2018 and −0.8 ppt year –1 for the all of China from 2009 to 2019 estimated by Yi et al…”

Section: Resultssupporting

confidence: 84%

“…CFC-11 mixing ratios from this study and those reported in China from previous studies − ,,,,,− (Table S3): empty symbols, CFC-11 mixing ratios reported in previous studies; filled symbols, CFC-11 mixing ratios measured in this study; horizontal error bars, sampling duration for each study; vertical solid line, standard deviation of CFC-11 mixing ratios; light green solid line, CFC-11 mixing ratios from 2000 to 2018 at Mauna Loa Observatory (MLO) in the NOAA monitoring network; light green shaded area, standard deviation of CFC-11 mixing ratios at MLO; gray dashed line, declining trend (−3.8 ppt year –1 ) for observed CFC-11 mixing ratios in Shandong.…”

Section: Resultsmentioning

confidence: 78%

“…The ambient mixing ratios of CFC-11 from previous studies in China are pooled together (Figure and Table S3). − ,,,,,− They seemed to show a decreasing trend before 2012 in China’s megacities, including the Pearl River Delta, Shanghai, and Beijing. However, as reported in recent studies in the North China Plain and in this study, the mixing ratios of CFC-11 seemed to increase to higher levels; CFC-11 mixing ratios as high as 307 ± 20 ppt were observed at the same MT site in 2015 .…”

Section: Resultsmentioning

confidence: 99%

“…CFC-11 had been used primarily as a refrigerant and foam blowing agent and was supposed to be released from banks such as air conditioners or foams only after its complete phase-out. , The emissions of CFC-11 that were far from what was expected from banks , were found to be largely or entirely attributed to the rigid polyurethane (PU) foam industry, , with CFC-11 emission either from the foaming process or from rigid polyurethane foams being a significant portion of the CFC-11 bank . Faced with the CFC-11 crisis in eastern China and the differences in emission estimates of CFC-11 based on observations outside mainland China, we thought it would be better to have local monitoring data to confirm and constrain the estimated emissions, yet data about ambient CFC-11 in mainland China in recent decades are quite sparse, − particularly after 2012 in eastern China. As Shandong and Hebei provinces of China are suggested to be major regions with increased emissions of CFC-11 in eastern mainland China, in this study we present field observation data from five campaigns carried out from 2012 to 2018 in Shandong province and estimate CFC-11 emissions in eastern mainland China on the basis of these observations.…”

Section: Introductionmentioning

confidence: 99%

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Constraining Emission Estimates of CFC-11 in Eastern China Based on Local Observations at Surface Stations and Mount Tai

Huang

Zhang

Xue

et al. 2021

Environ. Sci. Technol. Lett.

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While observations at global background sites in east Asia suggested unexpectedly increased emissions of trichlorofluoromethane (CFC-11) after 2012 in eastern China, particularly in Shandong province, there is a lack of local monitoring data to constrain the emission estimates. Here we report observations of ambient CFC-11 during 2012–2018 in Shandong province at five sites, including three rural sites and two background sites [one at Tuoji Island (TJI) in the Bohai Sea and the other at Mount Tai (MT), 1534 m above sea level]. The mixing ratios of CFC-11 at rural sites were 17–23% above the global background levels at Mauna Loa, Hawaii, and observations at MT and TJI revealed larger enhancements occurring in air masses traveling through the polyurethane foam industry region of the Shandong Peninsula. On the basis of the ratios of CFC-11 to tracers such as carbon monoxide (CO), chloroform (CHCl3), and carbon tetrachloride (CCl4) at the MT and TJI sites, the estimated emissions of CFC-11 in eastern China ranged from 12.0 ± 1.6 to 20.8 ± 3.9 Gg year–1 with an average of 14.7 ± 4.3 Gg year–1 in 2014 and 2017–2018. These tracer-based estimates may represent the upper limits due to relatively higher ratios of CFC-11 to tracers in the hot spot province.

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Section: Resultssupporting

confidence: 84%

Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Constraining Emission Estimates of CFC-11 in Eastern China Based on Local Observations at Surface Stations and Mount Tai

Huang

Zhang

Xue

et al. 2021

Environ. Sci. Technol. Lett.

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“…et al(2021) reported that the concentrations of CFC-11 and CFC-12 measured at the top of Mount Tai in northern China from 2017 to 2018 were 257 ppt and 577 ppt, respectively(Yang et al, 2021). The surface mean mixing ratio of CFC-11 in five cities in China (Beijing, Hangzhou, Guangzhou, Lanzhou and Chengdu) observed from 2017 to 2019 was in the range of 244 to 268 ppt, and that of CFC-12 ranged from 526 to 585 ppt during 2015 to 2019(Yi et al, 2021).Benish et al (2021) found concentrations of (281 ± 44) ppt for CFC-11 and (552 ± 93) ppt for CFC-12 from aircraft observations at 500-3500 m above…”

mentioning

confidence: 97%

Retrieval of Atmospheric CFC-11 and CFC-12 from High-resolution FTIR Observations at Hefei and Comparisons with Satellite Data

Zeng

Wang

Liu

et al. 2022

Preprint

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Abstract. Synthetic halogenated organic chlorofluorocarbons (CFCs) play an important role in stratospheric ozone depletion, and contribute signiﬁcantly to the greenhouse effect. In this work, the mid-infrared solar spectra measured by ground-based high-resolution Fourier transform infrared spectroscopy (FTIR) were used to retrieve atmospheric CFC-11 (CCl3F) and CFC-12 (CCl2F2) at Hefei, China. We implemented a new retrieval strategy, and analyzed the retrieval errors. The CFC-11 columns observed from January 2017 to December 2020 and CFC-12 columns from September 2015 to December 2020 show a similar annual decreasing trend and seasonal cycle, with an annual rate of (−0.47 % ± 0.16) % yr−1 and (−0.79 ± 0.31) % yr−1, respectively. CFC-11 total columns were higher in summer, and CFC-12 total columns were higher in summer and autumn. Both of CFC-11 and CFC-12 total columns reached the lowest in spring. The annual decreasing rate of near-surface concentration is (−0.60 ± 0.26) % y−1 for CFC-11, and (−0.81 ± 0.25) % y−1 for CFC-12. So the decline rate of CFC-11 is significantly lower than that of CFC-12. Further, FTIR data were compared with the ACE-FTS satellite data, WACCM (Whole Atmosphere Community Climate Model) data and the data from other NDACC (Network for the Detection of Atmospheric Composition Change) station. The mean relative difference between the vertical profiles observed by FTIR and ACE-FTS is (−5.6 ± 3.3) % and (4.8 ± 0.9) % for CFC-11 and CFC-12 for altitude from 5.5 to 17.5 km, respectively. The results demonstrate our FTIR data agree relatively well with the ACE-FTS satellite data. The annual decreasing rate of CFC-11 measured from ACE-FTS and calculated by WACCM are (−1.15 ± 0.22) % and (−1.68 ± 0.18) %, respectively. The interannual decreasing rates of atmospheric CFC-11 obtained from ACE-FTS and WACCM data are higher than that from FTIR observations. Also, the annual decreasing rate of CFC-12 from ACE-FTS and WACCM is (–0.85 ± 0.15) % and (–0.81 ± 0.05) %, respectively, close to the corresponding values from the FTIR measurements. Further, the total columns of CFC-11 observed at the Hefei site are very close to those at St. Petersburg station, with a mean difference of 3.63 × 1012 molec·cm-2, while the total columns of CFC-12 are 1.69 × 1014 molec·cm-2, slightly higher than those at St. Petersburg station.

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Organic Chlorofluoro Hydrocarbons

Gadagbui,

Onyema

2023

Patty's Toxicology

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This chapter is about organic chlorofluoro hydrocarbons, which are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F). In the early 1930s, chlorofluorocarbons (CFCs) were introduced in the 1930s as “safe” replacements for refrigerants such as sulfur dioxide, ammonia, carbon tetrachloride, and chloroform. The list was later expanded during World War II to include their use to produce insecticide aerosols to protect the troops in tropical areas against malaria and other insect‐borne diseases. Current usages include foam blowing, precision cleaning, and propellants for medicinal, cosmetic, and general‐purpose aerosols, air conditioning, and refrigeration. The expanded use of these CFCs has resulted in their emissions into the atmosphere. The CFCs have low chemical reactivity, long atmospheric lifetime, and are globally distributed. However, since they are ozone‐depleting and are also powerful greenhouse gases (GHGs), development was initiated to replace them with comparatively less ozone‐depleting and less greenhouse‐warming hydrochlorofluorocarbons (HCFCs). Subsequently, hydrofluorocarbons (HFCs) were developed that were both less ozone‐depleting and less GHGs accumulating. Both CFCs and HCFCs are controlled under the Montreal Protocol. The widespread use concerns about their environmental and human health effects of these substances have been extensively reviewed. This chapter updates information on the health effects of some of the major and minor CFCs, HCFCs, and HFCs, their global emissions estimates, the discrepancies, if any, between the major reporting regions and the global atmospheric emissions values, and the likely sources of the gap between the atmospheric measurements and the reported emissions.

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The atmospheric concentrations and emissions of major halocarbons in China during 2009–2019

Cited by 36 publications

References 36 publications

Constraining Emission Estimates of CFC-11 in Eastern China Based on Local Observations at Surface Stations and Mount Tai

Constraining Emission Estimates of CFC-11 in Eastern China Based on Local Observations at Surface Stations and Mount Tai

Retrieval of Atmospheric CFC-11 and CFC-12 from High-resolution FTIR Observations at Hefei and Comparisons with Satellite Data

Organic Chlorofluoro Hydrocarbons

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