A 15-year record (2001–2015) of the ratio of nitrate to non-sea-salt sulfate in precipitation over East Asia

Itahashi, Syuichi; Yumimoto, Keiya; Uno, Itsushi; Hayami, Hiroshi; Fujita, Shohei; Pan, Yuepeng; Wang, Yuesi

doi:10.5194/acp-18-2835-2018

Cited by 63 publications

(52 citation statements)

References 56 publications

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“…From 2006 to 2015, wet deposition of sulfate exhibited a significant decrease ( p < 0.01) at Jinyunshan, Shizhan, and Xiangzhou stations, and a slight decrease in Xiaoping station. Similar results have been reported by Itahashi et al (2018) and Zhang et al (2018). The noteworthy reduction in sulfate was attributable to decreased wet scavenging of sulfate aerosols and gaseous SO 2 with the reduction in SO 2 emissions.…”

Section: Resultssupporting

confidence: 92%

“…have been reported by Itahashi et al (2018) and Zhang et al (2018). The noteworthy reduction in sulfate was attributable to decreased wet scavenging of sulfate aerosols and gaseous SO 2 with the reduction in SO 2 emissions.…”

Section: Journal Of Geophysical Research: Atmospheresmentioning

confidence: 62%

“…The simulated nitrate ion concentrations in precipitation showed a flat trend, with a relatively large increase of 11.4 μeq/L in southwestern China. Similarly, a recent study based on long‐term EANET observations (Itahashi et al, 2018) also shows that the temporal variation in the nitrate concentration in precipitation did not correspond to the variation in NO x emissions in China, and it did not increase significantly despite NO x emissions doubling from 2000–2010. We conducted the sensitivity simulation with 2006 NO x emissions in 2015 meteorological year, and it also demonstrates that the variation of NO x emissions between 2006 and 2015 had a negligible effect on precipitation acidification over China.…”

Section: Resultsmentioning

confidence: 99%

“…Our simulated ratios are broadly consistent with previous reports for the similar period. A recent study based on the EANET observations in China calculated the ratio of nitrate to sulfate in precipitation (the inverse of the S/N ratios used in our study) from 2001 to 2015 (Itahashi et al, 2018). They found that the averaged ratios from those measurements in China showed a continuous increase, from ~0.3 (3.3 for the S/N) in 2006 to 0.6 (1.6 for the S/N) in 2015.…”

Section: Resultsmentioning

confidence: 99%

“…Accompanied with the reduction in SO 2 emissions, we expect that nitric acid might play an increasingly important role in precipitation acidification. Local measurements of precipitation ionic compositions in China indicate that the ratios of nitrate to sulfate ions in precipitation have been increasing in the past decade (Itahashi et al, 2018; Li et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Trends of Precipitation Acidification and Determining Factors in China During 2006–2015

Liu

Song

et al. 2020

JGR Atmospheres

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Precipitation acidification, often termed as acid rain (pH < 5.6), has been recognized as one of the major environmental issues in China since the 1980s and exerted detrimental effects on terrestrial ecosystems. In this study, we present the first investigation on the evolution of precipitation acidification over China during 2006–2015 based on a long‐term nationwide precipitation observation network and chemical transport model (Weather Research and Forest model coupled with Chemistry) simulations. The observations demonstrate a clearly decreasing trend in precipitation acidification across China from 2006 to 2015. The percentages of the number of the stations experiencing heavy acidic precipitation (annual mean pH < 5.0) decrease from ~50% in 2006 to 20% in 2015, and those with pH < 4.5 decrease from 25% to less than 5%. Our model simulations reproduced this trend and show the notable decrease in the terrestrial area (from 30% to 16%) experiencing the mean precipitation pH < 5.6. The simulation experiments indicate that the mitigation of the acidification issue in China stemmed from the large reduction in SO2 emissions (by about 60% from 2006 to 2015), which would limit the formation of sulfate and also increase the wet scavenging of gaseous ammonia. The contributions of sulfuric acid on precipitation acidification were estimated to decrease from 0.70–0.82 to 0.44–0.60 from 2006 to 2015 over northern, southern, and southwestern China. This study suggests that nitric acid plays a more important role in acidifying precipitation in northern China at present, while sulfuric acid is still the dominant factor in southern areas.

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Section: Resultssupporting

confidence: 92%

Section: Journal Of Geophysical Research: Atmospheresmentioning

confidence: 62%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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