The global oxygen budget and its future projection

Huang, Jianping; Huang, Jingxin; Liu, Xiaoyue; Li, Changyu; Ding, Lei

doi:10.1016/j.scib.2018.07.023

Cited by 83 publications

(67 citation statements)

References 26 publications

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“…In the troposphere, ozone formation is resulted from a complicated chemical process, and requires ozone precursors, such as VOCs (volatile organic carbons) and NO x = NO + NO 2 (nitrogen oxides) (Sillman, 1995). As the increase in industrial activity and number of automobiles, the precursors of ozone (O 3 ) and the global budget of oxidization are also significantly increased Huang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Ozone formation under low solar radiation in eastern China

Tie

Long

et al. 2019

Preprint

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Abstract. PM2.5, a particulate matter with a diameter of 2.5 micrometers or less, is one of the major components of the air pollution in eastern China. In the past few years, China's government made strong efforts to reduce the PM2.5 pollutions. However, another important pollutant (ozone) becomes an important problem in eastern China. Ozone (O3) is produced by photochemistry, which requires solar radiation for the formation of O3. Under heavy PM2.5 pollution, the solar radiation is often depressed, and the photochemical production of O3 is prohibited. This study shows that during fall in eastern China, under heavy PM2.5 pollutions, there were often strong O3 photochemical productions, causing a co-occurrence of high PM2.5 and O3 concentrations. This co-occurrence of high PM2.5 and O3 is un-usual and is the main focus of this study. Recent measurements show that there were often high HONO surface concentrations in major Chinese mega cities, especially during daytime, with maximum concentrations ranging from 0.5 to 2&#8201;ppbv. It is also interesting to note that the high HONO concentrations were occurred during high aerosol concentration periods, suggesting that there were additional HONO surface sources in eastern China. Under the high daytime HONO concentrations, HONO can be photo-dissociated to be OH radicals, which enhance the photochemical production of O3. In order to study the above scientific issues, a radiative transfer model (TUV; Tropospheric Ultraviolet-Visible) is used in this study, and a chemical steady state model is established to calculate OH radical concentrations. The calculations show that by including the OH production of the photo-dissociated of HONO, the calculated OH concentrations are significantly higher than the values without including this production. For example, by including HONO production, the maximum of OH concentration under the high aerosol condition (AOD&#8201;=&#8201;2.5) is similar to the value under low aerosol condition (AOD&#8201;=&#8201;0.25) in the no-HONO case. This result suggests that even under the high aerosol condition, the chemical oxidizing process for O3 production can occurred, which explain the co-occurrence of high PM2.5 and high O3 in fall season in eastern China. However, the O3 concentrations were not significantly affected by the appearance of HONO in winter. This study shows that the seasonal variation of solar radiation plays important roles for controlling the OH production in winter. When the solar radiation is in a very low level in winter, it reaches the threshold level to prevent the OH chemical production, even by including the HONO production of OH. This study provides some important scientific highlights to better understand the O3 pollutions in eastern China.

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Section: Introductionmentioning

confidence: 99%

Ozone formation under low solar radiation in eastern China

Tie

Long

et al. 2019

Preprint

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“…Consistent with our results on soil moisture, the NDVI turned to increase after the mid‐2000s over the northeast of China (Chu et al, ), indicating that the soil wetting benefited the ecological restoration. The restored productivity to eroded soil in drylands during the recent years will increase the CO 2 storage of soil, and a recent pause in the growth rate of atmospheric CO 2 was reported (Keenan et al, ), which can mitigate global warming (Huang, Yu, et al, ) and O 2 deficit (Huang et al, ). Besides, the decadal wetting during 2005–2017 will contribute to preventing more drought events and desertification from causing possible economic losses in the range of $42 billion annually (Winslow et al, ).…”

Section: Discussionmentioning

confidence: 99%

Decadal Change in Soil Moisture Over East Asia in Response to a Decade‐Long Warming Hiatus

et al. 2019

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East Asia has experienced long-term warming and drying in the twentieth century.However, a phenomenon known as the "warming hiatus" changed the trend of enhanced soil drying over East Asia. In contrast to the previous long-term drying in the last century, time series of soil moisture showed a shift from a downtrend to uptrend around 2005, and prominent wetting was located in the northeast (semiarid and dry subhumid regions) and southeast of China (extreme humid regions). Our results illustrated that such abrupt change in soil moisture was closely related to the change of warming during hiatus. The warming hiatus played a more important role in decadal soil wetting over these semiarid and dry subhumid regions, compared to relatively limited influence of surface atmosphere temperature over humid regions. The weakened drying during the hiatus decade suggests that the response of wetting/drying to climate in drylands is closely related to decadal surface atmosphere temperature, which will deepen our understanding of the mechanism on the role of surface atmosphere temperature in the process of wetting/drying in drylands over different time scales.

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“…The carbon emissions from respiration per individual in this study are only a rst-order approximation based on the above assumption. The CO 2 emission from one person is assumed to be 89.90 kg C yr − 1 in this study but varies over a range of 52.9-160 kg C yr − 1 (Additional le 1: Table S6) in other studies based on different methods or without considering different age groups and gender [16,18,63,[20][21][22]64]. The value used by Huang et al is much higher than other studies.…”

Section: Uncertainty Associated With the Parametersmentioning

confidence: 96%

The impact of human and livestock respiration on CO2 emissions from 14 global cities

Cai

Zeng

Zhao

et al. 2020

Preprint

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BackgroundThe CO2 released by humans and livestock through digestion and decomposition is an important part of the urban carbon cycle. But this part is reraly condidarded in the stuties of city carbon budget since its annual magnitude is lower than that of fossil fuel emissions within the boundaries of cities. However, human and livestock respiration may be substantial compared to fossil fuel emissions in areas with high population density such as Manhattan or Beijing. High-resolution datasets of CO2 release from respiration also have rarely been reported on a global scale or in cities globally. Here, we estimate the CO2 released by human and livestock respiration at global and large city scales and then compare it with the carbon emissions inventory from fossil fuels in 14 cities worldwide.ResultsThe results show that the total human and livestock respiration is up to 38.1% of fossil fuel emissions for Delhi among the studied cities. The proportion could be larger than 10% in cities of Sao Paulo, Cape Town and Tokyo. In other cities, it is raletivily small with a proportion around 5%, while Washington DC has the least proportion in 2.8%. In addition, almost 90% of respiratory carbon comes from urban areas in most cities, while up to one-third comes from suburban areas in Beijing on account of the siginificant livestock production.ConclusionThe results suggest that the respiration of humans and livestock represents a significant CO2 source in some cities and is nonnegligible for city carbon budget analysis and carbon monitoring.

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The global oxygen budget and its future projection

Cited by 83 publications

References 26 publications

Ozone formation under low solar radiation in eastern China

Ozone formation under low solar radiation in eastern China

Decadal Change in Soil Moisture Over East Asia in Response to a Decade‐Long Warming Hiatus

The impact of human and livestock respiration on CO2 emissions from 14 global cities

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