An Approach for Assessing Human Respiration CO<subscript>2</subscript> Emissions Using Radiocarbon Measurements and Bottom‐Up Data Sets.
In: Journal of Geophysical Research. Atmospheres, Jg. 129 (2024-05-16), Heft 9, S. 1-11
Online
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Zugriff:
Carbon dioxide (CO2) is a major greenhouse gas in the atmosphere and has large impacts on climate change. Its fossil fuel (CO2ff) and biogenic (CO2bio) sources are well investigated, while CO2 emissions from human respiration (CO2hr), a subset of CO2bio, have received less attention. Especially as a source of carbon emissions in densely populated megacities, the role of CO2hr emissions in the carbon cycles was largely neglected. Here we fully characterize the respiratory CO2 emission rates (CERs) of Chinese people for the first time. Using the example of the megacity Beijing in China, we estimate the CO2hr emissions and present a method for quantifying its fraction in the atmospheric CO2 based on radiocarbon (14C) measurements and inventory data sets. The results show that males and females have similar age trends in CERs, but the gender difference is significant, especially between the ages of 20 and 60, the average CERs was 33% higher for males than for females (P < 0.05). The CO2hr emissions were about 22.2 ± 0.6 kt CO2 per day, which was equivalent to 7.5% of daily CO2ff emissions in winter. The proportion is likely to be twice in summer due to the seasonal fluctuations of fossil fuel emissions. More importantly, the respiratory emissions could increase atmospheric CO2 concentration by about 2 ppm, accounting for 14% ± 6% of average CO2bio concentration in winter. This study highlights the importance of human respiration in carbon emissions in megacities and has implications for a better understanding of the regional carbon budget. Plain Language Summary: Human respiration is an important CO2 source in densely populated areas, and its emission can be estimated by the "bottom‐up" method, just like fossil fuel emissions. However, as a key parameter in the estimate of CO2 emissions from human respiration, the variability of the CO2 emission rate is the main source of uncertainty. Another challenge is how to separate it from other atmospheric CO2 sources, which is related to the estimation of real carbon sources and sinks in natural ecosystems. Taking Beijing as a case study, we combined inventory data sets and radiocarbon (14C) measurements to quantitatively evaluate the contribution of human respiratory emission in a megacity in China, and further isolate the emissions from fossil fuels and biogenic CO2 sources. Although human breathing carbon emissions do not belong to the carbon that can be reduced, ignoring the contribution of human respiration would lead to a corresponding overestimation of carbon emissions from fossil fuel or biogenic sources. This pilot study is helpful to arouse people's attention to human respiratory CO2 emissions and inspire the evaluation method of human respiratory emissions. Key Points: We fully characterized the respiratory CO2 emission rates of Chinese people for the first timeAn approach was developed to quantify the respiratory CO2 concentration in the atmospheric CO2Human respiration should be considered in the regional carbon budget and CO2 monitoring [ABSTRACT FROM AUTHOR]
Titel: |
An Approach for Assessing Human Respiration CO<subscript>2</subscript> Emissions Using Radiocarbon Measurements and Bottom‐Up Data Sets.
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Autor/in / Beteiligte Person: | Wang, Peng ; Zhou, Weijian ; Niu, Zhenchuan ; Huo, Da ; Zhou, Jie ; Li, Haogen ; Cheng, Peng ; Wu, Shugang ; Xiong, Xiaohu ; Chen, Ning |
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Zeitschrift: | Journal of Geophysical Research. Atmospheres, Jg. 129 (2024-05-16), Heft 9, S. 1-11 |
Veröffentlichung: | 2024 |
Medientyp: | academicJournal |
ISSN: | 2169-897X (print) |
DOI: | 10.1029/2023JD040578 |
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