Human metabolic emissions of carbon dioxide and methane and their implications for carbon emissions.
Mengze Li, Gabriel Bekö, Nora Zannoni, Giovanni Pugliese, Mariana Carrito, Nicoletta Cera, Catarina Moura, Pawel Wargocki, Priscila Vasconcelos, Pedro Nobre, Nijing Wang, Lisa Ernle, Jonathan Williams
Author Information
Mengze Li: Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany; Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, USA. Electronic address: mengze.li@mpic.de.
Gabriel Bekö: International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Lyngby 2800, Denmark; Department of Architecture, College of Architecture, Art and Design, Ajman University, Ajman, P.O. Box 346, United Arab Emirates.
Nora Zannoni: Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
Giovanni Pugliese: Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany; Department of Anaesthesia and Intensive Care, Rostock University Medical Center, Schillingallee 35, 18057 Rostock, Germany.
Mariana Carrito: Center for Psychology at University of Porto (CPUP), Faculty of Psychology and Education Sciences, University of Porto, Porto, Portugal.
Nicoletta Cera: Center for Psychology at University of Porto (CPUP), Faculty of Psychology and Education Sciences, University of Porto, Porto, Portugal; Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Coimbra, Portugal.
Catarina Moura: Center for Psychology at University of Porto (CPUP), Faculty of Psychology and Education Sciences, University of Porto, Porto, Portugal.
Pawel Wargocki: International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Lyngby 2800, Denmark.
Priscila Vasconcelos: Center for Psychology at University of Porto (CPUP), Faculty of Psychology and Education Sciences, University of Porto, Porto, Portugal.
Pedro Nobre: Center for Psychology at University of Porto (CPUP), Faculty of Psychology and Education Sciences, University of Porto, Porto, Portugal.
Nijing Wang: Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
Lisa Ernle: Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
Jonathan Williams: Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany. Electronic address: jonathan.williams@mpic.de.
Carbon dioxide (CO) and methane (CH) are important greenhouse gases in the atmosphere and have large impacts on Earth's radiative forcing and climate. Their natural and anthropogenic emissions have often been in focus, while the role of human metabolic emissions has received less attention. In this study, exhaled, dermal and whole-body CO and CH emission rates from a total of 20 volunteers were quantified under various controlled environmental conditions in a climate chamber. The whole-body CO emissions increased with temperature. Individual differences were the most important factor for the whole-body CH emissions. Dermal emissions of CO and CH only contributed ~3.5% and ~5.5% to the whole-body emissions, respectively. Breath measurements conducted on 24 volunteers in a companion study identified one third of the volunteers as CH producers (exhaled CH exceeded 1 ppm above ambient level). The exhaled CH emission rate of these CH producers (4.03 ± 0.71 mg/h/person, mean ± one standard deviation) was ten times higher than that of the rest of the volunteers (non-CH producers; 0.41 ± 0.45 mg/h/person). With increasing global population and the expected large reduction in global anthropogenic carbon emissions in the next decades, metabolic emissions of CH (although not CO) from humans may play an increasing role in regional and global carbon budgets.
