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Atmospheric Oxygen (O2) is one of the dominating features that allow the earth to be a habitable planet with ad-vanced civilization and diverse biology. However, since the late 1980s, observational data have indicated a steady de-cline in O2 content on the scale of parts-per-million level. The current scientific consensus is that the decline iscaused by the fossil-fuel combustion; however, few works have been done to quantitatively evaluate the response of O2 cycle under the anthropogenic impact, at both the global and regional scales. This paper manages to quantify theland O2 flux and makes the initial step to quantificationally describe the anthropogenic impacts on the global O2budget. Our estimation reveals that the global O2 consumption has experienced an increase from 33.69 ± 1.11 to47.63 ± 0.80 Gt (gigaton, 109 t) O2 yr-1 between 2000 and 2018, while the land production of O2 (totaling 11.34 ±13.48 Gt O2 yr-1 averaged over the same period) increased only slightly. In 2018, the combustion of fossil-fuel andindustrial activities (38.45 ± 0.61 Gt O2 yr-1) contributed the most to consumption, followed by wildfires (4.97 ± 0.48Gt O2 yr-1) as well as livestock and human respiration processes (2.48 ± 0.16 and 1.73 ± 0.13 Gt O2 yr-1, respect-ively). Bing of fossil-fuel that causes large O2 fluxes occurs in East Asia, India, North America, and Europe, whilewildfires that cause large fluxes in comparable magnitude are mainly distributed in central Africa.