Anthropogenic CO₂ Emissions Changes in an Urban Area of Tokyo, Japan, Due to the COVID‐19 Pandemic: A Case Study During the State of Emergency in April–May 2020

The influence of the COVID‐19 pandemic on urban CO 2 emissions was investigated using atmospheric observations in the residential area (approximately 4 × 10 5 m 2 ) in Tokyo, Japan. The measured CO 2 flux decreased by 20% ± 3% in April–May 2020 compared to the same period during the past few years. The exchange ratio of O 2 and CO 2 revealed the breakdown of emission sources; the decrease of flux was due to the decrease in liquid fuel consumption, while household gas fuel consumption was slightly increased; this was also supported by the simultaneously measured CO:CO 2 concentration ratio. A human‐activity analysis in the flux footprint area supported the results of the observation; car traffic decreased and household gas consumption increased.