Potential Impact of Battery Electric Vehicle Penetration and Changes in Upstream Process Emissions Assuming Night‐Charging on Summer O 3 Concentrations in Japan

A regional meteorology–chemistry model was used to evaluate the impact of battery electric vehicles (BEV) penetration on summer O 3 concentrations in Kanto (Japan's most populous region). When all passenger cars shifted to BEVs, daytime ozone (O 3 ) concentrations decreased over a wide area. The reduction of vehicle exhaust reduced O 3 in inland suburban areas (NO x ‐limited) and the reduction of gasoline fuel evaporation from vehicles and gas stations reduced O 3 in urban areas (volatile organic compound (VOC)‐limited). The maximum location of maximum daily 8‐hr average O 3 (MDA8hO 3 ) sensitivity (−5%; −5 ppb) was at midway between urban and suburban areas, to which the reduction of exhaust and fuel evaporation contributed equally, respectively. The additional emissions from thermal power plants due to BEV's night‐charging could cause up to ±5% sensitivity to next‐day surface O 3 concentrations topically. Depending on the O 3 sensitivity regime (NO x ‐ or VOC‐limited), additional NO x ‐rich plumes from rural (urban) power plants tended to increase (decrease) the next day's O 3 . However, the spatial distribution of the regime varies temporally depending on such as NO x /VOC emission ratios and meteorological conditions. This study indicated that the distribution of negative (positive) O 3 sensitivity by NO x ‐rich plume is consistent with that of small (large) H 2 O 2 /HNO 3 concentration ratios, indicating that H 2 O 2 /HNO 3 works well as an indicator to discriminate O 3 sensitivity regimes. Utilization of the H 2 O 2 /HNO 3 indicator would enable regime distribution predictions without sensitivity simulations with varying NO x and VOC emissions, which would contribute to reducing computational costs. Ozone (O 3 ), which causes respiratory health effects, is formed in the atmosphere by its precursors NO x and volatile organic compound (VOC). Conventional gasoline vehicle exhaust is a major source of NO x and VOC, gasoline fuel VOC evaporate from vehicles and gas stations and thermal power plants emit mainly NO x . This study evaluated the impact of BEV penetration on summer O 3 concentrations in Kanto using numerical simulation. When all passenger cars shifted to BEVs, daytime O 3 concentrations decreased over a wide area in Kanto (up to −5%). The additional emissions from thermal power plants due to BEV night‐charging had a ±5% impact on next‐day O 3 concentration topically. O 3 has a NO x ‐ or VOC‐sensitive region (called O 3 sensitivity regime), and