Natural sources exert substantially greater influence on atmospheric ozone formation during high-ozone episodes in a...

Atmospheric ozone (O₃) formation mechanisms remain challenging to clarify through conventional approaches that rely on the observed or initial volatile organic compound (VOC) concentration data, as they fail to capture the dynamic photochemical consumption processes. This study presents a novel consumption-based methodology that quantifies photochemically consumed VOCs and their critical sources during the O₃ formation, providing unprecedented insights into the pollution mechanisms. Through systematic analysis of 17 typical high O₃ episodes in 2020 in Zhumadian, China, the results showed that the photochemical losses of alkenes had the most substantial impact on the O₃ formation, with a contribution of ∼94.9 % to the total O₃ formation potential (OFP) of the consumed VOCs. The losses and OFP values of isoprene and ethylene, which are primarily derived from biogenic and combustion emissions, respectively, were markedly higher than those of any other VOC species. Biogenic emissions (∼55.8 %) and combustion emissions (∼16.8 %) were the primary contributing sources to the consumed VOCs during these O₃ episodes. The OFP of the consumed VOCs derived from biogenic emissions (47.3 %) and combustion emissions (27.6 %) contributed the highest to the total OFP of the consumed VOCs derived from all the emission sources. Therefore, natural sources could exert clearly greater impacts on atmospheric O₃ formation during the high O₃ episodes. These findings provide a transformative understanding of O₃ formation kinetics and establish a new paradigm for urban air quality management that must account for biogenic-anthropogenic interactions.