Quantitative evidence highlights the drivers on highly photochemically active VOC sources

Abstract Ground-level ozone pollution has become a critical air quality issue. VOCs (Volatile organic compounds), as the precursors of ozone, have complicated photochemical reaction mechanisms. The quantitative analysis of VOCs’ photochemical reaction potential and the influence of driving factors (e.g. molecular properties), are less understood. Here, we first established a reactivity equivalent (reactE) evaluation system and constructed two functions to thoroughly explore the impact of different factors on the reactE. The results demonstrated that alkenes, especially isoprene, have higher reactE values (reactE=68.06) and exhibit more fluctuations during different periods, which reflected that high-reactE species are more sensitive to the driving factors. We further integrated the reactE evaluation system with a source receptor model, and quantified the reactE of VOCs sources. The results showed that industrial emission, among anthropogenic emission sources, has the highest reactE of 70, followed by solvent usage (reactE=43). This study provided the support that controlling the high reactE species in key time (when the species reactE is more sensitive to the environment) is necessary.