Rapid oxidation of gasoline exhausts reveals marked impacts of transient conditions on potential of secondary organic aerosol production

Abstract Vehicle emission is a major source of atmospheric secondary organic aerosols (SOA). Driving condition is a critical influencing factor for vehicular SOA production, but few studies have revealed SOA production dependence on the rapidly-changing real-world driving conditions. Here, a fast-response oxidation flow reactor system is developed and deployed to quantify the SOA formation potential under transient driving conditions. Results show that the SOA potential varies by orders of magnitude, e.g., 20-1500 mg kg-fuel-1 and 12–155 mg kg-fuel-1 for China V and China VI vehicles, respectively. High speed, acceleration, and deceleration are found to considerably promote SOA production due to higher organic gaseous emissions caused by unburned fuel emission or incomplete combustion. In addition, China VI vehicles significantly reduce SOA potential, yield, and acceleration and deceleration peaks. Our study provides experimental insight into vehicular SOA formation under transient driving conditions, which would benefit high-time-resolved SOA simulations in the urban atmosphere.