Oxidation Flow Reactor for Simulating and Accelerating Atmospheric Secondary Aerosol Formation

Oxidation flow reactors (OFRs) is widely employed in both atmospheric chemistry and physic studies, it’s used to simulate and accelerate the formation of secondary organic aerosols (SOAs), that constituted the major fraction of PM2.5. The SOA is formed by complex gas-phase and heterogeneous oxidation reactions between volatile organic compounds (VOCs) emitted from natural and anthropogenic sources and atmospheric oxidants like ozone O3 and OH radicals. OFR simulates atmospheric environment processes such as photochemistry by exposing VOCs to a combination of oxidizing agents such as nitrate radical NO3, ozone O3, and hydroxyl radicals OH and sometimes using also ultraviolet radiation to simulate pollutants transformation under solar radiation. This promotes the formation of highly oxidized organic molecules with low volatility, which can condense in the particulate (solid) phase contributing to SOA particle formation and growth. The advantage of OFRs facing other tools like environmental chambers is their ability to precisely control reaction parameters such as temperature, humidity, and reactant concentrations, allowing systematic studies of SOA formation under a long range of conditions. In addition, OFRs can be used to study the contributions of different VOC sources to SOA formation and to evaluate the effectiveness of mitigation strategies aimed at reducing SOA emissions. The results obtained from OFR experiments can be compared with field measurements to improve our understanding of the processes that govern SOA formation in the atmosphere.