Anthropogenic particulate matter (PM) emissions from the transport sector are a major contributor to global air pollution and associated adverse health effects. While the health impacts of PM are well-documented, the specific chemical and physical properties driving its toxicity, such as oxidative potential (OP) remain poorly understood and quantified. This study investigates the OP activity of PM emissions from a small jet engine combustion chamber (using JP-8 fuel) and a marine diesel engine (using low sulfur Heavy Fuel Oil, LS-HFO, and Marine Gas Oil, MGO) under fresh and photochemically aged conditions. Using a novel online instrument the Online Oxidative Potential Ascorbic Acid Instrument (OOPAAI)—we quantified in real-time OP activity of PM. Fresh emissions were sampled directly, while the aged emissions were processed in a photochemical reactor to simulate atmospheric ageing for 1 to 12 equivalent days. Our results illustrate that mass-normalized OP activity showed no significant change with particle ageing for ship emissions but increased substantially for aircraft emissions. The average chemical composition of PM, characterized by average O/C and H/C ratios of the organic mass fraction, indicated increasing oxidation with ageing, correlating well with higher OP activity of aircraft emissions. These findings highlight the importance of considering both fresh and aged emissions in assessing the health impacts of PM emission from fossil fuel sources, as atmospheric processing can drastically alter their oxidative properties.     «

Anthropogenic particulate matter (PM) emissions from the transport sector are a major contributor to global air pollution and associated adverse health effects. While the health impacts of PM are well-documented, the specific chemical and physical properties driving its toxicity, such as oxidative potential (OP) remain poorly understood and quantified. This study investigates the OP activity of PM emissions from a small jet engine combustion chamber (using JP-8 fuel) and a marine diesel engine (...     »