Variability in Aromatic Aerosol Yields under Very Low NO Conditions at Different HO/RO Regimes.

Current chemical transport models generally use a constant secondary organic aerosol (SOA) yield to represent SOA formation from aromatic compounds under low NO conditions. However, a wide range of SOA yields (10 to 42%) from -xylene under low NO conditions is observed in this study. The chamber HO/RO ratio is identified as a key factor explaining SOA yield variability: higher SOA yields are observed for runs with a higher HO/RO ratio.

Effects of driving conditions on secondary aerosol formation from a GDI vehicle using an oxidation flow reactor.

A comprehensive study on the effects of photochemical aging on exhaust emissions from a vehicle equipped with a gasoline direct injection engine when operated over seven different driving cycles was assessed using an oxidation flow reactor. Both primary emissions and secondary aerosol production were measured over the Federal Test Procedure (FTP), LA92, New European Driving Cycle (NEDC), US06, and the Highway Fuel Economy Test (HWFET), as well as over two real-world cycles developed by the California Department of Transportation (Caltrans) mimicking typical highway driving conditions. We showed that the emissions of primary particles were largely depended on cold-start conditions and acceleration events.

Comprehensive analysis of the air quality impacts of switching a marine vessel from diesel fuel to natural gas.

New environmental regulations are mandating cleaner fuels and lower emissions from all maritime operations. Natural gas (NG) is a fuel that enables mariners to meet regulations; however, emissions data from maritime operations with natural gas is limited. We measured emissions of criteria, toxic and greenhouse pollutants from a dual-fuel marine engine running either on diesel fuel or NG as well as engine activity and analyzed the impacts on pollutants, health, and climate change.