Researchers from UC Riverside will continue systematic laboratory based investigations of the oxidation pathways of the alkane and alkene fractions of the non-methane hydrocarbons (NMHC) arising from natural and anthropogenic sources and found in urban and remote tropospheric air. The alkane fraction in particular constitutes the largest known mass fraction of NMHC present in urban atmospheres. However, these compounds exhibit a lower general reactivity with key atmospheric oxidants such as OH, NOx and ozone and their oxidative conversation to secondary organic aerosols (SOA) has been less comprehensively studied than more reactive compounds such as isoprene and aromatics. SOA, resulting from the condensation of low vapor pressure reaction products of NMHCs and volatile organic compounds (VOCs), are a key factor in our understanding the chemistry, physiology and epidemiology of the fine particulate matter (PM 2.5; particulate matter less than 2.5 microns in diameter) implicated in the health impacts of atmospheric aerosols. SOA also have effects on visibility and global climate.
