Oxygenated volatile organic compounds are a group of carbon-containing species
that include one or more functional groups. They are formed during oxidation of
hydrocarbons in the atmosphere. Afterwards, they readily undergo atmospheric
processing, which—depending on their chemical properties—can lead to the formation of harmful pollutants, such as ozone or secondary organic aerosols (SOA).
Prolonged exposure to either compound can negatively impact human health.
Unfortunately, most existing analytical techniques struggle to quantify the concentrations of the majority of OVOCs due to their characteristic low abundances and
high reactivities. In addition, most of these compounds are also made up of a complex mixture of isomers that few instruments are able to resolve. Since even slight
changes in structure can impact an OVOC’s atmospheric fate, this can lead to uncertainties when elucidating their chemical mechanisms. As a result, despite decades
of research, there are still many outstanding questions pertaining to atmospheric
processing of OVOCs and, by extension, their impact on air quality.
To combat this issue, novel instrumentation was developed that can provide accurate,
isomer-resolved measurements of a wide variety of OVOCs, which it achieves
by combining the sensitive, specific nature of gas chromatography (GC) with the
equally sensitive, yet non-invasive aspects of chemical ionization mass spectrometry
(CIMS). To showcase its capabilities, these new instrumental methods are applied
to the study of isoprene oxidation. More specifically, we report new insights into
the isomer-specific loss processes of isoprene-derived hydroxy nitrates. Inclusion of
our findings into atmospheric models can greatly improve our simulations of NOx,
ozone, and nitric acid.