OH- and O3-initiated atmospheric degradation of camphene: product yields and mechanisms.

MARÍA BELÉN BLANCO; ELIZABETH GAONA COLMAN; MARIANO TERUEL; IAN BARNES

Conferencia; Atmospheric Chemical Mechanisms 2016; 2016

Camphene (2,2-dimethyl-3-methylenebicyclo[2.2.1]heptane) is a bicyclic monoterpene, which is emitted to the atmosphere by vegetation. It is one of the most abundant monoterpene emitted from plants such as Pinus sylvestris, Abies alba and Echinacea species.Once in the atmosphere, this monoterpene reacts with trace oxidants (OH and NO3 radicals, and O3 molecules) leading to the formation of wide variety of oxygenated compounds and secondary organic aerosol (SOA). In this sense, product studies have been performed at (298 ± 2) K and 760 Torr of synthetic air for the OH reactions in the absence and presence of NOx, and for O3 molecules at (298 ± 2) K and 750 Torr of synthetic air. The experiments were performed in an atmospheric chamber coupled with a FTIR spectroscopy. For OH reaction the obtained molar products yields were: acetone (10 ± 2) % and (33 ± 6) %, and formaldehyde (3.6 ± 0.7) % and (10 ± 2) % in the absence and presence of NOx, respectively. Formaldehyde was the unique product quantified due to O3 reaction obtaining a yield of (29 ± 6) %. Taking into account that monoterpenes are the main emitted biogenic compounds together with isoprene, a well-established experimental study of their atmospheric reaction pathways are fundamental for assessing the oxidative capacity of the atmosphere and SOA formation