Investigation of the reaction of ozone with isoprene, methacrolein and methyl vinyl ketone using the HELIOS Chamber
The rate constants for the ozonolysis of isoprene (ISO), methacrolein (MACR) and methyl vinyl ketone (MVK) have been measured using the newly built large volume atmospheric simulation chamber at CNRS-Orleans (France), HELIOS (cHambrE de simuLation atmosphérique à Irradiation naturelle d’OrléanS). The OH radical yields from the ozonolysis of isoprene, MACR and MVK have been also determined as well as the gas phase stable products and their yields. The secondary organic aerosol yield for the ozonolysis of isoprene has been tentatively measured in presence and absence of OH radicals scavenger. The measurements have been performed under different experimental conditions with and without adding cyclohexane (cHX) as OH radical scavenger. All experiments have been conducted at 760 torr of purified dry air (RH ≈ 2.5%) and ambient temperature (T = 281-295 K). The data obtained are discussed and compared with those from the literature. The use of the HELIOS facility and its associated analytical equipment enables to derive kinetic parameters as well as mechanistic information in near realistic atmospheric conditions.