Simulation Chamber and Container Measurements

VOC emissions from three Norwegian spruce trees P. abies L. Karst) kept in 50 L containers for 6 months prior to laboratory measurements were investigated in response to changes in temperature over a small range of values from 23°C to 35°C in approximate steps of 4°C at a fixed light intensity of 200 xmol photons m s by Filella et al. [186]. It 

G6mez Alvarez et al. coupled PTR-MS with the European PHOtoREactor (EUPHORE) atmospheric simulation chamber (Valencia, Spain) to provide experimental confirmation of the dicarbonylic mechanism in the photooxidation of toluene and benzene [189]. The particular benefit of PTR-MS in this context is its relatively fast response time, which provides data that can be tested against a Master Chemical Mechanism (MCMv3.1) model. Differences in mass spectral fragmentation patterns also allowed PTR-MS to distinguish between cis- and fraws-butenedial, which are two of the products resulting from the photooxidation process. 

Laboratory chamber studies utilizing PTR-MS for VOC measurements have also been used to elucidate the chemical routes for the formation of secondary organic aerosols [191-197]. An example is aerosol formation from the 1,3,5-trimethylbenzene-propene-NO c-water vapour system, which was investigated at the PSI smog chamber [ 192,196]. This work classified the VOCs according to their temporal profile and identified oligimerization as a key secondary organic aerosol formation mechanism. 

A cuvette system is a sealed chamber, for example, made from Teflon or glass, within which air circulates with incoming and outgoing gas streams. 

Chamber (Caltech Indoor Chamber Facility) experiments have also been carried out by Lee et al. to monitor the time evolution and yields of gas-phase VOCs produced by the ozonolysis of ten different terpenes [197] six monoterpenes (a-pinene, (3-pinene, 3-carene, terpinolene, a-terpinene and myrcene), two sesquiterpenes (a-humulene and p-caryophyllene) and two oxygenated terpenes (methyl chavicol and linalool). Several gas-phase oxidation products were identified including formaldehyde, acetaldehyde, formic acid, acetone, acetic acid, nopinone and pinonaldehyde. 

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