A Smog Chamber Facility for Qualitative and Quantitative Study on Atmospheric Chemistry and Secondary Organic Aerosol

Abstract

In order to investigate the atmospheric oxidation processes and the formation of secondary organic aerosol (SOA), an indoor environmental reaction smog chamber are constructed and characterized. The system consists of the collapsible ∼830 L FEP Teflon film main reactor, in which the atmospheric chemical reactions take place and the formation of SOA occurs under the simulated atmospheric conditions, and the diverse on-line gas-and particle-phase instrumentation, such as the proton transfer reaction mass spectrometer, the synchrotron radiation photoionization mass spectrometer, the aerosol laser time-of-flight mass spectrometer, and other traditional commercial instruments. The initial characterization experiments are described, concerning the temperature and ultraviolet light intensity, the reactivity of the pure air, the wall loss rates of gaseous compounds and particulate matter. And the initial evaluation experiments for SOA yields from the ozonolysis of α-pinene and for mass spectra of the products resulting from the photooxidation of OH initiated isoprene are also presented, which indicate the applicability of this facility on the studies of gas-phase chemical mechanisms as well as the formation of SOA expected in the atmosphere.

Characterization of a Smog Chamber for Studying Formation and Physicochemical Properties of Secondary Organic Aerosol

“…The concentration of α-pinene and toluene remained at 75.55 ± 0.83 ppb, and 91.76 ± 0.82 ppb, respectively. Also negligible wall loss for organics has been reported in Wang et al (2014) and Hu et al (2014). The wall loss constants are in agreement with those of other chambers in Table 3.…”

“…After 5 hr of O 3 injection at 218 ppb, total particle concentration was ~10 particles cm -3 in number and ~0.20 µg m -3 in mass, respectively. These are comparable with those of Hu et al (2014). In second experiment, ~200 ppb each of NO, NO 2 and H 2 O 2 were injected and UV light was used to irradiate the reaction mixture.…”

“…Density of aerosol equivalent to 1 g cm -3 was assumed for the evaluation of SOA mass concentrations. A comparison of yield data with other studies (Griffin et al, 1999;Cocker et al, 2001a;Saathoff et al, 2008;Wang et al, 2014;Hu et al, 2014) is shown in Fig. 11.…”

“…The yield data for dark α-pinene ozonolysis is readily available in literature (Griffin et al, 1999;Cocker et al, 2001a;Saathoff et al, 2008;Wang et al, 2014;Hu et al, 2014). The initial conditions and yield for each ozonolysis experiment are presented in Table 4.…”

“…In SOA researches, smog chambers have been proved as a potent tool (Odum et al, 1996;Kleindienst et al, 1999;Cocker et al, 2001b;Takekawa et al, 2003;Paulsen et al, 2005;Carter et al, 2005;Hu et al, 2014;Wang et al, 2014). Availability of natural sunlight is one of the main advantages in outdoor chambers.…”