Abstract
Abstract. We describe here characterization of a new state-of-the-art smog chamber facility for studying atmospheric gas-phase and aerosol chemistry. The chamber consists of a 30 m3 fluorinated ethylene propylene (FEP) Teflon film reactor housed in a temperature-controlled enclosure equipped with black lamps as the light source. Temperature can be set in the range from −10 to 40 °C at accuracy of ±1 °C as measured by eight temperature sensors inside the enclosure and one just inside the reactor. Matrix air can be purified with non-methane hydrocarbons (NMHCs) < 0.5 ppb, NOx/O3/carbonyls < 1 ppb and particles < 1 cm−3. The photolysis rate of NO2 is adjustable between 0 and 0.49 min−1. At 298 K under dry conditions, the average wall loss rates of NO, NO2 and O3 were measured to be 1.41 × 10−4 min−1, 1.39 × 10−4 min−1 and 1.31 × 10−4 min−1, respectively, and the particle number wall loss rate was measured to be 0.17 h−1. Auxiliary mechanisms of this chamber are determined and included in the Master Chemical Mechanism to evaluate and model propene–NOx–air irradiation experiments. The results indicate that this new smog chamber can provide high-quality data for mechanism evaluation. Results of α-pinene dark ozonolysis experiments revealed secondary organic aerosol (SOA) yields comparable to those from other chamber studies, and the two-product model gives a good fit for the yield data obtained in this work. Characterization experiments demonstrate that our Guangzhou Institute of Geochemistry, Chinese Academy Sciences (GIG-CAS), smog chamber facility can be used to provide valuable data for gas-phase chemistry and secondary aerosol formation.
Highlights
Smog chambers provide a controlled environment to study the formation and the evolution of specific compounds of interest by isolating the influence of emissions, meteorology and mixing effects
In the mid-1980s, Seinfeld and colleagues at the California Institute of Technology in Pasadena developed a 65 m3 outdoor chamber made of fluorinated ethylene propylene (FEP) Teflon film to study the aerosol formation from gas-phase precursors such as aromatic and biogenic hydrocarbons (Leone et al, 1985; Stern et al, 1987)
Compressed indoor air is forced through a combustion chamber filled with Hopcalite and a series of bed scrubbers containing activated charcoal, Purafil, Hopcalite and allochroic silica gel, followed by a PTFE filter to provide this source of purified air with a maximum flow rate of 200 L min−1
Summary
Smog chambers provide a controlled environment to study the formation and the evolution of specific compounds of interest by isolating the influence of emissions, meteorology and mixing effects. Larger volume allows experiments of longer durations to be conducted and more instruments to be used Considering these concerns, Tobias and Ziemann (1999) used a 7000 L Teflon environmental chamber to generate organic aerosols through gas-phase reactions of 1-tetradecene and ozone. This paper describes a new state-of-the-art indoor smog chamber facility established at the Guangzhou Institute of Geochemistry, Chinese Academy Sciences (GIG-CAS) This GIG-CAS chamber facility is designed to study formation mechanisms of ozone and SOA as well as the evolution of SOA; to evaluate the mechanisms, under lowNOx and VOC conditions; and to serve as a platform for evaluating the performance of newly developed gas or particle monitors. A series of initial characterization experiments have been carried out and are discussed in this paper
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