posted on 2022-01-25, 15:12authored byWei Ma, Yongchun Liu, Yusheng Zhang, Zemin Feng, Junlei Zhan, Chenjie Hua, Li Ma, Yishuo Guo, Ying Zhang, Wenshuo Zhou, Chao Yan, Biwu Chu, Tianzeng Chen, Qingxin Ma, Chunshan Liu, Markku Kulmala, Yujing Mu, Hong He
Since
the 1960s, many indoor and outdoor smog chambers have been
developed worldwide. However, most of them are made of Teflon films,
which have relatively high background contaminations due to the wall
effect. We developed the world’s first medium-size quartz chamber
(10 m3), which is jointed with 32 pieces of 5 mm thick
polished quartz glasses and a stainless-steel frame. Characterizations
show that this chamber exhibits excellent performance in terms of
relative humidity (RH) (2–80%) and temperature (15–30
± 1 °C) control, mixing efficiency of the reactants (6–8
min), light transmittance (>90% above 290 nm), and wall loss of
pollutants.
The wall loss rates of the gas-phase pollutants are on the order of
10–4 min–1 at 298 K under dry
conditions. It is 0.08 h–1 for 100–500 nm
particles, significantly lower than those of Teflon chambers. The
photolysis rate of NO2 (JNO2) is automatically adjustable to simulate the diurnal variation of
solar irradiation from 0 to 0.40 min–1. The inner
surface of the chamber can be repeatedly washed with deionized water,
resulting in low background contaminations. Both experiments (toluene–NOx and α-pinene–ozone systems) and box model
demonstrate that this new quartz chamber can provide high-quality
data for investigating SOA and O3 formation in the atmosphere.