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摘要
In indoor environments, accretion of mass to materials may provide sites for surface chemistry that differ from those of the original material. Since indoor surfaces are a major sink of oxidant gases, surface mass accretion may impact indoor O-3 chemistry. In this study, the effect of surface mass accretion on O-3 surface deposition was tested by deploying cleaned borosilicate glass plates in two types of indoor environments: a mechanically ventilated (MV) office and a naturally ventilated (NV) residence located in Singapore. In each environment, seven replicate glass plates and one field blank were deployed for between 7 and 56 days and examined in a laboratory chamber for O-3 deposition rate and surface reaction probability. Average mass accretion to plates, deployed in a horizontal position and including deposited particles, was 10.6 mg/(m(2)d) in the MV office vs. 18.5 mg/(m(2)d) in the NV residence and the comparison is at the threshold of statistical significance (p = 0.054). Ozone reactivity to the plates increased in magnitude and persistence with longer plate deployment. Ozone reaction probabilities to cleaned plates prior to deployment ranged [0.06-0.74] x 10(-6) for two hours of observable removal whereas plates deployed for 56 days ranged [0.15-1.2] x 10(-6) for four hours of observable removal. Regressions of cumulative O-3 removed during chamber tests vs. mass accreted show removal of 4.3 nmol O-3 /mg for the NV residence and 2.4 nmol O-3/mg for the MV office. These results imply that accretion of mass to surfaces may alter indoor O-3 transformation pathways.
- 出版日期2018-6-15
