Removal Efficiency of Indoor VOC_S by Ozone Air Cleaner

摘要

The aggravation of indoor air quality is related to the long-term accumulation of volatile organic compounds(VOC_S)in indoor environment.Indoor VOC_S are known to cause adverse effects on human health including carcinogenic and noncarcinogenic effects.Indoor VOC_S come from outdoor sources,such as combustion,cooking,building materials,furniture,and biological sources.Indoor VOC_S include n-alkanes,branched alkanes,alkenes and cycloalkanes,halogen derivatives,alcohols,ethers,aldehydes,ketones,nitrogen compounds,aromatics,and terpenes.Ozone air cleaners have been claimed to remove VOC_S in indoor environment.In this study,we measured the ozone emission rate and tested the operation characteristics of seven selected ozone air cleaners in a stainless steel environmental test chamber(dimension:2.2(L)×2.2(W)×2.3(H)m)that simulate indoor environment.Two types of ozone air cleaner including negative ionic ozone air cleaner,and photo-start ozone air cleaner,were tested under airtight condition,with the temperature around 23-26 deg C and the relative humidity in the range of 55-65%.An emission-decay mass balance model was applied to fit the concentration profile observed from experimental results,and the maximum ozone concentration,C_(max),ozone emission rate,E,and the ozone decay constant,kd,were obtained from the regression of the experimental result for each ozone air cleaner.The C_(max)in the environmental test chamber ranges from 2224 to 215 ppb;E is between 1.55 and 5.34(mg/h);kd is between 0.069 and 1.18(h~(-1)).The VOC_S decay experiments were performed in a small-scale environmental chamber(dimension:0.45(L)× 0.4(W)× 0.4(H)m)under different environmental conditions.The decay constant and CADR of VOC_S increase with temperature but don't show significant relations with relative humidity.The increase of the air flow rate can increase the VOC_S decay rate effectively.In the presence of ozone,adding á-pinene can generate OH radical,which can enhance the VOC_S decay rate and CADR.