Determination of ozone emission from a domestic air cleaner and decay parameters using environmental chamber tests

A methodology has been established to quantify the ozone emission rate from electronic air cleaners, as well as the ozone decay parameter. Three different portable ionisation-type air cleaners were used in the experiments. A stainless steel environmental chamber with volume size 6.4 m3(1.6 x 2 x 2 m) was employed in the study. The leakage rate of the chamber was measured to be 0.0042 h-1by a tracer decay gas test. The ozone growth curve within the chamber was used to quantify the ozone emission rate of the air cleaner and the ozone decay parameter. The emission rate and the decay parameter were determined by the initial slope and the equilibrium state of the growth curve simultaneously, and the technique of least squares fitting was introduced in the data analysis. The ozone emission rates and the decay parameters of Air Cleaner I, II, and III were found to be 119.4 ± 15.6, 77.6 ± 5.4, and 1092.3 ± 112.5 ppb h-1and 2.59 × 10-1± 0.03, 1.68 × 10-2± 0.001 and 9.48 × 10-2± 0.01 h-1, respectively. The wide range of the emission rates was believed to relate to the individual designs of the air cleaners. The variation in decay parameters obtained from the measurements was tentatively associated with the level of VOCs in the sampling environment.