Experimental Study on PM2.5 Purification Characteristics of Different Filter Units in Enclosed Environments

Many epidemiological studies have shown that long-term exposure to high PM2.5 concentrations can significantly increase the morbidity and mortality of different diseases. Air cleaners are effective in removing PM2.5. In the present research, different filter units were tested to determine their PM2.5 filtration efficiency. The filter face velocity was adjusted to 50%, 75%, 100%, 125%, and 150% of the corresponding rated airflow. The single-pass efficiencies, resistances, and cleaning efficiencies were simultaneously measured on every filter. In order to determine the clean air delivery rate (CADR) and cleaning energy efficiency (CEE) of different filter units, we designed a specific air cleaner that can replace different filter units in the test chamber. Our results showed that different filter units can effectively remove PM2.5. The filtration efficiencies of electrostatic structure precipitators (ESP) and intense field dielectric (IFD) were close those of the sub-high efficiency glass fiber filter. In this case, filtration efficiency decreased when wind speed increased, whereas that of the fiber filter did not. Even when cleaners with different filter units were able to quickly remove fine particles, the highest CADR and CEE values were obtained when the IFD cleaner was used. In contrast, medium efficiency glass fiber cleaners displayed the smallest CADR and CEE values. The CADR and CEE values of the medium efficiency glass fiber cleaner were about 48.3% and 51.4% that of the IFD cleaner. The present study provides relevant data that will be useful in pandemic prevention and control in order to reduce the risk of infection in enclosed environments.