The Influence of Centralized Air Ventilation System on PM₁₀ Concentration in Public Places

Objective To explore the influence of centralized air ventilation system (CAVS) on the concentration of PM₁₀ in the indoor air of public places.

Methods The basic data of 11 public places with CAVS selected as monitoring sites and 6 institutions without CAVS selected as control sites were collected by questionnaire during wintertime in 2015. EVM-3 dust detector was used to test the concentration of indoor PM₁₀in 1 minute at all selected sites. A nonparametric test was used to analyze the influence of CAVS on the concentration of indoor air PM₁₀.

Results The use of CAVS could help reducing indoor PM₁₀ level (Mann-Whitney U test, P=0.023). The efficiency on indoor air PM₁₀ was decreased with extending the length of cleaning CAVS (Z=13.155, P=0.004). Compared with primary filter, medium efficiency filter could play a better role on reducing indoor PM₁₀ level(Z=-3.346, P=0.001). Increasing the frequency of cleaning fresh air inlet filter could improve the effect of reducing indoor PM₁₀ concentration (Z=11.891, P=0.018); cleaning monthly might be the best choice.

Conclusion Reasonable use of CAVS, regular cleaning, applying higher level filter and keeping better cleaning frequency could effectively reduce the indoor PM₁₀ level and improve indoor air quality to safeguard public health.