Study on PM₁₀ Pollution in Central Air Conditioning and Ventilation System and Its Correlation with Air Pollution in Suzhou

Objectives To analyze the pollution status of inhalable particles (PM₁₀)in central air conditioning and ventilation system in Suzhou, and to study its correlation with air pollution.

Methods The study determined concentrations of PM₁₀ in the central air conditioning and ventilation system of 70 public places in Suzhou, and searched concentrations of the major atmospheric pollutants in Suzhou on the day.

Results The total qualified rate of PM₁₀ concentration in the central air conditioning and ventilation system of public places in Suzhou was 62.86% (44/70) and the qualified rate of sampling air outlet was 82.43%(319/387). The qualified rate of air supply outlet of PM₁₀ concentration of the central air conditioning and ventilation systems with the intermediate fresh air filter (89.01%, 162/182) was higher than that of the systems with the primary fresh air filter (76.59%, 157/205), and a statistically significant difference was observed(χ²=10.28, P < 0.01). The average concentration of PM₁₀ in intermediate fresh air filter system was lower than that in primary fresh air filter system, and a statistically significant difference was observed (t=2.41, P < 0.05).There was a positive correlation between concentration of PM₁₀ in air conditioning system and atmospheric PM₁₀ concentration on the day (r_s=0.450, P < 0.01).

Conclusions In 2017—2018, 37.14%(26/70) of public places using central air conditioning and ventilation system in Suzhou was unqualified in PM₁₀ concentration of air supply, which was correlated to outdoor air pollution. The outdoor air pollution should be considered in the design and installation of central air conditioning and ventilation system in large public places and the corresponding requirements for air filter devices should be put forward.