Air pollutants impacted by different purification methods of subway air conditioning and ventilation system

ObjectiveTo investigate the influence of different purification methods on air supply pollution of air conditioning ventilation system in Shanghai rail transit system, then to provide suggestions for improving the air quality of subway.

MethodsAs the air conditioning and ventilation system in the public area of stage 2 and 3 construction stations in Shanghai subway route has two different purification methods, 50% of the stations of the same type were selected in stage 2 and 3 respectively in this test, and measured the levels of airborne particulate matter, bacteria and fungi of air conditioning ventilation system, in the same ventilation mode.

ResultsThe levels of air supply pollutants by air conditioning ventilation system of new subway is lower than that of hygienic standard (P < 0.05).However, the results showed that the level of air conditioning pollution in stage 2 is higher than that in stage 3, and the average concentrations of bacteria, fungi and airborne particulate matter were 1.48 times, 1.74 times and 1.21 times respectively (P < 0.05).Moreover, the concentration of bacteria, fungi on the surface of a particle(≥2μm) in stage 2 were 1.64 times and 2.01 times respectively higher than that in stage 3 (P < 0.05), but concentrations of bacteria, fungi on the surface of a particle(< 2μm) with no significant difference (P>0.05).

ConclusionAdding an electronic air purifying disinfection device can effectively reduce the levels of airborne particulate matter, bacteria and fungi, on the basis of a primary filter in air conditioning and ventilation system of the subway system.