Objective To investigate the air quality in a large shopping mall, and identify change patterns and possible influencing factors.
Methods The air quality of a shopping mall in Beijing was monitored in 2013. Two shopping areas and one dining area were selected as monitoring spots. The data of temperature, humidity, inhalable particular matter (PM10), formaldehyde, carbon monoxide (CO), carbon dioxide (CO2) were collected once an hour by remote transmission technology for analysis.
Results The qualified rate of CO2was the highest (100%), followed by temperature (98.82%), PM10 (96.81%), CO (84.73%), formaldehyde (69.41%), and humidity (29.36%). Humidity showed evidently seasonal variations (P < 0.05). There were positive correlations between indoor and outdoor PM10 concentrations (r=0.681, P < 0.05) and between indoor PM10 concentrations and passengers flow (r=0.162) (P < 0.05). The concentrations of CO and CO2in the dining area were higher than the other two monitoring spots, and the time sessions with higher concentration were matched with the peak time sessions of dinning. The concentrations of formaldehyde were significantly varied by monitoring spots (P < 0.05), and showed great fluctuations over time (peak value, 0.214 mg/m3) and a positive correlation with humidity (r=0.740, P < 0.05).
Conclusion The main hazardous factors of the air quality in the shopping mall include PM10, CO, and formaldehyde. Indoor PM10 concentrations are mainly affected by outdoor PM10 concentrations and passengers flow. Catering activities are the main source of CO pollution, while higher passengers flow would also increase CO concentrations in an indirect way. Partial decoration and high humidity potentially contribute to the persistent pollution of formaldehyde. Therefore, the shopping mall should take such actions as running central air conditioning systems by areas or timely adjusting fresh air volume to improve the air quality.
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