Long-term concentrations of volatile organic compounds in a new apartment in Beijing, China

To investigate the long-term volatile organic compound (VOC) concentration-time behavior in real buildings, field measurements were conducted in a newly built apartment in Beijing. Measurements were made periodically during the following eighteen months after the interior construction was completed. VOC concentrations were extremely high immediately after the interior construction. Indoor VOC concentrations did not decay all the time: there was a clear downward trend during the first few months, after which the pattern differed. A greater variety of VOCs and generally higher concentrations were observed in summer than in winter. Patterns of variations were different for VOCs from building materials compared to VOCs from human-related activities. For some VOCs, the concentrations in summer could be 2-10 times as much as those in winter. These large concentration increases could be mainly due to the increased emission rates of building materials at elevated indoor temperature, and decreased air infiltration rate as another factor. In practice, attentions should be paid to the situation when indoor temperature is high and ventilation rate is low. Measurements conducted under different environmental conditions should be used in caution when extending the results to a different time or indoor conditions.