Development of a multimedia model (IIAQ-CC) to assess climate change influences on volatile and semi-volatile organic compounds in indoor environments

An indoor air quality model (IIAQ-CC) was developed to assess climate change (CC) influences on indoor level of volatile or semi-volatile organic compounds. With IIAQ-CC, the CC influences is predicted in integrated manners by factors including fate/transport properties of pollutants, building characteristics, occupant behaviors, indoor emission sources, and outdoor air quality. IIAQ-CC was evaluated for the temperature sensitivity of indoor formaldehyde (FA) concentration at outdoor temperature below 20 °C. No significant difference (t-test, p < 0.05) was found between the predicted (3.9 ± 1.0%/oC) and the measured (5.0%/oC with a 95% confidence interval (3.7%/oC to 6.4%/oC)), demonstrating that IIAQ-CC can successfully predict CC influences driven by temperature change on VOCs of indoor environmental concern. IIAQ-CC predicts that the long-term FA concentration may slowly rise due to increase in the outdoor concentration or may decrease in the presence of strong indoor sources in RCP8.5 conditions of South Korea. In either case, the long-term change does not exceed 12% of the average FA concentration of the base period. Over a shorter period (e.g., a month), the FA level may noticeably rise (by about 4 times) when windows are closed due to exceedingly hot or cold weather. The FA concentration change is primarily governed by duration of windows kept open, which depends on outdoor temperature. That is, temperature manifests its effects on the indoor air quality essentially by change in window opening behavior rather than by changes in kinetics or equilibrium processes such as photo-degradation and sorption/desorption onto/from walls and floor.