Long-term measurement results of indoor air quality (IAQ) from 1989 to 2013 inside Pit No.1, the largest display hall in Emperor Qin's Terra-cotta Museum (QTM) were used to evaluate the effectiveness of measures for conservation environment improvement of antiques. By comparing the results of sampling campaigns in 2013 with databases in 1989, 2004-2005, 2006-2007, and 2011, seasonal and inter-annual variations in microclimate and aerosol chemical compositions were incorporated in estimating the probable influences of management of surroundings, tourist flow, excavation and restoration task, and renovation and/or new construction work on IAQ in the QTM. Since the implementation of the environmental policies of 1990s, a significant decrease of indoor particulate matter mass for the QTM has been achieved. The mass concentrations of summer TSP decreased from 540.0 μg·m^-3 in 1994 to 172.4 μg·m^-3 in 2004, as well as the winter TSP decreased from 380.0 μg·m^-3 in 1994 to 312.5 μg·m^-3 in 2005. The mass concentration of summer PM_2.5 decreased from 108.4 μg·m^-3 in 2004 to 65.7 μg·m^-3 in 2013, as well as the winter PM_2.5 from 242.3 μg·m^-3 in 2005 to 98.6 μg·m^-3 in 2013. However, it is noted that potential hazards due to the secondary particulate acidic species in indoor air should still be considered to ensure the long-term preservation and conservation of the museum's artifact collection.

aerosol  /  indoor air quality  /  tourism planning  /  environmental policy  /  museum