This study investigated the indoor environment of urban and rural elderly residential dwellings in Dalian and Beijing during the heating period in 2017–2018. Each dwelling was assessed for temperature, relative humidity, air pollution and biological pollution, as well as blood pressure parameters related to the health of the elderly. The results showed that the temperature in urban dwellings was higher and more stable than that in rural dwellings, due to the difference in heating devices. Indoor carbon dioxide (CO₂) concentrations in some dwellings exceeded the limit. Indoor formaldehyde and volatile organic compounds (VOC) were lower than the limit values, while urban dwellings had more formaldehyde and total volatile organic compounds (TVOC) pollution than rural dwellings. For rural houses, indoor fuel combustion resulted in higher concentrations of particulate matter below 2.5 microns (PM_2.5) and higher concentrations of carbon monoxide (CO). The biological pollution in rural areas was generally higher than in urban areas. The blood pressure of the elderly in rural areas was higher than that in urban areas, and blood pressure was found to be negatively correlated with room temperature and positively correlated with relative humidity. These results can provide an indicator for the improvement of housing environmental quality for older people in China.

With recent improvements to living standards and renovations to many residential buildings, a large volume of new building materials have been utilized throughout China. Formaldehyde and other kinds of VOC pollutants, such as benzene, toluene and xylene found in new building materials, however, emit gases that may lead to some direct or potential health problems. Bake-out with dilution ventilation technology has the potential to shorten emission cycles of indoor air pollution, by which off-gassing from building materials can be reduced. In this paper, a test chamber was used to represent a newly renovated residential room in China. Experiments were conducted to study the applicability of the technology for removing of formaldehyde, benzene, toluene and xylene. A numerical method was used to simulate a 1 m3-chamber-TVOC removing amount under different operating conditions and the concentration change of TVOC during the bake-out exhaust dilution process. The effects of bake-out temperatures and times, ventilation times, and air change rates on removal are also discussed. Implications: VOCs are the main study objective in this paper. With higher baking temperature, longer baking time and longer ventilation time, the removal efficiency is higher in experiment. Removal content of TVOC increases with the increasing number of ACH. With the consideration of energy consumption, it is more reasonable to choose a ventilation time of 4 hours if ACH is 1.2 times/h.