Residential lifetime exposure risk of formaldehyde in residential buildings in Hong Kong

Formaldehyde (HCHO) is a carcinogenic toxicant commonly presented in indoor air and can impose long-term health hazards to building occupants. In this study, the exposure risk of HCHO in residential homes of Hong Kong was evaluated in terms of the expected loss of life expectancy (LLE). In particular, home staying time distribution patterns generated from reported home activity patterns using Monte-Carlo simulations were used to evaluate the cumulative exposure for residence at an age up to 70. With regional assessment results of HCHO levels in over 700 residential homes of Hong Kong from 1995 to 2002, mathematical expressions of the HCHO exposure risk were proposed. The results showed that for a resident, age 70, the estimated risk of LLE at 95% confidence intervals was 0.3 day to 10.4 days due to the exposure of HCHO in the home. This study would be a useful reference in evaluating the environmental risk of HCHO in residential homes of Hong Kong.