Time-activity Patterns among Residents in Representative Urban Areas of Lanzhou City

Objective To investigate the time-activity patterns of representative residents in Lanzhou City, and provide the evidence for accurate assessment of the impact of urban air pollution on residents' health.

Methods A total of 1 727 residents from 709 households in representative living and industrial urban areas of Lanzhou City were surveyed from October to November in 2016. The differences of time-activity patterns in various urban areas, gender, age, education levels and occupational characteristics were analyzed. Then the carcinogenic risk of formaldehyde in the house was estimated.

Results The indoor activity time of Lanzhou residents in weekdays and rest days was 1 239 and 1 275 min/d, respectively, the total outdoor activity time was 136 and 102 min/d, respectively, and transportation time was 65 and 63 min/d, respectively. Male and skilled workers spend longer time outdoor than female and others professionals. The elderly and retirees spend more time at home than young people, service staff and office staff have a long indoor working time, young people and skilled workers take a longer time for transportation. The cancer risk probability of formaldehyde was 3.51×10^-4 for adult man, 3.41×10^-4 for adult woman, both of which exceeded the acceptable level (1.00×10^-6).

Conclusions The time-activity patterns in population of different regions and characteristics should be combined with the health risk assessment and prevention and control of air pollutionh, as well as to improve the accuracy of evaluation and the reliability of prevention and control.