Impact of ambient fine particulate matter air pollution on health behaviors: a longitudinal study of university students in Beijing, China

Abstract

Objectives: Poor air quality has become a national public health concern in China. This study examines the impact of ambient fine particulate matter (PM_2.5) air pollution on health behaviors among college students in Beijing, China.

Study design: Prospective cohort study.

Methods: Health surveys were repeatedly administered among 12,000 newly admitted students at Tsinghua University during 2012-2015 over their freshman year. Linear individual fixed-effect regressions were performed to estimate the impacts of ambient PM_2.5 concentration on health behaviors among survey participants, adjusting for various time-variant individual characteristics and environmental measures.

Results: Ambient PM_2.5 concentration was found to be negatively associated with time spent on walking, vigorous physical activity and sedentary behavior in the last week, but positively associated with time spent on nighttime/daytime sleep among survey participants. An increase in the ambient PM_2.5 concentration by one standard deviation (36.5 μg/m³) was associated with a reduction in weekly total minutes of walking by 7.3 (95% confidence interval [CI] = 5.3-9.4), a reduction in weekly total minutes of vigorous physical activity by 10.1 (95% CI = 8.5-11.7), a reduction in daily average hours of sedentary behavior by 0.06 (95% CI = 0.02-0.10) but an increase in daily average hours of nighttime/daytime sleep by 1.07 (95% CI = 1.04-1.11).

Conclusions: Ambient PM_2.5 air pollution was inversely associated with physical activity level but positively associated with sleep duration among college students. Future studies are warranted to replicate study findings in other Chinese cities and universities, and policy interventions are urgently called to reduce air pollution level in China's urban areas.

Keywords: Air pollution; China; College; Fine particulate matter; Health behavior; Physical activity.