Ambient fine particulate matter air pollution & physical activity: A longitudinal study of university retirees in Beijing, China

Objectives: We examined the longitudinal relationship between ambient fine particulate matter (PM2.5) air pollution and physical activity-related health behaviors among university retirees in Beijing, China. Methods: Annual health surveys of retirees were conducted at Tsinghua University during 2011-2016. We conducted linear individual fixedeffect regression analyses to estimate the impact of ambient PM2.5 concentration on physical activity-related health behaviors among survey participants, adjusting for various time-variant individual characteristics and environmental measures. Results: An increase in ambient PM2.5 concentration by one standard deviation (56.6 μg/m3) was associated with a reduction in weekly total hours of walking by 4.69 (95% confidence interval=1.30-8.08), a reduction in leisure-Time Physical Activity Scale for the Elderly (PASE) score by 71.16 (28.91-113.41), and a reduction in total PASE score by 110.67 (59.25-162.08). An increase in ambient PM2.5 concentration by one standard deviation was associated with an increase in daily average hours of nighttime/daytime sleeping by 1.75 (1.24-2.26). The impact of ambient PM2.5 concentration on weekly hours of walking tended to be greater among men than among women. Conclusions: Air pollution significantly discouraged Chinese older adults from engaging in daily physical activities. Policy interventions are needed to reduce air pollution in China's urban areas.