Risk Reduction Behaviors Regarding PM Exposure among Outdoor Exercisers in the Nanjing Metropolitan Area, China.

: This study aimed to describe risk reduction behaviors regarding ambient particulate matter with a diameter of 2.5 μm or less (PM) among outdoor exercisers and to explore potential factors influencing those behaviors in the urban area of Nanjing, China. : A cross-sectional convenience sample survey was conducted among 302 outdoor exercisers in May 2015. Descriptive analysis was used to describe demographics, outdoor physical activity patterns, knowledge of PM and risk reduction behaviors. Multivariate logistic regression analysis was then used to explore factors that influence the adoption of risk reduction behaviors. : The most common behavior to reduce PM exposure was minimizing the times for opening windows on hazy days (75.5%), and the least common one was using air purifiers (19.3%). Two thirds of respondents indicated that they wore face masks when going outside in the haze (59.5%), but only 13.6% of them would wear professional antismog face masks. Participants adopting risk reduction behaviors regarding PM exposure tended to be females, 50⁻60 year-olds, those with higher levels of knowledge about PM and those who had children. : These findings indicate the importance of improving knowledge about PM among outdoor exercisers. Educational interventions should also be necessary to guide the public to take appropriate precautionary measures when undertaking outdoor exercise in high PM pollution areas.