Identifying low-PM2.5 exposure commuting routes for cyclists through modeling with the random forest algorithm based on low-cost sensor measurements in three Asian cities.

Cyclists can be easily exposed to traffic-related pollutants due to riding on or close to the road during commuting in cities. PM2.5 has been identified as one of the major pollutants emitted by vehicles and associated with cardiopulmonary and respiratory diseases. As routing has been suggested to reduce the exposures for cyclists, in this study, PM2.5 was monitored with low-cost sensors during commuting periods to develop models for identifying low exposure routes in three Asian cities: Taipei, Osaka, and Seoul. The models for mapping the PM2.5 in the cities were developed by employing the random forest algorithm in a two-stage modeling approach. The land use features to explain spatial variation of PM2.5 were obtained from the open-source land use database, OpenStreetMap. The total length of the monitoring routes ranged from 101.36 to 148.22 km and the average PM2.5 ranged from 13.51 to 15.40 µg/m³ among the cities. The two-stage models had the standard k-fold cross-validation (CV) R2 of 0.93, 0.74, and 0.84 in Taipei, Osaka, and Seoul, respectively. To address spatial autocorrelation, a spatial cross-validation approach applying a distance restriction of 100 m between the model training and testing data was employed. The over-optimistic estimates on the predictions were thus prevented, showing model CV-R2 of 0.91, 0.67, and 0.78 respectively in Taipei, Osaka, and Seoul. The comparisons between the shortest-distance and lowest-exposure routes showed that the largest percentage of reduced averaged PM2.5 exposure could reach 32.1% with the distance increases by 37.8%. Given the findings in this study, routing behavior should be encouraged. With the daily commuting trips expanded, the cumulative effect may become significant on the chronic exposures over time. Therefore, a route planning tool for reducing the exposures shall be developed and promoted to the public.

Satisfaction with neighbourhood environment moderates the associations between objective neighbourhood environment and leisure-time physical activity in older adults in Beijing, China.

Asia is ageing fast. To develop more effective health promotion initiatives among older adults, more knowledge of the environmental correlates of physical activity is needed. However, research in this age group is rare, and most existing studies have been conducted within Western contexts. The present study explores the interaction effects of objective neighbourhood environment and satisfaction with neighbourhood environment on leisure-time physical activity in older adults in Beijing, China. This study follows a cross-sectional design and involves older adults aged 65 years and over. The questionnaire was collected in 2018 and 2,061 older adults living in Yanshan, Beijing, China were included in the analysis. Linear regression was applied to examine the effects. The findings show that residents who live in places with higher levels of walkability, or those who are more satisfied with neighbourhood environment (either path/road/street condition or recreational resources) spent significantly longer participating in leisure-time physical activity. However, the objective neighbourhood accessibility of recreational resources was not a significant factor of physical activity. Satisfaction with neighbourhood recreational resources can significantly moderate the relationship between objective neighbourhood accessibility of recreational resources and leisure-time physical activity respectively. This is the first study conducted in China examining the relationships between objective neighbourhood environment, satisfaction with neighbourhood environment and leisure-time physical activity among older adults. This study may have implications for urban planning and service provision planning. The design of built environments that considers quality rather than only quantity can play a significant role in improving older adults' leisure-time physical activity.

Gender differences in cigarette smoking and alcohol drinking among adolescents and young adults in Hanoi, Shanghai, and Taipei.

OBJECTIVE: This study aimed to examine gender differences in smoking and alcohol drinking behaviors in three Asian cities of Hanoi, Shanghai, and Taipei, and to assess the magnitude of gender differences across the three cities. METHODS: A total of 17,016 adolescents (age: 15-19 years) and young adults (age: 20-24 years) were selected using multi-stage sampling methods and surveyed in face-to-face interviews. A total of 16,554 unmarried respondents were included in this analysis. RESULTS: Gender differences were significant for smoking only, drinking only, and both behaviors in each city. Male respondents were 30.66 times more likely to report smoking only than female respondents in Hanoi, followed by Shanghai and Taipei. This pattern was similar for drinking only and both smoking and drinking behaviors. CONCLUSIONS: The magnitude of gender differences in smoking only, drinking only, and both behaviors widely varies across the three cities. Further research can examine how these differences may be used to prevent and reduce smoking and drinking in the adolescent and young adult population.

Drunkenness and its association with health risk behaviors among adolescents and young adults in three Asian cities: Hanoi, Shanghai, Taipei.

PURPOSE: To assess the prevalence of drunkenness among adolescents in Hanoi, Shanghai, and Taipei and explore the association between heavy drinking and other health risk behaviors. METHODS: The data are drawn from the Three-city Collaborative Study of Adolescent Health, conducted in Hanoi, Shanghai, and Taipei in 2006. A sample of 17,016 adolescents and young adults, aged 15-24 years, was selected by multistage sampling. Descriptive analysis was used to estimate the proportion of drunkenness and other health risk behaviors. Multivariate logistic regression was used to investigate relationships between drunkenness and risky health behaviors. RESULTS: The proportions of the sample getting drunk during the past month were 6.36%, 4.53%, and 8.47% in Hanoi, Shanghai, and Taipei, respectively. More males than females reported drunkenness in all three cities, with the difference highest in Hanoi (11.08% vs. 1.14%) and lowest in Taipei (9.69% vs. 7.18%). Different levels of relationship between drunkenness and health risk behaviors, such as anxiety, suicidal ideation, smoking, gambling, fighting, drinking and driving, and having sexual intercourse, were found across the three cities; an exception was nonuse of contraception. CONCLUSION: Drunkenness was positively associated with many health risk behaviors. It may serve as an indicator of other risky behaviors. Interventions to reduce drinking and drunkenness may contribute considerably to the prevention of other risk behaviors and to adolescent safety and well-being.