Social and physical environmental factors influencing adolescents' physical activity in urban public open spaces: a qualitative study using walk-along interviews

Most previous studies examining physical activity in Public Open Spaces (POS) focused solely on the physical environment. However, according to socio-ecological models the social environment is important as well. The aim of this study was to determine which social and physical environmental factors affect adolescents' visitation and physical activity in POS in low-income neighbourhoods. Since current knowledge on this topic is limited, especially in Europe, qualitative walk-along interviews were used to obtain detailed and context-specific information. Participants (n = 30, aged 12-16 years, 64% boys) were recruited in POS in low-income neighbourhoods in Brussels, Ghent and Antwerp (Belgium). Participants were interviewed while walking in the POS with the interviewer. Using this method, the interviewer could observe and ask questions while the participant was actually experiencing the environment. All audio-recorded interviews were transcribed and analysed using Nvivo 10 software and thematic analysis was used to derive categories and subcategories using a grounded theory approach. The most important subcategories that were supportive of visiting POS and performing physical activity in POS were; accessibility by foot/bicycle/public transport, located close to home/school, presence of (active) friends and family, cleanliness of the POS and features, availability of sport and play facilities, large open spaces and beautiful sceneries. The most important subcategories that were unsupportive of visiting POS and physical activity in POS were; presence of undesirable users (drug users, gangs and homeless people), the behaviour of other users and the cleanliness of the POS and features. Social factors appeared often more influential than physical factors, however, it was the combination of social and physical factors that affected adolescents' behaviour in POS. Easily accessible POS with high quality features in the proximity of adolescents' home or school may stimulate physical activity, if adolescents also experience a safe and familiar social environment.

Air pollution levels measured at traffic hot spots : Brisbane urban corridor study

Air pollution levels were monitored continuously over a period of 4 weeks at four sampling sites along a busy urban corridor in Brisbane. The selected sites were representative of industrial and residential types of urban environment affected by vehicular traffic emissions. The concentration levels of submicrometer particle number, PM2.5, PM10, CO, and NOx were measured 5-10 meters from the road. Meteorological parameters and traffic flow rates were also monitored. The data were analysed in terms of the relationship between monitored pollutants and existing ambient air quality standards. The results indicate that the concentration levels of all pollutants exceeded the ambient air background levels, in certain cases by up to an order of magnitude. While the 24-hr average concentration levels did not exceed the standard, estimates for the annual averages were close to, or even higher than the annual standard levels.

How can land and urban development make houses healthier?

Traditionally, the main focus of the professional community involved with indoor air quality has been indoor pollution sources, preventing or reducing their emissions, as well as lowering the impact of the sources by replacing the polluted indoor air with "fresh" outdoor air. However, urban outdoor air cannot often be considered "fresh", as it contains high concentrations of pollutants emitted from motor vehicles - the main outdoor pollution sources in cities. Evidence from epidemiological studies conducted worldwide demonstrates that outdoor air quality has considerable effects on human health, despite the fact that people spend the majority of their time indoors. This is because pollution from outdoors penetrates indoors and becomes a major constituent of indoor pollution. Urban land and transport development has significant impact on the overall air quality of the urban airshed as well as the pollution concentration in the vicinity of high-density traffic areas. Therefore, an overall improvement in indoor air quality would be achieved by lowering urban airshed pollution, as well as by lowering the impact of the hot spots on indoor air. This paper explores the elements of urban land and vehicle transport developments, their impact on global and local air quality, and how the science of outdoor pollution generation and transport in the air could be utilized in urban development towards lowering indoor air pollution.