The quality of the physical environment has effects on well-being, social participation and health. Populations with high spatial concentrations or densities (for example, the density of dwellings requiring major repairs) inversely influence quality of life, in terms of social behaviour and health, since they 1) inversely impact on the landscape, interfering with the ability to enjoy and appreciate the environment; and 2) result in concentrations of poor housing conditions, thus inversely impacting upon the environment and health. High levels of air pollution may severely impact health.