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In Swedish cities, many residents live in neighborhoods where the air is more polluted, noise levels are higher and green spaces scarcer, conditions that often correlate with socioeconomic status, housing tenure and country of birth. This is shown by a new study from the University of Gothenburg.

The researchers analyzed data from more than 23,000 people in six Swedish cities. For each participant, they mapped three environmental factors known to affect health: concentrations of fine particulate matter in the air (PM_2.5), traffic noise, and access to nearby green areas.

These metrics were then linked to socioeconomic characteristics of both the individuals and their neighborhoods; for example, the share of foreign-born residents, the proportion with low incomes, and the proportion of rental housing. The results, in Sustainable Cities and Society, show that several of these groups live in areas with an unhealthy urban environment.

The share of rental living proved to be an especially strong marker: in every city this variable was closely associated with higher environmental exposure. In some cities, neighborhood social composition explained up to 80% of the variation in air pollution levels.

Complex relationships

The analysis also revealed an unexpected pattern. In some cities, neighborhoods with a low proportion of residents with upper-secondary education, or with high unemployment, were exposed to less noise, cleaner air or more greenery. These relationships were not consistent everywhere—the patterns varied both between cities and between different indicators of socioeconomic disadvantage.

"It's easy to assume that every kind of social vulnerability automatically brings a poorer environmental setting, but that is not always the case. Our results differ depending on the city and on which socioeconomic factor you examine," says Mehjar Azzouz, physician and doctoral student at the Sahlgrenska Academy, University of Gothenburg.

"To design the right measures and create a fair urban environment, cities need to understand their local conditions and identify who is at risk and vulnerable."

Preventing ill-health

The study did not examine health outcomes, but it mapped risk environments that research has linked to stress, cardiovascular disease and poorer mental health. By understanding how these factors are distributed socially and geographically, municipalities can plan more equitable urban environments.

The analysis shows that where you live, rather than your own income or education, is the main determinant of your exposure to unhealthy environmental factors.