Urban areas are growing fast worldwide and there is an increasing concern about the relations between urbanization, environmental threats, the quality of living spaces and human health. A healthy living environment is a prerequisite for good health. Research in environmental epidemiology clearly illustrates a direct health impact of indoor (Mendell et al. 2011, Casas et al. 2016, Lin et al. 2013, Cox et al. 2013) and outdoor pollution (Casas et al. 2016, Foraster et al. 2014). Living in healthy and green areas is associated with better self-assessed health (De Jong et al. 2012, Bowler et al. 2010), better mental health (Triguero-Mas 2015), lower risks of cardio-vascular and respiratory diseases and lower mortality from related causes (Gascon et al. 2016). This may be due to their lower air pollution and lower noise levels, higher opportunities for physical activity, facilitation of social contacts, and/or promotion of recovery from fatigue and stress.
To date, there are few studies dealing with the association between the in- and outdoor living environment and health in Belgium, let alone in the Brussels Capital Region. The ongoing GRESP-HEALTH project intends to put an end to this situation through a study of the impact of green spaces on health in Belgium (https://www.belspo.be/belspo/brain-be/projects/GRESP-HEALTH_en.pdf). The current project proposal will use this GRESP-HEALT project as a stepping stone and disentangle the interrelations between (indoor and outdoor) environmental factors, social background factors and health in the Brussels Capital Region. It will investigate the impact of social stratifiers – socioeconomic position, migrant background, age and gender – on the association between environmental quality and health and mortality. Environmental quality refers to the characteristics of the in- and outdoor living environment and will be measured in this project through characteristics of the dwelling (indoor environment), and characteristics of green spaces, outdoor air and noise pollution (outdoor environment). Green&Quiet will use a mixed method and intersectionality approach, which are both rarely implemented in the field of environmental epidemiology.
Intersectionality theory seeks to enhance understandings of social stratifiers by arguing that multiple marginalizations, such as those experienced by migrant women in lower social classes for instance, are mutually constituted and cannot be understood by approaches that treat social class, migrant and sex/gender distinctively. According to Bauer (2014): “Intersectionality will enrich population health research through improved validity and greater attention to both heterogeneity of effects and causal processes producing health inequalities” (p. 10). Green&Quiet will thus assume that what it means to live in a polluted environment and what the health implications are, may be different for men versus women, for lower versus higher educated, for young versus old people, for Moroccans and Turkish versus native-born communities. This makes sense in that living environment can be constituted through cultural meanings and processes (Bauer, 2014).
The distinctive and innovative characteristics of the Green&Quiet project can be summarized as follows: i) focus on intersectionality; ii) use of a mixed method approach (quantitative and qualitative research design); iii) integration of indicators of indoor pollution; iv) application of objective as well as subjective indicators of the in- and outdoor living environment; v) exploitation of new census data (census 2011); and vi) profound focus on the Brussels Capital Region. The Green&Quiet project intends to move from “description” to “explanation” by digging deeper into pathways and mechanisms behind the threefold association between environmental factors, social stratifiers and health/mortality.
The main research question crystalizes into four sub-questions. The first research question probes into the relation between indicators of the in- and outdoor living environment and health in the Brussels Capital Region stratifying the population according to socioeconomic position, migrant background, gender and age. These social stratifiers may determine variation in the experience with, the exposure to and the impact of the living environment on health/mortality and may thus mediate and modify the impact of the living environment on health and mortality, certainly when less-advantageous social positions are coinciding in individuals, as we know from intersectionality theory (Virtuell-Fuentes et al. 2012).
Excellent data on these dimensions are available at Interface Demography in the National Mortality Database. This database consists of a linkage between the 1991 and 2001 census and register data on mortality and migration between 1991 and 2015. Data of the census 2011 will be added in the context of the Green&Quiet project. As the database provides population-wide information, it creates an ideal setting for an intersectionality approach. The social background information of the census will be linked to indicators of the in- and outdoor living environment available in ecologic databases at the level of the statistical ward. Information relates to green spaces (percentage of green space, proximity to the closest green space, accessibility to green areas and a total exposure index to green spaces), air pollution (levels of PM10, PM2.5 and NO2, traffic density and distance to major roads from the residential area) and noise pollution (sound pressure levels in dB of road, rail and traffic noise for different time windows; day, evening and night). The project will not only take objective indicators of the outdoor environment into account, but also subjective indicators relating to the perception of environmental characteristics (available in the census 2001). In addition, the census 2001 allows for the construction of proxies for potential indoor polluters (main source of energy to heat the dwelling, overcrowding, isolation of the dwelling, year of construction of the dwelling, renovations since 1991, availability of a garden, condition of the electric installation, of the inner and outer walls, the windows and the roof). In order to take a holistic approach of health, Green&Quiet will focus on self-assessed health (available in the census 2001), all-cause mortality and on selected causes of death. State of the art statistical models such as multilevel logistic and Poisson regressions will be used to inquire the interrelations between living environment, social background factors (socioeconomic position, migration background, age and gender) and health/mortality.
In order to identify the underlying mechanisms behind the observed patterns, Green&Quiet will perform a qualitative analysis. An important pathway to understand the interrelations between social factors, living environment and health undoubtedly relates to the differential way in which in- and outdoor environment is used, experienced and perceived by social groups. As an intermediate step towards the qualitative analysis, the second research question will probe into the association between the abovementioned objective indicators of the in- and outdoor living environment and subjective (perception) indicators of the environment available in the census 2001 (perception of green in the neighborhood, air quality, noisiness, etc.) in an intersectionality approach. This quantitative analysis will show how perceptions differ from ‘objective reality’ (measured through objective indicators) in the distinctive social groups.
The third research question will investigate whether different social groups have different usage, perceptions and convictions about their living environment. This part of the project will use a qualitative research strategy, which is very innovative in the field of environmental epidemiology. The qualitative design will consist of i) a realist literature review regarding international qualitative studies on the usage and perception of the living environment and health; ii) in-depth interviews with key stakeholders about the specificities of the Brussels context in terms of living environment and public (green) spaces; iii) in depth-interviews with Brussels’ citizens on their perception, (non-)usage and preferences regarding their immediate living environment and near green spaces/recreational zones; and iv) a concept mapping exercise around specific neighborhoods or recreational spaces, focusing on usage and future perspectives. These analyses will focus on gender, different age groups, socioeconomic positions and migrant communities to take into account the intersectionality perspective.
The fourth research question will address the implications of our research results for existing insights and knowledge about environmental health effects and the role of intersectionality in these effects. Given the variety of individual and contextual social and environmental characteristics that will be integrated and the holistic focus on health (self-assessed health, all-cause and cause-specific mortality), what does Green&Quiet offer as new insights and knowledge? The research results will be compared with other studies, positioning our output within a broader national and international context. We believe that Brussels represents a unique environment to carry out our project. In that regard, we refer to Brussels’ diversity with respect to its neighbourhoods, population composition, socioeconomic conditions and environmental living conditions with variations that are far greater than in many other parts of the country and even Europe.
Keywords: in- and outdoor environment, health and mortality, intersectionality, mixed method approach, environmental epidemiology
Duration: 2018 -2022