title: Data analysis techniques: a tool for cumulative exposure assessment.
abstract: Everyone is subject to environmental exposures from various sources, with negative health impacts (air, water and soil contamination, noise, etc.or with positive effects (e.g. green space). Studies considering such complex environmental settings in a global manner are rare. We propose to use statistical factor and cluster analyses to create a composite exposure index with a data-driven approach, in view to assess the environmental burden experienced by populations. We illustrate this approach in a large French metropolitan area. The study was carried out in the Great Lyon area (France, 1.2 M inhabitants) at the census Block Group (BG) scale. We used as environmental indicators ambient air NO2 annual concentrations, noise levels and proximity to green spaces, to industrial plants, to polluted sites and to road traffic. They were synthesized using Multiple Factor Analysis (MFA), a data-driven technique without a priori modeling, followed by a Hierarchical Clustering to create BG classes. The first components of the MFA explained, respectively, 30, 14, 11 and 9% of the total variance. Clustering in five classes group: (1) a particular type of large BGs without population; (2) BGs of green residential areas, with less negative exposures than average; (3) BGs of residential areas near midtown; (4) BGs close to industries; and (5) midtown urban BGs, with higher negative exposures than average and less green spaces. Other numbers of classes were tested in order to assess a variety of clustering. We present an approach using statistical factor and cluster analyses techniques, which seem overlooked to assess cumulative exposure in complex environmental settings. Although it cannot be applied directly for risk or health effect assessment, the resulting index can help to identify hot spots of cumulative exposure, to prioritize urban policies or to compare the environmental burden across study areas in an epidemiological framework.
authors.affiliation: 1] EHESP Rennes, Sorbonne Paris Cité, Rennes, France [2] Inserm, UMR1085-IRSET (Institut de Recherche sur la Santé L'environnement et le Travail), Rennes, France [3] Lorraine University, Institut Elie Cartan de Lorraine, CNRS UMR 7502, Nancy, France [4] Lorraine University, INRIA, CNRS UMR7502, BIGS (INRIA Nancy - Grand Est/IECL), Nancy, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Lalloué
authors.affiliation: 1] Lorraine University, Institut Elie Cartan de Lorraine, CNRS UMR 7502, Nancy, France [2] Lorraine University, INRIA, CNRS UMR7502, BIGS (INRIA Nancy - Grand Est/IECL), Nancy, France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Monnez
authors.affiliation: 1] EHESP Rennes, Sorbonne Paris Cité, Rennes, France [2] Inserm, UMR1085-IRSET (Institut de Recherche sur la Santé L'environnement et le Travail), Rennes, France.
authors.forename: Cindy
authors.initials: C
authors.lastname: Padilla
authors.affiliation: 1] EHESP Rennes, Sorbonne Paris Cité, Rennes, France [2] Inserm, UMR1085-IRSET (Institut de Recherche sur la Santé L'environnement et le Travail), Rennes, France.
authors.forename: Wahida
authors.initials: W
authors.lastname: Kihal
authors.affiliation: 1] EHESP Rennes, Sorbonne Paris Cité, Rennes, France [2] Inserm, UMR1085-IRSET (Institut de Recherche sur la Santé L'environnement et le Travail), Rennes, France [3] Lorraine University Medical School, Nancy, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Zmirou-Navier
authors.affiliation: 1] EHESP Rennes, Sorbonne Paris Cité, Rennes, France [2] Inserm, UMR1085-IRSET (Institut de Recherche sur la Santé L'environnement et le Travail), Rennes, France.
authors.forename: Séverine
authors.initials: S
authors.lastname: Deguen
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D016000:Cluster Analysis; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D005163:Factor Analysis, Statistical; D005602:France / Q000453:epidemiology; D006801:Humans; D007221:Industry; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D009585:Nitrogen Dioxide / Q000032:analysis*; D009622:Noise; D012959:Socioeconomic Factors; D062206:Spatial Analysis; D013223:Statistics as Topic
chemical_list: D000393:Air Pollutants; D009585:Nitrogen Dioxide