Studies on risk perception and ‘proximity’ usually compare populations living close to or far away from alleged pollution sources. Taking a different perspective, this paper compares the risk perception profiles of populations residing in the neighborhood of two petrochemical sites in Sicily (Italy), in order to check for similarities and differences. Based on the results of a survey carried out in the period 2008–2009 (1222 interviews), risk perception is investigated; finding that on a list of 15 social risks, the two populations show a similar risk perception only as far as hazards that can be retraced to the territorial industrial environment are concerned, while other risks are differently perceived. Specific risk perception indicators are presented and the relationship between risk perception, socioeconomic characteristics, and health is also deepened. The conclusion of this study is that proximity to industrial pollution sources influences risk perception and assimilates risk perception profiles of populations.

Background: The analysis of risk for the population residing and/or working in contaminated areas raises the topic of commuting. In fact, especially in contaminated areas, commuting groups are likely to be subject to lower exposure than residents. Only very recently environmental epidemiology has started considering the role of commuting as a differential source of exposure in contaminated areas. In order to improve the categorization of groups, this paper applies a gravitational model to the analysis of residential risk for workers in the Gela petrochemical complex, which began life in the early 60s in the municipality of Gela (Sicily, Italy) and is the main source of industrial pollution in the local area.Results: A logistic regression model is implemented to measure the capacity of Gela "central location" to attract commuting flows from other sites. Drawing from gravity models, the proposed methodology: a) defines the probability of finding commuters from municipalities outside Gela as a function of the origin's "economic mass" and of its distance from each destination; b) establishes "commuting thresholds" relative to the origin's mass. The analysis includes 367 out of the 390 Sicilian municipalities. Results are applied to define "commuters" and "residents" within the cohort of petrochemical workers. The study population is composed of 5,627 workers. Different categories of residence in Gela are compared calculating Mortality Rate Ratios for lung cancer through a Poisson regression model, controlling for age and calendar period. The mobility model correctly classifies almost 90% of observations. Its application to the mortality analysis confirms a major risk for lung cancer associated with residence in Gela.Conclusions: Commuting is a critical aspect of the health-environment relationship in contaminated areas. The proposed methodology can be replicated to different contexts when residential information is lacking or unreliable; however, a careful consideration of the territorial characteristics ("insularity" and its impact on transportation time and costs, in our case) is suggested when specifying the area of application for the mobility analysis.