[Health impact: considering only a plant assessment is not enough, an area assessment is also needed]

Environmental Impact Assessments (EIAs) often conclude with a "low" or at least "negligible" final health impact assessment (HIA) of the industrial plant under assessment. We explore the reasons for this - often simplistic - conclusion and offer suggestions on how to extend the assessment focus from just the plant to an appropriate impact area. For many assessments, the conclusions are easily predictable: the application of available risk functions to modest increases in pollution, in the presence of numerically small populations in the areas of greatest fallout and considering rather rare health outcomes, can only result in quantitatively modest health impacts. This is the classic situation of low sensitivity of the observation system due to the impossibility of containing the type II error (false negatives) since we cannot increase the exposed population at will. The risk is to give the green light to an industrial plant in which the apparently null or very limited damage is simply not properly detectable. There is hardly any trace of these elements in the HIA scoping phase. In environmental complex territories, the renewal or authorization of a new plant should consider not only the impact of the individual plant, but also the health profile of the population concerned and the context in which the industrial project is located. An 'HIA area' is therefore configured, aimed at the complex of environmental pressure factors that insist on the same area of impact of the plant. Epidemiology focuses on the exposed population, considers the 'current' state of health, hazard, and risk information from toxicology, and estimates individual exposure and the effects of exposure. The 'HIA area' can assess the impact of the complex of persistent emission sources, considering in the analysis the health status of the exposed population and the presence of specific vulnerabilities. The proposal is in line with what is already foreseen in the Essential levels of care and Environmental technical performance of the National Health Service.A basic condition is the establishment of functions dedicated to integrated environmental and health surveillance to update the health profile and carry out the 'HIA area' as an accompanying tool for local strategic planning. On these issues, the Italian Environment and Health Network (RIAS) has opened a discussion within the network and with any Italian regions.