Modelling short-term effects of ozone on morbidity: an application to the city of Milano, Italy, 1995–2003

In this paper, we explore a range of concerns that arise in measuring short-term effects of ozone on health. In particular, we tackle the problem of mea- suring exposure using alternative daily measures of ozone derived from hourly con- centrations. We adopt the exposure paradigm of Chiogna and Bellini (Environmetrics 13:55–69, 2002) extending it to ozone concentrations, and we compare its perfor- mances with respect to traditional exposure measures by exploiting model selection. To investigate the stability of model selection, we then apply the idea of bootstrapping the modelling process.