Indoor exposures and acute respiratory effects in two general population samples from a rural and an urban area in Italy

A study of indoor air exposures and acute respiratory effects in adults was conducted in the Po Delta (rural) and Pisa (urban) areas of Italy. Indoor exposures were monitored for nitrogen dioxide (NO2) and particulate matter o2.5 mm (PM2.5) for 1 week during the winterorsum mer in a total of 421 houses (2/3 in Pisa). Information on house characteristics, subjects' daily activity pattern and presence of acute respiratory symptoms was collected by a standardized questionnaire. Peak expiratory flow (PEF) maneuvers were performed by adult subjects four times daily; maximum amplitude and diurnal variation were taken into account. Indices of NO2 and PM2.5 exposures were computed as the product of weekly mean pollutant concentration by the time of daily exposure. Mean levels of pollutants were significantly higher in winter than in summer, regardless of the area. The relationship between exposure indices and acute respiratory symptoms was investigated only in winter. In spite of a slightly lower indoor level in the urban than in the rural ar ea in winter(N O2: 15 vs. 22 ppb; PM2.5: 67 vs. 76 mg/m3), prevalence rates of acute respiratory symptoms were significantly higher in the urban than in the rural area. Acute respiratory illnesses with fever were significantly associated with indices of NO2 (odds ratio (OR)¼1.66; 95% CI¼1.082.57) and PM2.5 exposures (OR¼1.62; 95% CI¼1.042.51), while bronchitic/asthmatic symptoms were associated only with PM2.5 (OR¼1.39; 95% CI¼1.171.66). PEF variability was positively related only to PM2.5 exposure index (OR¼1.38; 95% CI¼1.241.54, form aximum amplitude; OR¼1.37; 95% CI¼1.231.53, for diurnal variation). In conclusion, indoor pollution exposures were associated with the presence of acute respiratory symptoms and mild lung function impairment in a rural and an urban area of Northern-Central Italy.