Combining land use regression models and fixed site monitoring to reconstruct spatiotemporal variability of NO2 concentrations over a wide geographical area.

The epidemiological research benefits from an accurate characterization of both spatial and temporal variability of exposure to air pollution. This work aims at proposing a method to combine the high spatial resolution of Land Use Regression (LUR) models with the high temporal resolution of fixed site monitoring data, to model spatiotemporal variability of NO2 over a wide geographical area in Northern Italy. We developed seasonal LUR models to reconstruct the spatial distribution of a scaling factor that relates local concentrations to those measured at two reference central sites, one for the northern flat area and one for the southern mountain area. We calculated the daily average concentrations at 19 locations spread over the study areas as the product of the local scaling factor and the reference central site concentrations. We evaluated model performance comparing modeled and measured NO2 data. LUR model's R2 ranges from 0.76 to 0.92. The main predictors refers substantially to traffic, industrial land use, buildings volume and altitude a.s.l. The model's performance in reproducing measured concentrations was satisfactory. The temporal variability of concentrations was well captured: Spearman correlation between model and measures was >0.7 for almost all sites. Model's average absolute errors were in the order of 10µgm-3. The model for the southern area tends to overestimate measured concentrations. Our modeling framework was able to reproduce spatiotemporal differences in NO2 concentrations. This kind of model is less data-intensive than usual regional atmospheric models and it may be very helpful to assess population exposure within studies in which individual relevant exposure occurs along periods of days or months.

Exposure to emissions from municipal solid waste incinerators and miscarriages: a multisite study of the MONITER Project.

BACKGROUND: Miscarriages are an important indicator of reproductive health but only few studies have analyzed their association with exposure to emissions from municipal solid waste incinerators. This study analyzed the occurrence of miscarriages in women aged 15-49years residing near seven incinerators of the Emilia-Romagna Region (Northern Italy) in the period 2002-2006. METHODS: We considered all pregnancies occurring in women residing during the first trimester of pregnancy within a 4km radius of each incinerator. Addresses were geocoded and exposures were characterized by a dispersion model (ADMS Urban model) producing pollution maps for incinerators based on PM10 stack measurements and for other pollution sources based on NOx ground measurements. Information on pregnancies and their outcomes was obtained from the Hospital Discharge Database. Simplified True Abortion Risks (STAR)×100 estimated pregnancies were calculated. We ran logistic regressions adjusting for maternal characteristics, exposure to other sources of pollution, and sites, considering the whole population and stratifying by miscarriage history. RESULTS: The study analyzed 11,875 pregnancies with 1375 miscarriages. After adjusting for confounders, an increase of PM10 due to incinerator emissions was associated with an increased risk of miscarriage (test for trend, p=0.042). The odds ratio for the highest quartile of exposed versus not exposed women was 1.29, 95% CI 0.97-1.72. The effect was present only for women without previous miscarriages (highest quartile of exposed versus not exposed women 1.44, 95% CI 1.06-1.96; test for trend, p=0.009). CONCLUSION: Exposure to incinerator emissions is associated with an increased risk of miscarriage. This result should be interpreted with those of a previous study on reproductive health conducted in the same area that observed an association between incinerator exposure and preterm births.

A comparison between self-reported and GIS-based proxies of residential exposure to environmental pollution in a case-control study on lung cancer.

In epidemiological studies both questionnaire results and GIS modeling have been used to assess exposure to environmental risk factors. Nevertheless, few studies have used both these techniques to evaluate the degree of agreement between different exposure assessment methodologies. As part of a case-control study on lung cancer, we present a comparison between self-reported and GIS-derived proxies of residential exposure to environmental pollution. 649 subjects were asked to fill out a questionnaire and give information about residential history and perceived exposure. Using GIS, for each residence we evaluated land use patterns, proximity to major roads and exposure to industrial pollution. We then compared the GIS exposure-index values among groups created on the basis of questionnaire responses. Our results showed a relatively high agreement between the two methods. Although none of these methods is the "exposure gold standard", understanding similarities, weaknesses and strengths of each method is essential to strengthen epidemiological evidence.

Combined sedation with oral chlordemethyldiazepam and midazolam by nasal route in third molar surgery.

AIM: This study was performed to evaluate the effects on the cardiocirculatory system, on perioperative anxiety and compliance of sedation with 2 benzodiazepines, chlordemethyldiazepam (CDDZ) a long acting oral drug for presedation and midazolam, a short acting drug, administered by nasal route to induce intraoperative sedation. METHODS: Fifty randomized patients undergoing third molar extraction at the Dental Clinic, University of Padua, were preoperatively evaluated. Anxiety was evaluated through a visual, analogue, scale (VAS) of 10 cm, a questionnaire of adjectives called interval scale of anxiety response (ISAR) and the Newman test was applied to evaluate the changes in psychomotor functions. All patients were treated with 1 ml of oral CDDZ for presedation and midazolam by the nasal route for intraoperative sedation at doses of 1 mg in Group 1 (25 patients) and 2 mg in Group 2 (25 patients). In all patients preoperative cardiocirculatory parameters were evaluated and in the first 20 min after the beginning of intervention. At the end of intervention the Newman test was reapplied, anxiety and postoperative cardiocirculatory data were reevaluated and the quality of the intervention judged in an interview made 1 week after the intervention (quality of the sedation technique, perioperative pain intensity, assumption of analgesic drugs, swelling, amnesia etc. after intervention). RESULTS: The treatment with 1 mg CDDZ + 2 mg midazolam by nasal route is the best association to slightly attenuate intra- and postoperative cardiocirculatory response, anxiety and to improve the quality of the treatment without interfering on the psychomotor response of patients at the time of the discharge. CONCLUSION: To conclude, the sedative technique employed is easily applied by the dentist, and is safe, efficacious and well tolerated by patients.