Search

On October 2004, a sampling survey was carried out in Florence to estimate urban fine particle exposure concentrations inside commuting vehicles during workdays characterized by heavy traffic. Portable samplers were positioned inside four regularly scheduled diesel-powered buses and four taxis during eight weekdays. Each sampler consisted of a 2.5μm size pre-separator cyclone, a direct-reading data logging photometer (pDR-1200), and a 4Lmin−1 filter sampler for the determination of PM2.5 mass concentration. Based on reflectance analysis measurements, a PM2.5 Black Smoke Index was determined for each filter, and the elemental composition of the PM2.5 was analyzed by Particle Induced X-ray Emission (PIXE). PM2.5 mass concentrations inside the vehicles correlated well with the urban ambient air PM2.5 concentrations measured at the fixed-site monitoring stations. The PM2.5 excess above the urban ambient level was on average 32μgm− 3 (range: 22–52μgm− 3) and 20μgm− 3 (range: 11–29μgm− 3) in buses and taxis, respectively. The PM2.5-bound sulfur concentration was also higher in the buses than in the taxis. Based on daily Time-Microenvironment-Activity-Diary (TMAD) data, the Florentines spend on average 9.7% of their day in traffic, and the corresponding average exposure is approximately 12% of their daily PM2.5 personal exposure. The obtained data could be used to plan interventions to minimize the PM2.5 citizen exposures in commuting. [Copyright &y& Elsevier]

Abstract: Objective: Personal exposure to airborne benzene is influenced by various outdoor and indoor sources. The first aim of this study was to assess the benzene exposure of a sample of urban inhabitants living in an inner-city neighborhood of Florence, Italy, excluding exposure from active smoking. The secondary objective was to differentiate the personal exposures according to personal usage patterns of the vehicles. Methods: A sample of 67 healthy non-smokers was monitored by passive samplers during two 4-weekday campaigns in winter and late spring. Simultaneously, benzene measurements were also taken for a subset of participants, inside and outside their houses. A 4-day time microenvironment activity diary was completed by each subject during each sampling period. Other relevant exposure data were collected by a questionnaire before the sampling. Additional data on urban ambient air benzene levels were also available from the public air quality network. The passive samplers, after automated thermal desorption, were analyzed by GC-FID. Results: Benzene personal exposure levels averaged 6.9 (SD=2.1) and 2.3 (SD=0.7) μg/m3 in winter and spring, respectively. Outdoor and indoor levels showed high correlation in winter and poor in spring. In winter the highest benzene personal exposure levels were for people traveling by more public transport, followed by users of only car and by users of only bus respectively. Conclusions: The time spent in-transport for work or leisure makes a major contribution to benzene exposure among Florentine non-smoking citizens. Indoor pollution and transportation means contribute significantly to individual exposure levels especially in winter season. [Copyright &y& Elsevier]