title: Ambient ultrafine particle levels at residential and reference sites in urban and rural Switzerland.
abstract: Although there is evidence that ultrafine particles (UFP) do affect human health there are currently no legal ambient standards. The main reasons are the absence of spatially resolved exposure data to investigate long-term health effects and the challenge of defining representative reference sites for monitoring given the high dependence of UFP on proximity to sources. The objectives of this study were to evaluate the spatial distribution of UFP in four areas of the Swiss Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) and to investigate the representativeness of routine air monitoring stations for residential sites in these areas. Repeated UFP measurements during three seasons have been conducted at a total of 80 residential sites and four area specific reference sites over a median duration of 7 days. Arithmetic mean residential PNC scattered around the median of 10,800 particles/cm(3) (interquartile range [IQR] = 7800 particles/cm(3)). Spatial within area contrasts (90th/10th percentile ratios) were around two; increased contrasts were observed during weekday rush-hours. Temporal UFP patterns were comparable at reference and residential sites in all areas. Our data show that central monitoring sites can represent residential conditions when locations are well chosen with respect to the local sources--namely traffic. For epidemiological research, locally resolved spatial models are needed to estimate individuals' long-term exposures to UFP of outdoor origin at home, during commute and at work.
authors: Swiss Tropical and Public Health Institute , Basel 4002 , Switzerland.
authors: Reto
authors: R
authors: Meier
authors: Marloes
authors: M
authors: Eeftens
authors: Inmaculada
authors: I
authors: Aguilera
authors: Harish C
authors: HC
authors: Phuleria
authors: Alex
authors: A
authors: Ineichen
authors: Mark
authors: M
authors: Davey
authors: Martina S
authors: MS
authors: Ragettli
authors: Martin
authors: M
authors: Fierz
authors: Christian
authors: C
authors: Schindler
authors: Nicole
authors: N
authors: Probst-Hensch
authors: Ming-Yi
authors: MY
authors: Tsai
authors: Nino
authors: N
authors: Künzli
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D006798:Housing; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D052638:Particulate Matter / Q000032:analysis*; D012423:Rural Health; D012621:Seasons; D013557:Switzerland; D014504:Urban Health
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter