title: Photometrically measured continuous personal PM(2.5) exposure: levels and correlation to a gravimetric method.
abstract: There is evidence that hourly variations in exposure to airborne particulate matter (PM) may be associated with adverse health effects. Still there are only few published data on short-term levels of personal exposure to PM in community settings. The objectives of the study were to assess hourly and shorter-term variations in personal PM(2.5) exposure in Helsinki, Finland, and to compare results from portable photometers to simultaneously measured gravimetric concentrations. The effect of relative humidity on the photometric results was also evaluated. Personal PM(2.5) exposures of elderly persons were assessed for 24 h every second week, resulting in 308 successful measurements from 47 different subjects. Large changes in concentrations in minutes after cooking or changing microenvironment were seen. The median of daily 1-h maxima was over twice the median of 24-h averages. There was a strong significant association between the two means, which was not linear. Median (95th percentile) of the photometric 24-h concentrations was 12.1 (37.7) and of the 24-h gravimetric concentrations 9.2 (21.3) microg/m3. The correlation between the photometric and the gravimetric method was quite good (R2=0.86). Participants spent 94.1% of their time indoors or in a vehicle, where relative humidity is usually low and thus not likely to cause significant effects on photometric results. Even outdoors, the relative humidity had only modest effect on concentrations. Photometers are a promising method to explore the health effects of short-term variation in personal PM(2.5) exposure.
authors.affiliation: Unit of Environmental Epidemiology, National Public Health Institute, Kuopio, Finland. timo.lanki@ktl.fi
authors.forename: Timo
authors.initials: T
authors.lastname: Lanki
authors.forename: Sari
authors.initials: S
authors.lastname: Alm
authors.forename: Juhani
authors.initials: J
authors.lastname: Ruuskanen
authors.forename: Nicole A H
authors.initials: NA
authors.lastname: Janssen
authors.forename: Matti
authors.initials: M
authors.lastname: Jantunen
authors.forename: Juha
authors.initials: J
authors.lastname: Pekkanen
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods* / Q000592:standards; D005387:Finland; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis*; D008019:Life Style; D010316:Particle Size; D010783:Photometry; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D000393:Air Pollutants