Artikel
Personal exposure to UFP in distinct microenvironments
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Veröffentlicht: | 2. September 2009 |
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Introduction: Assessing long-term personal exposure to size-specific particulate matter (PM) remains problematic in large epidemiological studies. One approach is to model personal exposure based on time-activity questionnaires and literature-based exposure values for specific microenvironments (MEs). We measured personal ultrafine particle exposure (< 100 nm, UFP) in selected MEs and compared measured exposures with literature-derived exposure estimates.
Materials and Methods: A mobile TSI CPC 3007 was used to derive time resolved personal UFP exposures for a 48 h period in 22 non-smoking volunteers. Participants filled in questionnaires on personal behaviour, properties of their home and use of transportation, and kept a diary during the measurement period. Relevant MEs known to influence personal UFP exposure (indoor cooking, indoor cleaning, in-traffic) were defined a priori.
Results: A total of 34, 20, and 59 episodes with a mean duration of 53, 74, and 45 min were recorded for "cooking", "cleaning", and "in-traffic", respectively. Periods with environmental tobacco smoke exposure were excluded due to small numbers. Mean episode exposure concentrations for “cooking” ranged from 1,000–201,000/cm³ with a median of 12,600/cm³ (Interquartile range (IQR) 5,650-27,900/cm³, geometric mean (GM) 11,900/cm³). Literature values (N=7) range from 3,000-111,000/cm³. Exposure values for “Cleaning” ranged from 2,000-109,000/cm³ (median 8,700/cm³, IQR 6,100-14,300/cm³, GM 10,600/cm³). Literature values (N=9) range from 550-41,000/cm³. The median in-traffic exposure was 6,350/cm³ (1,000-98,100/cm³, IQR 3,000-12100/cm³, GM 6000/cm³). Literature values (N=3) range from 2,000-16,000/cm³. Variation of exposure within individual episodes, within subjects and between subjects was substantial for all three MEs.
Discussion: The measured range of values compare well with literature values but also exhibit a large range. Cooking resulted in the highest mean exposure. The large within and between subject variation for specific MEs leads to high uncertainties in personal exposure estimation and necessitates further characterization of MEs when assessing personal exposure with a microenvironmental model.