Contribution of metals in resuspended dust to indoor and personal inhalation exposures: Relationships between PM10 and settled dust
- DOI
- Language of the publication
- English
- Date
- 2018-07-26
- Type
- Article
- Author(s)
- Rasmussen, Pat E.
- Levesque, Christine
- Chénier, Marc
- Gardner, David H.
- Publisher
- Elsevier
Abstract
This study investigated relationships between element concentrations in settled indoor dust and airborne particulate matter (PM), and characterized element concentrations in fine (PM2.5) and coarse (PM10-2.5) modes of indoor, outdoor and personal microenvironments. Concentrations in settled house dust correlated significantly (99% CI) with concentrations in indoor PM10 for 11 out of 17 studied elements: Ag, Al, As, B, Cu, Fe, Mn, Pb, U, V and Zn. Five elements showed significant correlations between personal PM10 and settled dust, at 99% CI for Ag, Al, and As; and at 95% CI for Mn and Sb. These significant dust- PM10 correlations were observed in non-smokers’ homes in Windsor, Canada, in which PM10-2.5 comprised 55% of personal and indoor PM10 (median values in 2005 and 2006 respectively). Several elements were more concentrated in indoor PM10 compared to the settled dust from which the PM10 was derived, with enrichment factors ranging from 1.3 to 11. Dust fractionation experiments confirmed that most trace elements were enriched in resuspended PM10 compared to the parent dust sample. The <10 μm fraction averaged 50% ± 3.6% (by weight) of the total <80 μm dust samples (range 37–56%; n = 69). Concentrations of many elements in the <10 μm fraction of settled dust were 1.4–2.0 times higher in samples from heavily carpeted homes compared to non-carpeted homes, including Al, As and the transition metals Cd, Cr, Cu, Fe Ni and Zn. The results demonstrate that settled dust concentration data are useful for estimating indoor and personal exposures via the inhalation pathway.
Plain language summary
Health Canada is responsible for conducting research in support of risk assessment and risk management of metals under the Chemicals Management Plan. Settled house dust contains hundreds of inorganic and organic metallic compounds released from consumer products, furniture, building materials, coatings, combustion products, tracked-in soil and infiltrated ambient particles. Its ability to accumulate compounds makes house dust an excellent indicator of residential contamination. There is abundant evidence in the literature that re-suspended house dust contributes to indoor airborne particulate matter (PM) and the “personal cloud” (PM in the personal breathing zone). Despite this evidence, usage of dust contaminant concentration data has been generally limited to estimating exposures via the ingestion pathway, and not the inhalation pathway. Results from the present study provide several lines of evidence that support the utility of indoor settled dust concentration data for estimating indoor and personal inhalation exposures. Statistically significant correlations were observed between concentrations in settled house dust and indoor PM10 for Ag, Al, As, B, Cu, Fe, Mn, Pb, U, V and Zn. Five elements ( Ag, Al, As, Mn and Sb) showed significant correlations between personal PM10 and settled dust. Several metals of toxicological concern were shown to be elevated in the inhalable fraction (<10 µm) of settled dust from heavily carpeted homes compared to homes with little or no carpeting. The observation that many contaminants tend to concentrate in the finer fractions available for resuspension makes house dust a promising tool to assist Health Canada in refining estimates of personal and indoor exposures, and for identifying and mitigating indoor and outdoor sources of exposure.
Subject
- Health,
- Health and safety