Risk remaining from fine particle contaminants after vacuum cleaning of hard floor surfaces

Abstract

In the indoor environment, settled surface dust often functions as a reservoir of hazardous particulate contaminants. In many circumstances, a major contributing source to the dust pool is exterior soil. Young children are particularly susceptible to exposure to both outdoor derived soil and indoor derived dust present in the indoor dust pool. This is because early in life the exploratory activities of the infant are dominated by touching and mouthing behavior. Inadvertent exposure to dust through mouth contact and hand-to-mouth activity is an inevitable consequence of infant development. Clean-up of indoor dust is, in many circumstances, critically important in efforts to minimize pediatric exposure. In this study, we examine the efficiency of vacuum cleaner removal of footwear-deposited soil on vinyl floor tiles. The study utilized a 5 x 10 foot (c. 152.5 x 305 cm) test surface composed of 1-foot-square (c. 30.5 x 30.5 cm) vinyl floor tiles. A composite test soil with moderately elevated levels of certain elements (e.g., Pb) was repeatedly introduced onto the floor surface by footwear track-on. The deposited soil was subsequently periodically removed from randomly selected tiles using a domestic vacuum cleaner. The mass and loading of soil elements on the tiles following vacuuming were determined both by wet wipe collection and by subsequent chemical analysis. It was found that vacuum cleaner removal eliminated much of the soil mass from the floor tiles. However, a small percentage of the mass was not removed and a portion of this residual mass could be picked up by moistened hand-lifts. Furthermore, although the post-vacuuming tile soil mass was sizably reduced, for some elements (notably Pb) the concentration in the residual soil was increased. We interpret this increased metal concentration to be a particle size effect with smaller particles (with a proportionately higher metal content) remaining in situ after vacuuming.

Characterising and communicating the potential hazard posed by potentially toxic elements in indoor dusts from schools across Lagos, Nigeria

“…Iron and Mn are major components of soil minerals and have been noted to be abundant elements in the earth crust. 59 Our Fe and Mn concentrations were within typical soil concentration ranges, with all measurements for both of these PTE falling below the earth's crust and continental shale values respectively. Our dust samples were similarly not contaminated with Cu and Ni, with concentrations below typical soil concentrations and the reported SGVs (Table 3).…”

Nursery Schools: Characterization of heavy metal content in indoor dust

“…The highest concentration heavy metal obtained was Fe with the mean concentration 4225.33 mg/kg and followed by Al with the mean concentration of 1229.58 mg/kg. Both Al and Fe are abundant elements in the Earth's crust (AlKhashman, 2004;Hunt et al, 2008). These elements have been produced by alteraction (friction) and distributed or transported via wind blow and can be associated with soil or street dust.…”

Indoor Residence Times of Semivolatile Organic Compounds: Model Estimation and Field Evaluation

“…For example, when considering removal by cleaning, Hunt et al found that mechanical cleaning did not completely remove SVOCs on surfaces because a significant portion of the compound was found in surface reservoirs such as carpet fibers or foam materials after a carpet vacuuming event. 13 Therefore, we use the term "non-mobile phase" to represent the portion of the compound partitioned into surface materials as opposed to the portion in dust or air.…”