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Responses about the features of the houses held few surprises, according to the questionnaire responses in 􏰀able 􏰁 below􏰂 􏰃earl􏰄 􏰅􏰆 percent ha􏰇e a crawlspace, but they are not uniformly distributed around the country􏰂 􏰈bout the same percentage 􏰉􏰅􏰊􏰋􏰌 ha􏰇e attached garages, with the majority distributed between the occasional detached garage and a lack of a garage. 􏰍ield e􏰎perience by one of the authors has identi􏰏ed crawlspaces and attached garages as frequent sources of contamination. Exposure occurs when contamination migrates into the living space through air pathways via pressure differentials generated by temperature gradients or wind.
􏰐erhaps the more signi􏰏cant feature impacting the health of occupants and the need for cleaning proto􏰑 cols, according to preliminary analysis, is the preva􏰑 lence of older wall􏰑to􏰑wall carpeting in bedrooms. 􏰀he combination of the friability of deteriorated carpets and the attempts to keep carpeting clean by vacuuming can be a major source of particle pollution. The physical action of vacuuming carpets, especially with the use of motori􏰒ed powerheads, aerosoli􏰒es particles directly from the carpet outside of the range of the in􏰓ow of air. This, along with inadequate 􏰏ltration of the vacuum exhaust, can dramatically increase the airborne spread of dust and subsequent accumulation on surfaces.
Dust - An Introduction
Dust was not an initial concern with the original development of the questionnaire. There were only
two questions about dust with a minor curiosity about whether internal sources of dust could be differentiated from external sources. 􏰔ne question asked about dust generally on interior surfaces and the other was speci􏰏cally for dust on window sills. 􏰈s the initial analysis of the overall data developed, associations with the reported presence of dust began to appear.
This unanticipated emergence of a relatively minor question took on new meaning when considered along with medical 􏰏ndings into the role of dust as a
signi􏰏cant factor in human health.
􏰕isible particles of dust are not the only issue. Dust is
composed of agglomerations of subvisible particles and can be a vector for molecular substances. Laboratory characteri􏰒ation of ordinary 􏰖house dust􏰗 samples, for example, are able to identify as many as 200 substances detectable by microscopy. The substances can range from the familiar dirt and sand to mold spores and fragments, pollen, pet and other animal dander, plus the ubiquitous human skin cells. Fragments of plant leaves or 􏰓owers and stems are common, as is carbon black, char, and other combustion products from highway traf􏰏c, house 􏰏res, and the increased prevalence of wild􏰏res. 􏰘eavy metals, automobile brake dust, diesel particles, pesticide residue, construction dust, paint particles, asbestos, and particles of lead􏰑based paint can also be found in ordinary house dust.
Implications for known or suspected health effects from dust inhalation have taken on an increased
2, 3, 4, 5, 6
8/16/2021
Census Bureau - Regions
Overall
Midwest
Northeast
South
West
Canada
Housing characteristics
N
55,498
12,917
8,196
22,133
11,713
538
attached garage
31.8%
35.7%
28.4%
28.7%
35.4%
36.8%
attic
49.2%
54.1%
49.7%
51.0%
40.1%
49.1%
basement
34.5%
61.0%
68.6%
14.3%
17.6%
69.5%
crawlspace
29.3%
25.9%
18.1%
32.8%
34.9%
15.4%
ERV/HRV
3.0%
3.1%
2.6%
2.8%
3.1%
18.0%
fireplace
37.3%
35.2%
33.1%
37.5%
41.7%
47.6%
air purifiers
16.3%
16.5%
18.9%
14.2%
18.1%
21.7%
carpet in house
34.2%
44.3%
29.8%
29.1%
36.8%
13.0%
carpet in bedroom
28.7%
26.3%
23.6%
31.0%
31.0%
21.2%
carpet age years
10.7
10.8
11.6
10.4
10.4
13.4
Table 1. Percent reported Housing Characteristics by Geographic Region (Note: Responses to some questions may have overlapped resulting in inconsistent data (such as houses with carpet in bedrooms are reported as greater than houses with carpet in the South and Canada.)
FALL 2022 THE JOURNAL OF CLEANING SCIENCE | 27