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Principal Investigator: William W. Nazaroff
University of California, Berkeley
April 2006
ARB Contract No. 01-336 (Full Report)
ABSTRACT
When cleaning products and air fresheners are used
indoors, occupants are exposed to airborne chemicals, potentially
leading to health risks. Indoor air pollutant exposures owing to
cleaning product and air freshener use depend on emissions from
products, dynamic behavior of chemical species, and human factors. A
series of experiments was conducted to investigate volatile organic
compound emissions, concentrations, and reactive chemistry associated
with the household use of cleaning products and air fresheners.
Research focused on two common classes of ingredients in cleaning
products and air fresheners: ethylene-based glycol ethers, which are
classified as toxic air contaminants, and terpenes, which react rapidly
with ozone. A shelf-survey of retail outlets led to the selection of 21
products whose chemical composition was characterized. Among the
criteria used to select these products were ready availability through
California retail outlets and, for the majority of products,
expectation that they contained ethylene-based glycol ethers, terpenes
and related compounds, or both. Of the 17 cleaning products
characterized, four contained substantial levels of d-limonene (4-25%
by mass), three contained terpenoids that are characteristic of pine
oil, six contained substantial levels of ethylene-based glycol ethers
(0.8-10% by mass), and five contained less than 0.2% of any of the
target analytes. Xylene in one product was the only other toxic air
contaminant detected. Among the four air fresheners characterized,
three contained substantial quantities (9-14% by mass) of terpene
hydrocarbon and terpene alcohol constituents, with linalool being the
most abundant. Six of the 21 products were investigated in
simulated-use experiments in which emissions and concentrations of
primary constituents were measured. Cleaning products that contain 2-
butoxyethanol as an active ingredient produced one-hour-average
concentrations of 300 to 2,300 µg/m 3 immediately after simulated
typical use in a room-sized chamber. For cleaning products that contain
d-limonene as an active ingredient, corresponding levels were 1,000 to
6,000 µg/m 3 . Application of a pine-oil based cleaner produced
one-hour-average concentrations of 10-1300 µg/m 3 for terpene
hydrocarbons and terpene alcohols. Reactive chemistry was studied by
exposing constituents of three products to ozone, both in a bench-scale
chamber and during simulated use. Prominent products of the reaction of
terpenes with ozone included formaldehyde (a toxic air contaminant),
hydroxyl radical, and secondary organic aerosol (a form of fine
particulate matter). Incorporating the new experimental data, exposures
were estimated for several simulated use scenarios. Under ordinary
circumstances, exposures to 2-butoxyethanol, formaldehyde, and
secondary organic aerosol are not expected to be as high as guideline
values solely as a result of cleaning product or air freshener use.
However, ordinary use could lead to exposure levels of similar
magnitude as guideline values. Scenario model results suggest that
exposure levels could exceed guideline values under exceptional yet
plausible conditions, such as cleaning a large surface area in a small
room. The results of this study provide important information for
understanding the inhalation exposures to certain air pollutants that
can result from the use of common household products.
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