|When cleaning products and air fresheners are used
indoors, occupants are exposed to airborne chemicals, potentially leading to health risks. These exposures 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 these products: 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.
Products were selected based on widespread availability in California retail outlets and, for the majority of products,
expectation that they contained ethylene-based glycol ethers, and/or terpenes. Of the 17 cleaning products characterized,
four contained substantial levels of d-limonene (4-25% by mass), three contained terpenoids 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. Among the four air fresheners characterized, three contained substantial
quantities (9-14% by mass) of terpenes (hydrocarbons and alcohols), 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/m3 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/m3. Application
of a pine-oil based cleaner produced one-hour-average concentrations of 10-1300 µg/m3 for terpenes.
Reactive chemistry was studied by exposing constituents of three products to ozone, both in a bench-scale chamber
and during simulated use. These reactions result in the formation of formaldehyde (a toxic air contaminant), hydroxyl
radical, and secondary organic aerosol, which is initially formed as ultrafine particles (less than 100 nanometers
in diameter). The experimental data was used to estimate exposures associated with typical product use. Ordinary
scenarios of cleaning product and air freshener use can lead to exposures to 2-butoxyethanol, formaldehyde, and
secondary organic aerosol that are of similar magnitude to guideline levels, based solely on product emissions
and not considering other sources. 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.
|Brett Singer, Ph.D., is a Staff Scientist in the Atmospheric Sciences and Indoor
Environment Departments of the Environmental Energy Technologies Division of Lawrence Berkeley National Laboratory.
Dr. Singer works broadly in the field of air quality research, with specific expertise in the measurement of pollutant
emissions, characterization of pollutant dynamics in real and simulated indoor environments, emission inventory
development, and air pollutant exposure analysis. Dr. Singer earned a Ph.D. from the U.C. Berkeley Civil Engineering
Department's Environmental Engineering Group in 1998. His dissertation research focused on the development of new
approaches to quantifying on-road motor vehicle emissions.
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