Volatile Organic Compounds present in Common Household Air Fresheners
Daniel Powell, Dr. Bernard Crimmins, Dr. Philip Hopke
Center for Air Resources Engineering and Science, Clarkson University
Ambient particulate matter is composed of a variety of species, including sulfate, nitrate, elements and carbonaceous material. The carbonaceous particulate matter is composed of hundreds of individual components (Rogge et al 1993) with both primary (diesel exhaust,
biogenic emissions) and secondary sources. Secondary sources stem from reactions of VOC precusors. These VOCs are emitted from a variety of sources including, vehicles and plants which are oxidized to form compound that condense on to existing particulate matter and/or form new particles via nucleation.
The oxidation of VOC precusors can also form species that are toxic. For example, formaldehyde is a compound thought to be formed as a SOA product and is believed now to be a carcinogen. (Nazaroff and Weschler et al., 2006)
Reactive VOC’s have been found in indoor air which may serve as precusors for SOA formation indoors. Air fresheners are believed to be a significant source of certain Volatile Organic Compounds (VOC’s) such as terpenes that have been shown to form SOA (Singer et al., 2006). These products may be persistent due to poor ventilation or secondary products binding to furniture and carpet. These factors could lead to chronic exposure to these species.
The goals of this study were to identify compounds emitted from commercially available air fresheners. From these experiments each constituent was evaluated for their SOA formation potential indoors. Ozone readily reacts with the double bonds therefore compounds with these moieties were considered potential SOA precursors (Fan and Lioy et al., 2003).
Off the shelf air fresheners purchased locally were evaluated. Several brands including, Renuzit, Glade, Febreze, and Air Wick were examined as well as a variety of scents from each manufacturer. Each air freshener was transferred into a 40 mL vial with Teflon cap. The samples were then allowed to equilibrate at least 12 hours. Liquid samples were then heated to 60°C simulating how they would be used in a home. A 1mL syringe was used to sample the headspace of the vials which was then introduced to the GC/MS by direct injection. VOC’s were identified by Gas Chromatography/Mass Spectroscopy (GC/MS) using a Finnigan Trace GC ultra with a Finnigan Polaris Q MS. The samples were introduced with splitless injection and resolved using a 30m x 0.25mm DB-5MS capillary column and ionized by electron ionization. The GC initial temperature was 35°C. The oven was then ramped at 2°C/min to 100°C, followed by a second ramp of 15°C/min to a max temperature of 275°C and held for 10 minutes. The mass spectra of the resolved peaks were identified using a NIST spectral library (National Institutes of Science and Technology). Identification of the respective molecules were based on the relative probability of each match generated by the program.
Compounds identified as potential SOA precursors will be discussed. Comparisons will be made within and among brands analyzed.
References:
Destaillats, H., Lunden, M.M., Singer, B.C., Coleman, B.K., Hodgson, A.T., Weschler, C.J., and Nazaroff, W.W. 2006. Indoor Secondary Pollutants from Household Product Emissions in the Presence of Ozone: A Bench Scale Chamber Study. Journal of Environmental Science and Technology 40, 4421-4428.
Fan, Z., Lioy, P., Weschler C., Fiedler N., Kipen, H., and Zhang, J. 2003. Ozone-Initiate Reactions With Mixtures of Volatile Organic Compounds under Simulated Indoor Conditions. Journal of Environmental Science and Technology 37, 1811-1821.
Rogge, W.F., Mazurek, M.A., Hildemann, L.M., Cass, G.R., Simoneit, B.R.T. 1993. Quantification of urban organic aerosols at a molecular level: Identification, abundance and seasonal variation. Atmospheric Environment 27, 1309-1330
Singer, B.C., Coleman, B.K., Destaillats, H., Hodgson, A.T., Lunden, M.M., Weschler, C.J., Nazaroff, W.W. 2006 Indoor Secondary Pollutants From Cleaning Product and Air Freshener Use In the Presence of Ozone. Atmospheric Environment 40, 6696-6710.
Singer, B.C., Destaillats, H., Hodgson A.T., Nazaroff W.W. 2006. Cleaning Products and Air Fresheners: Emissions and Resulting Concentrations of Glycol Ethers and Terpenoids. Indoor Air 16, 179-191.