United States Environmental Protection Agency National Risk Management Research Laboratory Research Triangle Park, NC 27711 Research and Development EPA/600/SR-97/004 March 1997 4>EPA Project Summary Development and Validation of a Method for Measuring Exempt Volatile Organic Compounds and Carbon Dioxide in Consumer Products E. E. Rickman, Jr., G. B. Howe, and R. K. M. Jayanty Ground-level ozone can cause a va- riety of adverse health effects as well as agricultural and ecological damage. Controlling emissions of volatile or- ganic compounds (VOCs) is important to reducing ground-level ozone; how- ever, not all VOCs are photochemically reactive and several have been ex- empted from control regulations. Cur- rently, there is no standard method for measuring the exempt VOC content of consumer products. This report de- scribes the development of such a method. The new method involves heat- ing a sample in an oven at 110°C for 1 hour while purging the sample con- tainer with nitrogen gas. The resultant mixture of nitrogen and volatile com- pounds from the sample is then col- lected in a Tedlar™ bag and analyzed by gas chromatography with mass se- lective detection (GC/MSD). An internal standard is added to the sample con- tainer to permit quantitation without measurement of the purge gas volume. The method was evaluated by analyz- ing samples that were spiked with known amounts of the exempt com- pounds. Recoveries of spiked com- pounds were excellent, ranging from 86% to 107% for the compounds and products tested. This method should be applicable to other volatile com- pounds that might be present in con- sumer products and could be useful in evaluating the risk that these products pose to the environment. This Project Summary was developed by EPA's National Risk Management Research Laboratory's Air Pollution Prevention and Control Division, Re- search Triangle Park, NC, to announce key findings of the research project that is fully documented in a separate report of the same title (see Project Report ordering information at back). Ground-level ozone can cause a variety of adverse health effects as well as agri- cultural and ecological damage. To con- trol the levels of ozone in the environ- ment, the U.S. Environmental Protection Agency (EPA) has established National Ambient Air Quality Standards (NAAQS) for ozone. In 1990, 98 areas in the coun- try did not meet the NAAQS for ozone, with over 150 million Americans living in these areas. VOCs are important contribu- tors to the formation of ozone in photo- chemical smog. Control of VOC emissions is an important strategy for controlling ozone levels. The 1990 Amendments to the Clean Air Act (CAAA) require EPA to conduct a study of VOC emissions from consumer products. However, there was no standard method for measuring the VOC content of consumer products. Such measurements are needed to assess the risk to the environment posed by VOCs in consumer products. Such a method will also be needed if EPA determines that the risk associated with VOCs in con- sumer products is sufficient to require con- trol regulations. To address the need for measurement of VOCs in consumer products, EPA has established a research program. This pro- gram has already produced results in four previous phases: ------- Phase I - Preliminary studies were performed on two candidate methods for VOC measurement (EPA Refer- ence Method 24 and Gravimetric Purge and Trap Gas Chromatogra- phy). Phase II - A Consumer Products Test Methods Work Group was established with participation from a number of state and federal agencies. This Work Group, after consideration of an initial list of 10 candidate methods, reached a consensus that further research should be concentrated on two meth- ods: EPA Reference Method 24 and Gravimetric Purge and Trap Gas Chromatography. Phase III - A test method was devel- oped to determine the total VOC con- tent of consumer products. This method was based on EPA Refer- ence Method 24, with added modifi- cations for sampling and analysis of consumer products. Phase IV - The test method devel- oped in Phase III was validated in an interlaboratory study. The validated total VOC method (Phase IV) for consumer products gravi- metrically measures the total volatile con- tent and determines the amount of water by gas Chromatography with thermal con- ductivity detection (GC/TCD). The water content is then subtracted from the total volatile content to calculate the total VOC content; however, many VOCs have been exempted from the list of regulated VOCs (40 CFR 51.100) due to their low photo- chemical reactivity and thus low ozone formation potential. Measurement of these exempt VOCs in consumer products would allow EPA to correct the total VOC mea- surements to better reflect the total ozone formation risk that consumer products pose to the environment. Upon examination of the exempt VOC compounds, only 12 compounds are rel- evant to consumer products. Carbon diox- ide, which is measured by the total VOC method, is also exempt and therefore is added to the target list shown in Table 1. Since it is anticipated that determining the exempt compound content will be con- siderably more expensive and time con- suming than measurement of total VOC content, a two-step approach to assess- ing the ozone formation risk posed by consumer products is envisioned. The first step would involve measurement of total VOC content for the product. Consumer products that might pose significant risks for ozone formation based on their total VOC content would then undergo a sec- ond step of having their exempt VOCs measured to provide a better assessment of their ozone formation risk. This report describes the development and validation of an exempt VOC measurement method that would be used as the second step of the VOC risk assessment process. The measurement method involves heating a sample in an oven at 110°C for 1 hour while purging the sample container with nitrogen gas. The resultant mixture of ni- trogen and volatile compounds from the sample is then collected in a Tedlar™ bag and analyzed by gas Chromatography with mass selective detection (GC/MSD). An internal standard is added to the sample container to permit quantitation without measurement of the purge gas volume. The method was evaluated by analyzing samples that were spiked with known amounts of the exempt compounds. Re- coveries of spiked compounds were ex- cellent, ranging from 86% to 107% for the compounds and products tested. Table 1. Exempt VOC Method Target List Compound Name Class II Ozone Depleting Chemicals0 carbon dioxidea methylene chloride (dichloromethane) 1,1,1,2-tetrafluoroethane (HFC-134a) pentafluoroethane (HFC-125) 1,1,2,2-tetrafluoroethane (HFC-134) 1,1,1-trifluoroethane (HFC-143a) 1,1-difluoroethane (HFC-152a) acetone tetrachloroethylene (perchloroethylene orperc)b chlorodifluoromethane (HCFC-22) 1,1,1-trifluoro 2,2-dichloroethane (HCFC-123) 1,1-dichloro 1-fluoroethane (HCFC-141b) 1-chloro 1,1-difluoroethane (HCFC-142b) 'Carbon dioxide is not a VOC, but ismeasured by the total volatilesmethod and hasbeen added to the target list to permit correction of measured total volatiles. bTetrachloroethylene was added to the exempt list during the course of this work (61 FR 4588, February 7, 1996). c Use of class II ozone-depleting chemicals (58 FR 65018, December 10, 1993) is currently restricted. These chemicals may be phased out in the future. ------- £. E. Rickman, Jr., G. B. Howe, and R. K. M. Jayanty are with Research Triangle Institute, Research Triangle Park, NC 27709. J. Kaye Whitfield is the EPA Project Officer (see below). The complete report, entitled "Development and Validation of a Method for Measur- ing Exempt Volatile Organic Compounds and Carbon Dioxide in Consumer Products," (Order No. PB97-143143; Cost: $21.50, subject to change) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Air Pollution Prevention and Control Division National Risk Management Research Laboratory U.S. Environmental Protection Agency Research Triangle Park, NC 27711 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati, OH 45268 Official Business Penalty for Private Use $300 BULK RATE POSTAGE & FEES PAID EPA PERMIT NO. G-35 EPA/600/SR-97/004 ------- |