# Presentation: 893900

## Reducing Chemical Exposure to School Children through the Buy Clean Initiative

- Zhishi Guo, D. Bruce Henschel, and Kenneth A. Krebs
- U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory
- Research Triangle Park, NC 27711

- The overarching science question is how the environmental health risks to susceptible subpopulations can be mitigated.  This study focuses on the mitigation of chemical exposure to school children by addressing the following questions.  How can the indoor air quality in schools be improved by identifying and eliminating pollution sources?  What hazardous chemicals, including volatile organic compounds (VOCs), are contained in commonly used school supplies and should be avoided?  How can school managers select products and services with lower health risks to school children?

**Research Goals**

**Methods and Approach**

**Impact and Outcomes**

**Results and Conclusions**

**Future Directions**

**Science Question**

- Chronic inhalation exposure to hazardous chemicals is one of the factors that may exacerbate respiratory diseases and other health problems in school children.  EPA’s National Buy Clean Program is a partnership with key stakeholders to promote the purchasing of products and services for healthy indoor environments in schools. This study supports the Buy Clean Initiative by identifying high risk products, characterizing the pollutant emissions, and developing models and databases. The short-term goal is to provide practical advice and tools to school managers to reduce the health risk to children; the long-term goal is to develop a broadly applicable set of tools and models that can be routinely used  to evaluate alternatives for commercial products used in schools.

***Hazardous Chemicals in Hard-Surface Cleaners***
- A total of 267 MSDSs were collected from various sources.  Eighty-one of them were for all-purpose cleaners, 39 for disinfectants, 26 for glass cleaners, 64 for degreasers, and 57 for toilet bowl cleaners.  These products were made by 56 manufacturers.  A total of 151 chemical ingredients, excluding water, are reported in the MSDSs.  Most are individual chemicals, but a few represent mixtures (e.g., pine oil) or a group of chemicals.  Forty-four out of the 151 chemicals are considered either volatile or semi-volatile. Of major concerns are hazardous air pollutants (HAPs), other irritants, and formation of potentially hazardous secondary air pollutants.
- The HAPs listed in the MSDSs include ethylene glycol monobutyl ether (i.e., 2-butoxy ethanol), diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, hydrogen chloride (as gas), and methanol.  The combined number of occurrences for HAPs is 86 out of the 267 cleaners. Products containing high concentrations of these chemicals, especially the glycol ethers and hydrochloric acid, should be avoided.  In addition to these HAPs, many other chemicals may cause irritation or affect central nerve systems.
***Development of a Screening-level Model for Hard-Surface Cleaners***
- Chemical emissions from an aqueous solution is controlled by Henry’s law and overall mass transfer coefficient.  A major difficulty in predicting the chemical emissions from water-based cleaners is the presence of surfactants, which may reduce Henry’s constant significantly.  This effect is especially significant for less soluble chemicals.  The primary model that was developed in this project (the film model) is a simplified source model that predicts the emissions of volatile, organic and inorganic chemicals from a thin film of water-based cleaner applied to a hard surface.  This model has two forms: Eq. 1 gives the pollutant concentration as a function of time, and Eq. 2 gives the time-averaged concentration.
- where  Ct = pollutant concentration at time t (mg/m3); Cavg = average pollutant concentration between time 0 and t (mg/m3);  N = ventilation rate (h-1); W0 = amount of cleaner applied to the surface (g);
-              y0 = content of volatile chemical in the cleaner (mg/g); V = room volume (m3); S0 = initial area of the cleaner film (m2); kw = gas-phase mass transfer coefficient for water evaporation (m/h);
-              Cw0 = saturation concentration of water vapor (g/m3); and RH = relative humidity in the room (fraction).

- Although asthma and other respiratory diseases in school children can be triggered or exacerbated by many factors, indoor air quality has shown the strongest link thus far.  One way to improve indoor air quality is to eliminate the pollution sources. This project supports OPPTS, Office of Radiation and Indoor Air, and Regional Offices’ efforts to implement the Agency's Buy Clean Initiative by identifying high risk products used in schools and by providing practical advice to school managers to reduce the health risks to children.  The major research results will be presented in April at the Agency’s Schools Workgroup meeting, where both program and regional offices have representatives. It is anticipated that we will work with a regional office to implement the product selection strategy for hard-surface cleaners in some schools. In collaboration with OPPT, ways to integrate the research results into the Agency’s Tools for Schools package will be identified, evaluated, and implemented.

- Evaluation of water-based hard-surface cleaners was completed in 2004. Testing of erasable markers and cleaning liquids will be completed in late 2005.  Practically useful advice for selecting less hazardous markers will be provided to schools through the Agency’s program and regional offices.  While evaluation of other high risk products will continue in the near future, more research attention will be given to the development of broadly applicable risk management strategies for schools.

**References**

- OEHHA (2004),  All Chronic Reference Exposure Levels Adopted by OEHHA as of August 2003, Office of Environmental Health Hazard Assessment, California, 2004.  Available at http://www.oehha.org/air/chronic_rels/AllChrels.html.
- U.S. EPA (2004),  Integrated Risk Information System, U.S. Environmental Protection Agency, Washington, D.C.  Available at:  http://www.epa.gov/iriswebp/iris/index.html
- U.S. EPA (2005), *Potential Inhalation Exposure to Volatile Chemicals in Water-based Hard-surface Cleaners*, EPA/600/R-05/005, National Risk Management Research Laboratory, Research Triangle Park, NC (in press).
- WHO (2001),  *Air Quality Guidelines for Europe*, 2nd ed.  WHO Regional Publications; European Series, No. 91. World Health Organization, Copenhagen, Denmark.

- The EPA Source Ranking Database (SRD), developed by the Office of Prevention, Pesticides and Toxic Substances (OPPTS), was used to generate a list of candidate products used in schools for further screening. Final selection of high risk products was made in consultation with OPPTS and other program offices.  Water-based hard-surface cleaners and erasable markers were the first two products selected. Evaluation of a product included three steps: (1) identify potential hazardous chemicals present in the product category and determine their contents; (2) characterize the chemical emissions under close-to-realistic conditions by testing typical products in environmental chambers or research test house, and (3) develop tools (e.g., models and databases) for school managers to select less hazardous products.
- Material Safety Data Sheets (MSDSs) were used to identify hazardous chemicals in hard-surface cleaners. Emissions testing was conducted in 53-liter and 30-m3 environmental chambers (Figs 1, 2) in which the temperature, humidity, ventilation rate, and air velocity can be controlled.  The data were used to develop a simple, screening-level model for product selection based on potential health effects (U.S. EPA, 2005).
- Identification of hazardous chemicals in erasable markers and cleaning liquids was conducted by headspace and formulation analyses. Experiments are being conducted under simulated real use conditions by using breathing manikins to determine the solvent exposure to school children as well as the exposure to nearby occupants in the area where these markers are in use.

***Model Evaluation with Chamber Data***
- Model predictions were compared with 11 sets of chamber data generated in the 53-liter and 30-m3 environmental chambers.  Results showed that the average predictive error was 12.6% for the 4-hour average concentration and 37.1% for the peak concentration. Fig. 3 shows an example of the model prediction vs experimental results. It is recommended that the time-averaged concentration be used for product screening. The values of the parameters in this model can be easily obtained by the user, and the model can be readily utilized through a spreadsheet program. In addition to VOCs, it can also be applied to volatile inorganic compounds such as hydrogen chloride and ammonia.
***Using the Model as a Tool for Product Comparison***
- One approach for using this model in such a screening manner could involve the following steps: (1) Using Eq. 2 to calculate the time-averaged (2-, 4-, or 8-h) exposure concentrations for the individual VOCs in each of the cleaners to be compared.  (2) Select the health-based concentration guideline to be used in making the comparison.  One choice could be the Reference Concentration (RfC) published by EPA (EPA, 2004). Other options could be the European guidelines (WHO, 2001) or Reference Exposure Levels (RELs) for chronic inhalation set by California’s Office of Environmental Health Hazard Assessment (OEHHA, 2004).  (3) Divide the calculated time-averaged concentration (from the first step) by the health-based guideline selected in the second step.  This ratio might be considered an “inhalation exposure index” (IEI). (4) The cleaner product having the lowest IEI would, by implication, offer the lowest health risk, insofar as can be judged with the effects data available at present.

- Fig.3 Predicted vs observed 2-butoxy ethanol concentration for     a hard-surface cleaner applied to counter-top laminate

- Fig. 1 NRMRL large chamber facility

- Fig. 2 NRMRL small chamber lab