In order to evaluate the total amount of perc emissions that could be reduced by the dry cleaning industry moving to more green processes, it is necessary to begin building a national inventory of dry cleaning-based perc emissions. In order to create a national inventory, you must gather baseline data of the dry cleaning industry in your geographic area. Important questions to consider are:

• How many dry cleaners are in your area?
• How much solvent do they use (size)? How often?
• What types of chemicals (solvents) do they use?
• Estimate the environmental impact of the dry cleaning industry in your area.

Dry cleaning is a heavily regulated industry. All dry cleaners must keep monthly records about the amount of perc they purchase and submit an annual report to their local regulating agency. This agency might be a city agency that sends the reports to a state agency (who then submits the reports to a federal agency, in this case the Environmental Protection Agency). In some cases (like very rural areas) the facility sends their report directly to the state agency.

All of the information contained in these reports is public knowledge. Because of this, it is possible to determine the total amount of perc emissions in a given area using the Internet.

Step 1: Access EPA AirData: Access the Environmental Protection Agency's AirData webpage at the following url: http://www.epa.gov/air/data. This page can be explored in order to learn more about the EPA's AirData program. The "info" link is a good resource providing easy reference as participants build their dry cleaning emissions inventory.

The introduction screen is shown below. From this screen choose the "Reports and Maps" link. From this link, select the "Select geographic area"

Step 2: Select Geographic Area: On this page, you will select the exact geographic area that you want to develop your inventory for. The inventory is being created on a county basis, so you will need to select the desired county. This can be done by selecting state and county (see following figure) or by selecting MSA (better for metropolitan areas) and selecting county on the following screen.

Dry cleaners operate differently than many storefront industries. Small, independent dry cleaners operate from one single location. Clothes are dropped off, cleaned, and picked-up from the same location. Larger firms (like the "McDonald's" of dry cleaners) utilize satellite locations for clothing drop-off and pick-up. The clothes are transported to a large, central location where they are actually cleaned: only the locations where cleaning occurs have reported emissions. Because of this, it is likely that some counties that have dry cleaning storefronts will not have any reported facilities. You may need to inventory several surrounding counties to completely assess your area in order to account for clothes that are transported and cleaned outside of the county in which they were dropped-off. County searches that result in zero facilities are still a viable result and should be submitted like any other data collection submission. Selecting the best geographic area for your inventory will require some trial and error and/or a compilation of several different searches. Once the appropriate search constraints have been selected, click on the "Go" button.

Step 3: Specify Report Type: Perc (tetrachloroethylene or perchloroethylene) is a hazardous air pollutant. In order to generate your local inventory, it is necessary to select a report format that gives emissions data for hazardous air pollutants emitted by industrial facilities. The appropriate link is highlighted below. Additional report formats are described in the bottom half of the page (not shown here).

Step 4: Select Pollutant: Scroll through the pollutant list and select tetrachloroethylene (i.e. perc or perchloroethylene) from the "pollutant emitted" window. This page allows the user to select various properties for the report format (numeric notation, lines per page, etc.). Please select the options that best meet the magnitude of your specific search. Once the appropriate specifications have been made, click on the "Generate Report" button.

Step 5. View Report: The generated report will contain an itemized list of facilities that have known perc emissions. While dry cleaning accounts for a majority of these facilities, perc is used as a solvent by many other types of facilities. Metals cleaners, the chemical industry, and even the construction industry all use perchloroethylene. Because of this, it will be necessary to edit the generated report so that dry cleaners are the only industry present. Most dry cleaners have the word "cleaner" in their name. Other perc users will tend to be larger companies, so making the distinction should not be too difficult. If you are unsure about a facility, looking at the "Facility Details" for a particular facility will show all of the regulated pollutants for a given facility. Dry cleaners will, generally, only have one regulated pollutant (perc), whereas construction companies and chemical companies might have many regulated pollutants, but this is not always the case. Beware with these assumptions: there are always exceptions. Dry cleaners that also perform leather and/or fur cleaning services will use more than one solvent for these purposes. It is always possible to query between the report and a local phone book should a question with a specific facility arise.

Report Variables: The most important variables and their descriptions from the report are listed below.

Location markers: important variables that will be used to "track" the data in the national inventory are location markers. These include:
• State
• County
Facility Markers: These variables help designate the individual facilities and geographic/demographic designation of each.
• Urban/Rural Designation
• Facility Name
Emissions Data:
• Pollutant emissions - the number of pounds/year for perc (tetrachloroethylene or perchloroethylene) emitted to the atmosphere by each facility
• % of Total Emissions - the % of the report's emissions (i.e. the selected county's) that can be attributed to that facility

The actual generated report can be copied and exported to Excel, where it will be much easier to work with.

Step 6. Data Assessment: Once the report has been imported into Excel, it is possible to begin manipulating the data. The dataset can be greatly reduced, since the only information needed for each county in the national inventory is county, state, number of dry cleaning facilities, total pounds of perc emitted atmospherically per year, and the total percentage of all perc atmospheric emissions this number accounts for within the county. Basic Excel functions will allow you to calculate the pollutant variables for each county (see example below). These data points can then be submitted online through the data submission portion of this section.