Frequently asked questions
 What is this mapping tool?
How is this significant?
What is the source of the information?
How do I use this mapping tool?
How do I explore the data?
Where do the images in Google Earth come from?
What are the limitations of the mapping tool?
Can I compare the releases from different facilities?
How can I learn more about North American pollutant releases and transfers?
What is this mapping tool?
The North American Pollutant Release and Transfer Register (PRTR) mapping tool is a downloadable file that can be opened with the Google Earth mapping service to enable interactive mapping of almost 34,000 North American industrial facilities that reported on releases or transfers of pollutants in 2004. This mapping tool enables users to quickly find places of interest, identify nearby industrial facilities, and access detailed pollutant data for these facilities. [Top]
How is this significant?
This file creates a seamless map of PRTR reporting in North America. This is an unprecedented development in providing access to point-specific industrial pollutant data to any citizen in each of our three countries, and is of particular importance for people living in border regions. Until recently, only Canada and the United States had mandatory reporting requirements for industrial facilities. With the first year of mandatory reporting from Mexican facilities in 2004, a PRTR system that spans North America now exists. With this mapping tool, accessing pollutant data for specific industrial facilities is easier than ever before.
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What is the source of the information?
Facility names, addresses, and geographic coordinates come from each of the three North American countries’ separate PRTRs:
- the National Pollutant Release Inventory (NPRI) in Canada,
- the Registro de Emisiones y Transferencia de Contaminantes (RETC) in Mexico, and
- the Toxics Release Inventory (TRI) in the United States.
All of the data contained in the file are publicly available from the three countries’ environmental authorities: Environment Canada, Mexico’s Secretaría de Medio Ambiente y Recursos Naturales, and the United States Environmental Protection Agency.
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How do I use this mapping tool?
First, save the file (North America-PRTR-2004.kmz) to your computer. To view the file, you will need the Google Earth mapping service installed on your computer. Google Earth is a program that maps the earth using satellite images and aerial photography. You can download Google Earth at no charge from the web site http://earth.google.com/download-earth.html. Once you have installed it, launch Google Earth, then open the .kmz file by clicking File > Open from the task bar and selecting the file from the location on the computer where you saved it.
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How do I explore the data?
After you open the file with Google Earth, the contents will appear in the Places panel of the Google Earth window. The file contains folders with names of the three North American countries and their PRTR system (Canada – NPRI 2004, US – TRI 2004, and Mexico – RETC 2004). Inside each country folder are folders with the names of the states or provinces and territories within that country. Each of the state, province, and territory folders contains a list of the reporting industrial facilities. You can click to select the boxes next to the names of particular states, provinces, or territories to display the industrial facilities for those specific regions on the map, or you can click on the box next to the country name to display all facilities for that country. Double clicking on the state, province, or territory name (or expanding the respective folder by clicking the “+” sign) will display a list of all facilities in the Places panel.
Note: If you try to display all of the facilities from the United States at once, it is possible that no facilities or only a small cluster of facilities will be displayed until you zoom in to a specific area. Google Earth has an upper limit on the total number of placemarks that can be displayed at one time. Avoid this limitation by zooming in to a smaller region of the United States or by checking the boxes to display the facilities from a limited selection of states of interest within the US.
Use this map to find North American industrial facilities that reported pollutant releases or transfers. You can center the map image on your city, state, or province by entering its name in the Fly To tab in the Search panel of the Google Earth window. For the US and Canada, you can enter a street address, intersection, and zip or postal code in the Fly To tab. You can use the sliders to zoom in closer to your community, or you can zoom out for a wider view. Click on the placemarks for individual facilities for access to detailed information about the specific toxic chemicals released and transferred by that facility.
When you click on a placemark that identifies an individual facility on the map, an information balloon will appear with the facility’s name and address, along with a link to that facility’s report on the national PRTR web site (e.g., “NPRI 2004 report,” “TRI 2004 report,” or “RETC 2004 datos”). Clicking on the link will take you to that facility’s report within its respective country’s PRTR. The report contains detailed information about the facility and the types and amounts of toxic chemicals released or transferred.
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Where do the images in Google Earth come from?
The images are photographs taken by satellites and aircraft sometime in the last three years and updated on a rolling basis. As a result, you may notice differences with current features on the ground. Google Earth combines data of different resolutions to offer a seamless viewing experience, so some locations with only satellite imagery may look blurry if you zoom in close enough. However, Google Earth offers high resolution imagery for thousands of cities.
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What are the limitations of the mapping tool?
The file includes the reported locations of all facilities reporting to their countries’ PRTRs in the year 2004 that have associated geographic coordinates falling within national boundaries. Approximately 200 facilities are not included either because complete latitude and longitude data were not available or because the reported coordinates placed these facilities outside national boundaries.
The geographic coordinates for each facility are often self-reported by representatives of the facility and are subject to some error. Although in many cases the placemark will fall directly on the facility in the underlying Google Earth image, in other cases it may not. When the marker does not appear to fall on the facility, you may choose to copy the address of the facility—which is displayed when you click on the placemark itself —into the Fly To tab on the Search panel as an alternate method of locating the facility. Note that this technique will not work for Mexican facilities, since Google Earth does not currently support address lookup for Mexico.
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Can I compare the releases from different facilities?
This depends on a number of factors, such as what chemicals are of interest to you. Depending on their activities, facilities report releases of different substances. There are also some important differences among the reporting systems of the three North American countries. These differences include:
- which chemicals must be reported;
- which industries are required to report;
- which types of media (e.g., air, land, water) releases that are reported;
- criteria for reporting (e.g., the minimum amount of a substance released required for reporting, and a minimum number of employees at that facility); and
- different units of measurement (e.g., RETC and NPRI data are reported in metric units, while TRI data are reported in pounds).
The Commission for Environmental Cooperation of North America (CEC) provides “matched” data (i.e., a common set of chemicals and from a common set of industries) from the three countries’ PRTR systems as well as analyses of the data and trends over time on its web site Taking Stock Online . With the Taking Stock Query Builder, you can create reports that explore data from facilities, chemicals, industry sectors or geographic regions in the CEC matched data.
Keep in mind that PRTR data for an individual facility will not show you all potentially harmful substances that were released from the facility (only certain chemicals must be reported in each country), all sources of chemicals (only releases to certain media must be reported), or all releases and transfers of chemicals from a facility (only chemicals which meet particular thresholds are reported). Also, the facility data do not tell us about the environmental fate of the chemicals released, the risks from the chemicals released, or the levels of exposure of human or ecological populations to the chemicals.
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How can I learn more about North American pollutant releases and transfers?
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