PRTRs provide annual data on the amounts of pollutants released from a facility to the air, water and land and injected underground, as well as transferred off-site for recycling, treatment or disposal. PRTRs are an innovative tool for tracking certain chemicals, thereby helping industry, governments and citizens identify ways to reduce the release and transfer of these substances, increase responsibility for chemical use, prevent pollution and cut back on waste generation.

Because of national PRTR reporting requirements, including thresholds for pollutants and facilities, only a portion of all industrial pollution is being captured. Also, industrial facilities are not the only sources of pollution in North America. Using and Understanding the Data

By tracking information on releases and transfers of individual pollutants, PRTR data are an important tool that can help industry, governments, communities and non-governmental organizations identify pollution prevention and reduction opportunities. The CEC's NAPRTR Project adds value to national PRTR data by offering enhanced data access and analyses at the North American scale in recognition of the fact that pollution reduction efforts require collaboration across borders Ongoing Activities of the CEC's NAPRTR Project

Substances released or transferred by industrial facilities have physical and chemical characteristics that influence their ultimate disposition and consequences for human and ecological health. Assessing the potential harm from particular releases of a pollutant to the environment is a complex task because the potential of a substance to cause harm arises from various factors, including its inherent toxicity and the nature of the exposure to the substance (e.g., the potential risk posed by asbestos sent to a secure landfill is considered to be much lower than the risk posed by asbestos released to air). Using and Understanding the Data

PRTR data provide important, but not all, information about pollution in North America. Also, industrial facilities are not the only sources of pollution in North America. Many questions need to be answered in order to establish realistic pollution trends, including: Did production at some facilities stop for part of the year, or was the amount of a pollutant handled at the facility below the reporting threshold that year? Did the same facilities report throughout the entire period being analyzed? Did the number of pollutants subject to PRTR reporting change over this period? And so on.

Many of the substances reported by industrial facilities across North America relate to specific problems including: Toxicity; Smog; Climate Change; Safe Drinking Water; Long-Range Pollution; Thinning of the Ozone Layer.

Toxicity

Some of the reported pollutants are persistent, bioaccumulative and toxic. Persistent substances are slow to break down and can continue to circulate in the environment for many years. Pollutants that are bioaccumulative can be readily taken into fish or animals and can accumulate over time in fatty tissue. Pollutants can also be toxic due to their potential carcinogenicity or for causing developmental or reproductive harm.

Smog

Some of the substances reported to PRTRs can contribute to smog. Ground-level ozone, one of the main components of smog, is often produced when volatile organic compounds (e.g., methanol and benzene) and nitrogen oxides (a criteria air contaminant) react in the presence of sunlight. Other sources, such as vehicle emissions, incinerators and evaporation from gasoline, solvents and paints, also release volatile organic compounds CAC/GHG

Climate change

The build up of gases such as carbon dioxide, nitrous oxide and methane in the atmosphere can contribute to climate change, through the greenhouse gas effect. These gases are not currently reported to NPRI or TRI but some are included in the Mexican RETC. Other sources of information on greenhouse gases exist in each country CAC/GHG

Safe Drinking water

Some of the pollutants covered in Taking Stock are subject to standards or guidelines that prescribe the maximum allowable concentration of the substance in drinking water. The data in this report describe the total amount of a substance released from each facility into the water over a year. They could be used to identify chemicals that need to be monitored in a lake or river that feeds a drinking water plant, but they would not provide good estimates of drinking water quality. See the Taking Stock feature analysis of pollutant releases to water.

Long-range pollution

Some of the reported pollutants can travel large distances through the "grasshopper effect." A pollutant evaporates, travels with the wind and is deposited, only to be evaporated, carried again and re-deposited, often hundreds of miles from its source. For example, some substances deposited in the ecologically sensitive Arctic have been released thousands of miles away.

Thinning of the ozone layer

Releases of certain chemicals such as CFCs and HCFCs can contribute to the thinning of the ozone layer in the upper atmosphere, which shields life on earth from the sun's harmful ultraviolet radiation. Less protection from ultraviolet light will, over time, lead to higher incidence of skin cancer and cataracts and increased crop damage.