Here we discuss data on human-made potentially harmful emissions that are collected or estimated at the point of release into an environmental medium (land, water or air).  Below are the major types of sources as defined by the U.S. Environmental Protection Agency and the Pennsylvania Department of Environmental Protection (PADEP) for one major type of pollutant, Hazardous Air Pollutants, or HAPs.  For other types of pollutants, the amount thresholds may vary but definitions and examples are similar.  The source type for which the most information available is major point sources, but as Figure 2 illustrates, these may account for only one-fourth of all human-made potentially harmful air emissions.


Figure 2: Major Categories of Hazardous Air Pollutant (HAP) Sources[49]

Source type[50]



EPA estimated % of total human-made Hazardous Air Pollutants[51]

Major point

Stationary sources “that emit or have the potential to emit at least 10 tons per year of any one HAP, or at least 25 tons per year of a combination of HAPs.”[52]

power and chemical plants, refineries, large waste combustors



Stationary sources that “emit less than 10 tons per year of a single HAP and less than 25 tons per year of all HAPs combined… Though emissions from individual sources are often relatively small, collectively their emissions can be of concern.”

gas stations, dry-cleaners, print shops, autobody shops, furniture manufactures, wood stoves, pesticides, and home cleaners



See examples. “Mobile sources produce air toxics through tailpipe emissions as well as evaporation from the engine, the fuel system, and when refueling.”

cars, trucks, buses, boats, trains, lawn-mowers, tractors and recreational vehicles



Point Sources: Toxic Release Inventory (TRI)

Because the Environmental Protection Agency’s nationwide Toxic Release Inventory (TRI) is by far the most comprehensive source of information for point source releases, we cover it in some depth here.

Overview of Major Pollutant Categories

Section 313 of the EPCRA (Emergency Planning and Community Right to Know Act) mandated establishment of the Environmental Protection Agency’s (EPA’s) Toxics Release inventory (TRI).  The TRI contains nationwide information on approximately 650 different chemicals released by a number of industry sectors.[54]

In the case of air pollution, for example, the EPA divides pollutants into several categories depending upon whether they are known to be of particular hazard to a large number of people, and whether federal legislation declares they must be regulated.[55]  These major categories are as follows:

·         Hazardous Air Pollutants (HAPs): The Clean Air Act defined 188 pollutants or air toxics associated with various adverse health effects including cancer.[56]  Note that the term “toxic pollutants” or “air toxics” is often used in lieu of HAPs, and may include other chemicals beyond HAPs, but does not include Criteria Pollutants.  (One source of confusion is that Criteria Pollutants are still included in the Toxic Release Inventory, despite the latter’s name.)

·         Urban Hazardous Air Pollutants (Urban HAPs): This is a subset of 32 of the 188 HAPs determined to “present the greatest threat to public health in the largest number of urban areas,” plus diesel particulate matter.[57]

·         Criteria Air Pollutants: Separate from the HAPs[58] are six principal pollutants defined by the federal Clean Air Act for monitoring and regulation, which are common throughout the U.S.: carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter and sulfur dioxide (locally, the Allegheny County Health Department and the PA Department of Environmental Protection monitor these pollutants).  Particulate matter, which includes components of diesel exhausts, is described in more detail under Environmental Monitoring: Air.  Ozone is not directly emitted, but forms when other emissions react in sunlight; and PM can either be directly emitted or formed when other gases react in the atmosphere.[59]

·         Substances facilitating criteria air pollutants: The EPA also collects emissions data for three substances that are considered precursors of criteria air pollutants: volatile organic compounds (VOCs), nitrogen oxides (NOx), and ammonia (NH3).[60]

·         Persistent, Bioaccumulative and Toxic Chemicals (PBTs):  These 16 chemicals and 4 chemical compounds, including lead, mercury, and dioxin-like compounds, “are of particular concern not only because they are toxic but also because they remain in the environment for long periods of time, are not readily destroyed, and build up or accumulate in body tissue.”[61]


Sites reporting under TRI regulation include facilities with a) a size and production amount triggering reporting requirements, and b) a Standard Industrial Classification (SIC) Code of 10, 12, 20-39, 49 or 51;[62] or any SIC code if it is a federal facility.[63]  TRI data, collected by the EPA and states and reported annually, include business reports of locations and quantities of chemicals stored on-site, data on transfers and releases of certain chemicals from industrial facilities, and data on waste management and source reduction endeavors (including amounts of each chemical recycled, treated, or combusted for energy recovery).  Within Allegheny County, a number of sites report emissions estimates online to the Allegheny County Health Department (ACHD), which then submits it to the EPA.[64]  Facilities must report releases from both routine processing and accidents.  Methods of release reported include discharges into air,[65] surface water and land; transfers to off-site locations (including amount and destination); and underground injections both on-site and off-site.[66], [67]

The TRI 2003 reporting year[68] data available at the EPA website include information on 1,329 sites for PA, 283 for the 10-county Pittsburgh region,[69] and 88 sites for Allegheny County.[70]  As outlined in Figure 3 below, sites within the 10-county region reported nearly 87 million pounds of releases and on- and off-site disposal in 2002, with Beaver, Armstrong and Allegheny counties accounting for nearly four fifths of the regional total.[71]  Keep in mind, however, that these data still exclude many area and mobile sources—and that in some cases, a single source may represent a large proportion of a county’s total.[72]


Figure 3: Number of Sites Reporting Point Source Releases to the TRI, and Total Releases Reported, Pittsburgh Region by County (2002 and 2003)[73]



Sites Reporting to TRI, 2003

Total Releases & Disposal Reported (lbs.), 2002































Region Total





Below we review the strengths and weaknesses of the TRI that we have noted through our investigation so far.

Strengths of the TRI[74]

·         TRI data are “multi-media,” requiring facilities to report releases to air, water, land, underground and off-site locations separately.[75]

·         Facilities are subject to fines of up to $27,500 per day if they fail to report releases by July 1 of each year; the data are also required by federal law to be publicly available.[76]

·         The EPA has increased measurement accuracy and/or lowered the reporting thresholds for certain PBTs (persistent, bioaccumulative and toxic chemicals), such as lead and dioxin.[77]

·         EPA requires reporting of releases in pounds, rather than concentrations or volumes, which can be difficult or impossible to convert.

·         On the reporting end, the data are now available and queryable in a variety of formats.

·         The EPA has begun to shorten the data release time through earlier “public data releases” on its website.[78]  (Much of the data has a reporting lag of a year or more.[79])

·         The releases and waste management activities of federal facilities were added in 1994; and seven new industries, including mining and electricity generation, were added in 1998.[80]

Weaknesses/Limitations of the TRI

·         Because the TRI does not mandate actual monitoring,[81] many facilities self-report releases using various estimation methodologies.[82], [83]  Not all of these can be double-checked through a review and adjustment process.[84] 

·         TRI data exclude many industry sectors and chemicals. According to the EPA’s National Toxics Inventory, non-point (i.e., mobile and area) sources may account for as much as 90% of all hazardous air pollutants.[85]  For areas like Pittsburgh, whose mobile sources include one of the highest volumes of riverboat traffic in the nation, this could mean an even greater lack of information.[86]

·         The data do not include all types of emissions, such as pollution released by the following major sources: air and ground transportation, dry cleaners and gas stations, sewage treatment plants, releases from landfills or abandoned and contaminated “brownfields” sites, pesticides, and hospitals.[87]  Also, the releases of smaller facilities with production below the reporting thresholds do not appear in the TRI.[88]  Although the impact of these polluters on individuals may be small, their emissions can add up: for example, Allegheny County has nearly 180 dry cleaning and laundry services.[89]

·         While not a weakness of the TRI itself, emissions standards for hazardous pollutants are based upon the best available technology for emissions control, not upon health risk.  When comparing TRI data to such standards, we must remember that meeting federal standards or permit allowances doesn’t necessarily equate to safety, especially for chemicals harmful in small amounts.[90]  

·         Companies are not required to report the amounts of toxic chemicals used in their processes or remaining in their products—they need report only emissions to air, water and land.[91]

·         The TRI does not include information on how the releases behave once they enter the environment, levels of human exposure, or chemical concentration within the food chain.[92]

·         The smallest geographic area for which aggregated data are available is the county.[93]  Very large facilities may mask the trends of smaller facilities in aggregated trend data.[94]

·         Facilities have the option of reporting a specific number of pounds released, or they may specify ranges of several hundred pounds.  The latter practice introduces a great deal of error in analyses.[95]

·         If the exact name of a facility’s owner company is unknown, a “facility ID number” may be required to locate the facility in the database.[96]

·         The TRI has also undergone a number of changes in reporting methodology over the years—many of these affect year-to-year comparisons and trend calculations.[97] 

TRI Data Tools

A number of recently developed data tools utilize TRI data:

·         TOXMAP,[98] a project of the U.S. National Library of Medicine, not only allows users to explore TRI data nationwide using a searchable map-based interface, but it also links to several databases of information on the specific health hazards of substances, such as the Hazardous Substances Databank (HSDB). 

·         Environmental Defense’s Scorecard tool[99] also provides information on health risks of chemicals, and allows searching based upon a preset list of plain-language questions, e.g., “What pollutants do the most harm?” or “Who’s polluting in my community?” 

·         The EPA Environmental Justice Geographic Assessment Tool[100] allows for mapping of air monitoring sites, Superfund sites and Toxic Release Inventory Sites in conjunction with select demographics such as population density and racial composition. 


Although they are still bound by the limitations of TRI data described above, these tools add great value through linkages to other datasets. 

Point Sources: Non-TRI

Continuous Emission Monitoring and Permit Data

While the TRI contains the vast majority of data related to point sources, additional limited data are available for people interested in a particular site.  Through several laws and programs, including the Acid Rain Program, a limited number of sites must conduct actual monitoring of specific chemicals in their emissions (e.g., through monitors placed in smokestacks), via Continuous Emission Monitoring Systems, or CEMSs.[101]  Chemicals so monitored include nitrogen oxides and sulfur dioxide.  A listing of Pennsylvania CEMS sites outside of Allegheny and Philadelphia counties, including the DEP region in which they fall (Pittsburgh is in Region 5) is available at the DEP website.[102]  Data for specific sites can be obtained from the Continuous Compliance Section of PADEP’s Bureau of Air Quality, Division of Compliance and Enforcement.[103]  For Allegheny County, contact ACHD’s Air Quality Program.[104]

Community public health advocates and researchers may wish to keep track of sites that have recently applied for emissions permits, and inspection results including violations of environmental regulations.  PADEP’s eFACTS (Environment Facility Application Compliance Tracking System) database includes an “eNotice” feature that allows for automatic e-mail updates regarding permit applications for specific counties, municipalities or programs (e.g., Air Quality, Safe Drinking Water). Users without the company or facility ID number can also search by name, or can produce a listing of facilities for a particular geographic area.[105] 

Allegheny County Emissions Report

As noted above, within Allegheny County, the Allegheny County Health Department collects emissions data from sites and reports it to the EPA.  In December 2004 ACHD’s Air Quality Program published an independent report including countywide emissions trend data for specific pollutants, emissions data for individual sites, and additional detail for Cheswick Station power plant.[106]  The report also includes estimates on the contribution of different sectors to particulate emissions, a topic discussed further under “Environmental Monitoring.”[107]  ACHD conducts a review and adjustment process for its emissions inventory of more than 120 sites within the county—this “double checking” process does not occur with the TRI.[108]   

National Emissions Inventory (NEI)

The National Emissions Inventory (NEI) also contains point source data for air releases.  These data can be obtained at the EPA’s Technology Transfer Network Clearinghouse for Inventories and Emissions Factors.[109]  Like the TRI, the NEI is based largely upon estimates.  While the federal government requires TRI reporting, states determine whether or not they wish to compile emissions inventories, and report them to the federal government.  Where NEI data are unavailable, the EPA’s Office of Air Quality Planning and Standards will make adjustments to TRI data for use in lieu of NEI data.  A major advantage of the NEI over the TRI is that the NEI includes separate emissions estimates for each known point of release at a facility, along with characteristics of the release point that are pertinent to emissions modeling (e.g., whether the point of release is at ground level, or from a 125-foot high stack).  The TRI will have one set of estimates just for the entire facility and will not differentiate between, for example, the emissions coming from each of two 200-foot high stacks, one 50-foot high stack, and two ground-level sources at the same facility.  This has important implications for determining possible human exposure, because pollution being released from a high stack will disperse to very different points than pollution being release at ground level.[110], [111] 

Case Study #2: Masontown and the Hatfield’s Ferry Power Plant


In February 2005, PennFuture: Citizens for Pennsylvania’s Future filed a lawsuit against Allegheny Energy for air pollution violations at their Hatfield’s Ferry Power Plant in Masontown, Greene County.  This plant, the second largest of 23 owned by Allegheny Energy, has caused complaints from local citizens regarding soot on their lawns and cars, and concerns about increased asthma incidences and higher-than-average cancer rates. These complaints continued despite the Pennsylvania Department of Environmental Protection (PADEP) fining the plant a total of $20,000 between 2000 and October 2004.  An Allegheny Energy spokesperson recently noted that the plant was in compliance with all state and federal regulations, admitting only the possibility of “minor technical violations…[that] were immediately reported and resolved.”[112], [113]  

In its complaint against Allegheny Energy,[114] PennFuture cited ten different counts, based upon several types of data:

·         Anecdotal evidence on the pollution’s effects upon a nearby citizen and her quality of life.  This included visible soot from the plant that forced her to clean frequently, stay indoors with her windows closed, purchase air cleaning equipment, keep her car in the garage, etc.  (Coincidentally, the woman’s husband had recently died from a rare form of cancer, but this fact was not outlined in the complaint.)

·         Point-source monitoring evidence that the plant had violated emissions guidelines outlined in state standards and in the plant’s permits.  This included two types of data:  1) continuous opacity monitoring of emissions from the plant’s boilers, done by permanent onsite equipment that plants meeting certain criteria are required to install[115] (a greater opacity basically means that the emissions are denser and contain a higher concentration of pollutants); and 2) a stack test for particulate matter (PM) emissions levels required by the plant’s operating permit under Title V of the Clean Air Act.


While the plant must collect opacity monitoring data continuously and report it to PADEP on a regular basis, they are required to conduct a stack monitoring test for PM emissions only once every five years.  Thus, they hired a firm to conduct this test only once in November 2002, which severely limited the monitoring data available.  Although these data weren’t available online, PennFuture obtained the data from PADEP relatively quickly after submitting a right-to-know request[116] in April 2004.[117] 

PennFuture is requesting that the court declare Allegheny Energy in violation of air emissions standards, order them to take whatever steps are necessary to comply, and order them to pay civil damages.  As of February, the U.S. Environmental Protection Agency and PADEP were “in discussion with Allegheny Energy regarding the compliance status of the plant.”  While it remains to be seen whether the case will be settled out of court, PADEP fined Allegheny Energy another $10,800 in November 2004, after PennFuture announced its intent to sue; and PADEP conducted a second stack test in March 2005.[118], [119] 

This example illustrates the following:

·         Point source monitoring data can provide additional strength to environmental health complaints, citizen observations and anecdotal evidence.

·         There may be serious limitations in monitoring data even for large sites—in this case, particulate matter emissions might vary drastically between five-year test intervals. 

·         Public data access laws may apply to data you seek, even if such data are not available online.[120]


Area Sources

Although this is not an exhaustive list, here we discuss data for several area sources that are particularly pertinent to environmental health.

Various Area and Mobile Sources: National Emissions Inventory (NEI)

 In addition to point sources as discussed above, county-level nationwide air emissions estimates for area sources and both road and non-road mobile sources are available through the EPA’s National Emissions Inventory (NEI) database.[121]  Estimates include 4 of the 6 criteria pollutants along with hazardous air pollutants (HAPs).  NEI data through 1999 can be accessed through the map-based, searchable AirData interface.[122]  We used AirData to generate the chart in Appendix F: Pittsburgh Region Carbon Monoxide Emissions.[123]

Animals: Concentrated Animal Feeding Operations (CAFOs)

CAFOs are feeding operations where large numbers of animals are housed in a very concentrated area, resulting in the production of large quantities of animal waste.[124]  Types of environmental releases from CAFOs that pose potential health risks include bacteria-laden waste and nitrates that can leach into groundwater and nearby streams and wells, as well as airborne manure particles that may cause illnesses.[125]  “All CAFOs are required to be self-monitoring” and PADEP “will inspect all large CAFOs at least once a year and spot-check smaller CAFOs.”[126]

Hazardous Waste Sites

A Superfund site is “any land in the United States that has been contaminated by hazardous waste and identified by the Environmental Protection Agency (EPA) as a candidate for cleanup because it poses a risk to human health and/or the environment.”[127]  The EPA’s Superfund site[128] has links to tools including the CERCLIS[129] database and Enviromapper, which allow searching for Superfund sites by various geographies.  CERCLIS includes the locations of 30 sites within Allegheny County, three of which are currently on the Superfund “National Priority List.”  On a related note, releases from petroleum storage tanks can contaminate water with MTBE (methyl tertiary-butyl ether), a chemical which makes gasoline burn cleaner and reduces air emissions, but may cause health problems if consumed via MTBE-contaminated water.  A 2003 USGS study includes a map of known releases from petroleum product storage tanks throughout Pennsylvania, for 1998-2001, and indicates which sites are near water supplies.[130] 

New Development Near Water

Although issues like runoff from parking lots and roads are considered in environmental assessments for new development, data on how new development and sprawl affect water quality do not yet appear to have been specifically collected in our region.[131]

Pesticide Applications

Since Rachel Carson Published Silent Spring in 1962,[132] we have become increasingly aware of the numerous health dangers of pesticides, which can pollute both the air we breathe and the water we drink.  The U.S. Geological Survey’s (USGS) Pesticide National Synthesis Project[133] includes nationwide estimates of regional patterns of annual pesticide use intensity of 208 compounds on 87 crops, but these data are based upon state-level estimates and are not intended for local-level estimates.  Additionally, the data were last compiled in 1997.[134]  Although Pennsylvania passed a law in 2002 requiring schools to be notified before pesticides are utilized nearby, the state is not required to compile data on use—thus the data are not housed in a centralized location.  The City of Pittsburgh has reported pesticide applications in an annual report by chemical, amount, and school since 1998.  The focus is on direct exposure to pesticides more than on indirect exposure (e.g., via water). [135],[136]  Ulster County, New York has an excellent example of a pesticide registry.[137] 

Sewer System Overflows

As is discussed in more depth elsewhere,[138] a major source of pollution for the Pittsburgh region’s rivers and streams is the combined stormwater and sanitary wastewater system that exists in older portions of the 83 combined municipal systems of the Alcosan water treatment service area.  Within this area are 317 overflow structures that release CSO (Combined Sewage Overflow) into rivers and streams when the system is overwhelmed by stormwater.  During wet weather periods, water levels of “indicator organisms” for waste matter, such as E. coli and fecal coliform, exceed federal thresholds—but, as described under environmental monitoring, the precise source is often not known.

The Three Rivers Wet Weather Demonstration Project maintains a GIS map database of more than 4,000 sewer lines through 83 communities, and plans to add information such as manhole locations and the size and current condition of sewer pipes.[139]  Additionally, the project maintains an online real-time rainfall data system for Allegheny County.[140]  However, we don’t yet know the total volume of water flowing out of each CSO structure (or the concentrations of potentially harmful materials and organisms) each time the system is overwhelmed.  Additionally, we don’t know the extent or locations of cracks in aging sewer pipes, or of illegal stormwater hookups, which increase the stormwater flowing into the system and thus the outflow at CSO structures.

Mobile Sources

The EPA has estimated that as much as half of all cancers due to outdoor air toxics may be due to mobile sources.[141]  This includes road vehicles such as cars and trucks,[142] but can also include non-road sources like ships, trains, and powered lawn equipment.  Depending upon the vehicle or equipment type, pollutants may include carbon dioxide, carbon monoxide, nitrogen oxides, hydrocarbons, and diesel particulate matter (PM).[143]  While county-level estimates of mobile sources are also available through the National Emissions Inventory[144] described above, we list more detailed data sources and studies here.  Note that some of these data are also based upon source release modeling, as opposed to actual monitoring.

Mobile Hazardous Waste Accidents

In February 2005, a derailed train car with 15,000 to 20,000 gallons of anhydrous hydrogen fluoride plunged into the Allegheny River.[145]  Because great volumes of potentially hazardous chemicals are shipped through our region each year, it is important to know what is released from mobile sources via accidents—either major or minor—and where.  The U.S. Department of Transportation’s Hazardous Materials Incident Database[146] has downloadable tables for 1993-2004 including incident time and location, mode of transportation, and reported amounts and types of substances released.

On-Road Vehicle Emissions

The Clean Air Task Force’s map-based “Diesel and Health in America” tool includes estimates of diesel pollutants emitted by both on-road vehicles and non-road heavy equipment, along with the health risks associated with those pollutants.  Estimates are available at the national, state, metropolitan area and county level.  This tool can be accessed through the Group Against Smog and Pollution’s (GASP) website, and is also queryable by ZIP code.[147]  Environmental Defense’s “Tailpipe Tally” estimates emissions for specific makes and models of cars.[148]  For transportation planning purposes, the Southwestern Pennsylvania Commission (SPC) used its transportation model to generate several scenarios, including 2002-2030 volatile organic compound (VOC) and nitrogen oxide (NOx) emissions estimates and planning projections in kilograms per day for several areas throughout the Pittsburgh region.[149]  These data, however, may be more suited for a specific planning purpose than for general use.  Carnegie Mellon University’s Air Quality Group wishes to conduct additional air monitoring near mobile sources in the Pittsburgh area, e.g., in tunnels, near the parkway, or in a downtown “street canyon.”  Among other goals, this group hopes to further address questions surrounding the contribution of mobile sources to overall air pollution.[150]    

Ship Emissions

Because Pittsburgh is the second busiest inland port in the U.S.,[151] area ship engine emissions may contribute as much nitrogen dioxide to region as a major highway.[152]  James Corbett, a former Carnegie Mellon University student, measured the particulate matter and sulfur dioxide emissions of various types of ships worldwide, establishing one of the world’s first ship emissions inventories.[153]  Some of his work can be accessed through his University of Delaware faculty page.[154]