Frequently Asked Questions about Air Toxics 

Air toxics are generally defined as air pollutants known or suspected to cause cancer or other serious health problems. They also may disrupt reproductive processes, cause birth defects and can cause serious environmental and ecological problems. Studies indicate that Oregonians are being exposed to a number of air toxics at potentially harmful levels.

Air toxics come from a variety of sources including cars and trucks, all types of burning (including fireplaces and woodstoves), businesses, and consumer products such as paints.

EPA studies show Portland, like many other urban areas, has a greater health risk from air toxics than less densely populated areas. Portland's air is comparable to other cities with similar populations. The 2008 U.S. Census estimates that Multnomah County is the 80th most populated county out of 3,140 counties in the country. This means Multnomah County is within the top 2.5 percent of counties based on population.

In June 2009, EPA released the latest version of the National-Scale Air Toxics Assessment (using 2002 data). This modeling study identifies and prioritizes air toxics, emission source types and locations that are the greatest potential concern for health risk.

DEQ used this information and its own modeling studies to identify the air toxics of most concern in Oregon. Portland has the highest levels of air toxics in the state primarily because Portland is the most populous city in Oregon. DEQ and EPA agree on the estimates of air toxics levels. In the Portland area, the air toxics of most concern are benzene, toxic combustion by-products (known as polycyclic aromatic hydrocarbons), and soot from diesel engines.

DEQ is working with an advisory group in the Portland region to reduce air toxics through the Portland Air Toxics Solutions project.

Studies indicate that air toxics are produced by large industry and a variety of small sources. These sources include cars and trucks, construction machinery, printers, auto repair and auto body shops, metal fabricators and many other small businesses that use paints or chemical cleaners.

Although each of these activities may only release a small amount of toxic air pollution, the combined effect can be significant. Many cities show air toxics coming primarily from these kinds of activities. Even the use of household chemicals play an important part in raising the concentrations of air toxics, both indoors and outdoors. More information...

According to various studies, high concentrations of air toxics exist in most counties in Oregon. The highest concentrations of air toxics are in Multnomah, Washington and Clackamas counties, where population and vehicle use are highest and where there is the most industrial and business activity. However, air toxics at levels of concern can be found anywhere in the state where there are motor vehicles, fuel burning, small businesses using chemicals and larger industrial activities.

Both federal and state officials are working to reduce air toxics releases. Since 1990, EPA has been working on a more effective approach to reducing toxic air pollutants. New regulations on large and small manufacturers resulted in considerable reductions of air toxics coming from many types of industrial processes. DEQ adopted regulations identical to EPA’s and inspects facilities to make sure that these regulations are followed. Additional regulations on cars, trucks, and other mobile air pollution sources will go into effect over the next few years.

In 2003, DEQ formed a state air toxics program that uses the best available science to identify and solve air toxics problems statewide. An Air Toxics Science Advisory Committee has helped DEQ develop its own health-based benchmarks.

Though more is needed to address air toxics, DEQ has several long-standing programs that have sought to reduce air pollution and have also contributed to reductions in toxic air pollutants. These include:

• Vehicle inspection programs in Portland and Medford areas
• Permitting of industrial sources
• Providing assistance to small businesses to adopt Best Management Practices
• Public outreach and education efforts
• Air Pollution Advisories

• Because motor vehicles emit the most air toxics, we can all help by driving less (reducing trips, using public transportation, carpooling and telecommuting).
• As consumers, we can choose products that emit fewer volatile organic compounds, which are usually air toxics as well. Many paints and other products are now available in low toxicity formulations.
• Other ways of reducing air toxics include reducing woodstove use, tuning up vehicles, and using cleaner burning small engines.

Yes, some air toxics can cause reduced visibility called haze. Air toxics that may cause haze in the Portland area include any pollutant that is or can be transformed into a tiny particle.

See DEQ's Regional Haze page for more information about haze and visibility.

The 2005 National Air Toxics Assessment study estimates there could be up to 161 additional cancers over a lifetime for the 1.5 million people living in the Portland region. This means there could be 87 extra cancers in Multnomah County, 32 in Clackamas County and 42 in Washington County. The study assumes everyone is equally and continuously exposed to air toxics for 70 years.

DEQ routinely measures: arsenic, beryllium, cadmium, chromium, cobalt, lead, manganese, nickel, selenium and hexavalent chromium, also volatile organic compounds, aldehydes and ketones.

The DEQ Air Quality Annual Report has summaries of some of the air toxics monitoring results. For the complete data record, go to the DEQ LASAR database. These files are also available on the EPA website.

At the air toxics monitoring site in Portland, DEQ uses sampling, analysis system and standard operating procedures the U.S. EPA established. DEQ monitors collect PM₁₀ (particulate less than 10 microns in size) samples over 24 hours, every sixth day, on a filter that the DEQ laboratory analyzes for metals using inductively coupled plasma with mass spectrometry. In addition, DEQ collects gas samples in stainless steel canisters. DEQ laboratory staff analyze these samples using gas chromatography with mass spectrometry. DEQ collects other gas samples in absorber tubes and analyzes them colorimetrically.

In 1999, 2000, and 2005, DEQ monitored air toxics including airborne metals at six residential locations in the Portland region: North Portland, Southeast Portland, Southwest Portland, Northwest Portland, Beaverton, and Vancouver. DEQ did additional monitoring in Northwest Portland between 2000 and 2005.

• Annual average concentrations of arsenic varied across the six sites from a low of 0.93 to a high of 1.74 nanograms per cubic meter of air. The benchmark for arsenic is 0.2 nanograms per cubic meter of air. This indicates the entire region is above the health benchmark.
• Annual average concentrations of cadmium varied across the six sites from a low of 0.38 nanograms per cubic meter of air at the Beaverton site to a high of 2.57 nanograms per cubic meter of air at the North Portland site. The benchmark for cadmium is 0.6 nanograms per cubic meter of air. Measurements of cadmium are above and below the benchmark.
• Annual average concentrations of lead varied across the six sites from a low of 3.18 nanograms per cubic meter of air to a high of 11.7 nanograms per cubic meter of air. The benchmark for lead is 150 nanograms per cubic meter of air. Measurements at all of the sites were below the benchmark.
• Annual average concentrations of manganese varied across the six sites from a low of 3.8 to a high of 41.9 nanograms per cubic meter of air. The current benchmark for manganese is 200 nanograms per cubic meter of air. The new proposed benchmark is 90 nanograms per cubic meter of air. All of the sites were below both the current and proposed benchmarks.
• Hexavalent Chromium was seldom measured above the minimum detection limit of 0.04 nanograms per cubic meter of air in the 2005 Portland area study. Only the Northwest Portland site had an annual average concentration above the minimum detection limit, based on 49 valid daily samples collected over the year. It was 0.045 nanograms per cubic meter of air, below the ambient benchmark for hexavalent chromium which is 0.08 nanograms per cubic meter of air.
• DEQ measured antimony as part of a special particulate matter study. A majority of the measurements are below the detection limit but DEQ has some data above the detection limits from both Southeast Lafayette and North Portland. The maximum value measured is 0.0768 for antimony. There is no benchmark for antimony because EPA does not list it as a hazardous air pollutant and DEQ has not measured high concentrations of this pollutant.
• DEQ measured mercury as part of a special particulate matter study. A majority of the measurements are below the detection limit, but DEQ has some data above the detection limits from both Southeast Lafayette and North Portland. The maximum value measured is 0.00454 micrograms per cubic meter for mercury. The current benchmark for mercury is 0.3 micrograms per cubic meter and the proposed benchmark is 0.03 micrograms per cubic meter. DEQ never has measured mercury above the current or proposed benchmarks.

Yes, DEQ's air toxics program will focus efforts on reducing the important sources of air toxics.

Oregonians need more information about air toxics and how air pollution may be affecting us. Until recently, the only available forum for Oregonians to voice concerns has been through DEQ's industrial source permitting process. That process focuses attention on large industrial point sources but does not provide an opportunity for DEQ to discuss the effects of other significant pollution sources. A variety of studies show the importance of reducing non-industrial sources of air toxics to improving human health.

DEQ's air toxics program provides Oregonians with vital information about the air we breathe. More importantly, it identifies the factors that affect the quality of that air and our own individual roles in protecting it. This approach will give Oregonians the tools needed to decide how to protect our community's air, our health and the health of our families, friends and neighbors.

DEQ's air toxics monitors collect samples over a 24-hour period. DEQ's laboratory staff analyze these samples to determine daily concentrations of a variety of air toxics. The daily samples are used to determine annual average concentrations. While DEQ can conduct special monitoring studies to determine hourly or shorter concentrations, the shortest time period for which air toxics concentrations can be determined from routine air toxics monitoring is 24 hours.

In 2005, DEQ participated in a study that tested a new tool to collect data for a period shorter than 24 hours. This 15-minute data compares well to DEQ's 24-hour data. DEQ frequently participates in this type of study to evaluate new technology.

Yes, DEQ analyzes both long-term and short term concentrations.

For air toxics with the highest levels in Oregon, the most significant health problems come from long-term exposure. Long-term exposure to low concentrations of air toxics can cause cancer and other health problems. The Oregon Environmental Quality Commission (EQC) established health-based benchmark concentrations for air toxics in Oregon to protect sensitive individuals over a lifetime (70 years) of exposure.

Short term exposure to higher levels of air toxics can cause short-term health problems as well. At present, the EQC has not established short-term benchmarks, but DEQ can compare short-term concentrations to other agencies' benchmarks. For example, EPA established 24 hour sample screening levels as part of its national school air toxics monitoring project.

DEQ looks at daily average concentrations as part of the quality assurance process. DEQ reviews any daily concentration that is above the historical high concentration for a pollutant to ensure that it did not result from a quality control problem, such as contamination of a sample. Legitimate high daily concentrations can be caused by stagnant weather conditions or unusual emission activities, even if those events last less than 24 hours. For example, concentrations of toxic metals often spike on July 4th because of fireworks use.

DEQ will evaluate the need to formally adopt short–term benchmarks for Oregon. At present the focus of DEQ's air toxics program is to reduce significant risks of cancer and other chronic diseases caused by long-term exposure to air toxics. The emission reduction measures adopted to reduce long-term exposures in many cases also reduce the potential for short-term emission spikes that could lead to acute health problems.

The Toxics Release Inventory is an EPA database that includes the following information about the release of industrial chemicals into the environment:

• Locations and quantities of chemicals stored on-site in order to help communities prepare to respond to chemical spills and similar emergencies
• Annual data on releases and transfers of certain toxic chemicals from industrial facilities
• Waste management data and pollution reduction activities

The primary purpose of the Toxics Release Inventory is to inform communities and citizens of chemical hazards in their areas. EPA requires companies to report releases of certain toxic substances to the air, water and land to the Toxics Release Inventory.

The goal of the community right-to-know laws is to empower citizens, through information, to hold companies and local governments accountable in terms of how toxic chemicals are managed. The data often spurs companies to focus on their chemical management practices since these practices are being measured and made public. In addition, the data serves as a rough indicator of environmental progress over time. Companies self-report and EPA requires them to use the best information they have readily available. EPA ensures that businesses report and does a cursory review of the data, but does not verify the accuracy of the reports.

EPA requires DEQ and other states to conduct statewide inventories of all air pollution sources every three years to create a national emissions inventory. This inventory includes emissions from all sources of air pollution including large and small industries, commercial operations, residential activities, transportation, burning, and construction activities. EPA uses the emission inventory to track emissions on a national scale, develop new rules, and conduct computer modeling of air pollution.

DEQ compiles detailed area-specific emissions inventories when a region does not meet a National Ambient Air Quality Standard. DEQ uses this inventory to work with local government and industry representatives and community members to produce emissions reduction strategies. DEQ uses the information contained in the inventories in computer modeling exercises to ensure that the strategies will be able to meet the air quality standard over the 10-year life of the plan. DEQ is compiling an area-specific and pollutant-specific inventory for the Portland Air Toxics Solutions project. Other examples include an inventory of pollutants that reduce visibility at national scenic areas, a Klamath Falls fine particulate inventory, and an inventory of greenhouse gases that contribute to climate change.

The purpose of each inventory is different and they include different information. The agencies require different levels of checks and balances. The Toxics Release Inventory applies to industrial facilities and not other sources of air pollution. The DEQ inventory follows national protocols for calculating emissions from all types of air pollution sources and is quality checked internally.

EPA requires companies to report more chemicals for the Toxics Release Inventory than DEQ does under its Air Quality Permit program.

Companies with air quality permits must report hazardous air pollutants, which is a group of air toxics designated by EPA under the Clean Air Act. The current list of hazardous air pollutants includes 187 entries, of which most are individual chemicals along with several groups of chemicals.

The Toxics Release Inventory is an element of the federal Emergency Planning and Community-Right-to-know Act. The list of chemicals that facilities must report to EPA for the Toxics Release Inventory includes 581 individual chemicals plus 30 groups of chemicals that facilities store or emit. Companies must report releases of these chemicals to the air, water, land, and underground injection control systems, as well as transfers of these chemicals to waste disposal sites. Because the list includes more chemicals than are included in the hazardous air pollutants list, a company's Toxics Release Inventory report may list more chemicals than it reports under its air quality permit.

Another difference between the Toxics Release Inventory and hazardous air pollutants lists has to do with definitions for some chemicals. For example, glycol ethers are on both the Toxics Release Inventory and hazardous air pollutants list, but the definition of glycol ethers on the hazardous air pollutants list differs from the definition on the Toxics Release Inventory list. While facilities must report one specific glycol ether (ethylene glycol monobutyl ether) for the Toxics Release Inventory, this pollutant does not appear on the hazardous air pollutants list, and is therefore not covered by the Clean Air Act or a permit.

DEQ emissions inventory data is included in the EPA national emission inventory database. Because this information is available on the EPA Website, DEQ decided to conserve limited resources by not creating a duplicate searchable system.

The federal Agency for Toxic Substances and Disease Registry has fact sheets on most air toxics. Here are links to the air toxics in Portland for which DEQ has benchmarks.

• Acetaldehyde (EPA)
• Acrolein
• Arsenic
• Benzene
• 1,3 Butadiene
• Cadmium
• Chromium VI
• Diesel Particulate Matter (EPA)
• Ethylbenzene
• Formaldehyde
• Lead
• Manganese
• Methylene Chloride
• Naphthalene
• Nickel
• Para dichlorobenzene
• Polycyclic Aromatic Hydrocarbons (PAHs)
• Tetrachloroethylene (Perc)
• Trichloroethylene (TCE)

Ambient benchmark concentrations are reference values with which air toxics problems can be identified, evaluated, and addressed. The Oregon Environmental Quality Commission (EQC) adopted ambient benchmark concentrations for 51 air toxics of concern in Oregon based on recommendations from DEQ and DEQ's Air Toxics Science Advisory Committee.

The benchmark concentrations are based on levels that protect the health of our most sensitive individuals. These benchmarks provide consistent health-based goals designed to focus pollution reduction efforts. Benchmarks are expressed as micrograms or nanograms of a specific toxic per cubic meter of air. In practice, ambient concentrations of each air toxic will be determined through monitoring or through use of an air quality model for comparison to the benchmark concentrations.

Oregon's benchmarks are meant to reflect levels that would result in a cancer risk of one in a million based on a lifetime of exposure or, for non-carcinogens, levels you could breathe for a lifetime without any non-cancer health effects. For pollutants that cause health effects other than cancer, the benchmarks reflect levels that cause adverse effects, such as respiratory irritation, reproductive or nervous system damage.

At present, the benchmarks are set to prevent chronic diseases from long-term exposure to breathing air toxics.

Based on the current best available science, the answer is yes. A benchmark is designed to protect people, including sensitive individuals, from non-cancer health effects or from a more than one in a million chance of cancer during a lifetime of exposure. A benchmark is intentionally set far below the point where a response is expected. This allows a wide margin of safety in response to ever present scientific uncertainty. Exceeding a benchmark by a small amount does not mean an adverse health effect is certain or even likely. It means that DEQ needs to do further investigation.

• More on benchmarks

This is one of the most complex issues in contemporary toxicology. Science does not yet have a way of providing a precise answer given the potential infinite number of possible chemical mixtures in the environment. To get at this question in a reasonable, practical way, EPA recommends assuming that doses and responses to pollutants are additive. When assessing risk from air pollution, DEQ typically takes a precautionary approach assuming that interactions may exist when none may exist and that every person is exposed to all chemicals all the time for a lifetime.

The effects of lead are the same whether it enters the body through breathing or swallowing. The main target for lead toxicity is the nervous system, both in adults and children. Children are more sensitive to the health effects of lead than adults. Exposure to lead in the womb, in infancy, or in early childhood may slow mental development and cause lower intelligence later in childhood. It appears that some of these effects, particularly changes in the levels of certain blood enzymes and in aspects of children's neurobehavioral development, may occur at blood lead levels near zero. Therefore there may be no safe level.

After lead was removed from gasoline many years ago, lead levels in Oregon's air dropped dramatically. Oregon has been in compliance with the federal lead standard since 1976. Based on DEQ's past monitoring, all areas in Oregon are below the recently tightened federal lead standard. Part of the new lead standard requires new monitoring near industries reporting over a ton of lead emitted per year and in metropolitan areas with population greater than 500,000. Under these criteria, EPA requires lead monitoring at Cascade Steel in McMinnville and in the City of Portland.