Member Login                                                                              About Us · Contact Us · Glossary · Site Map · Translator
STAPPA

Air Pollutants : NACAA Positions| Related Documents| Related Links

There are many types of air pollutants. The exact composition and concentration of pollutants depend on the source activity or process, the type of fuel and/or chemicals involved, and in some cases the meteorological conditions under which the pollutant is emitted. Air pollutants are responsible for a range of adverse health and environmental effects. “Criteria” air pollutants are those pollutants for which air quality criteria (e.g., ambient air quality standards) have been established under the Clean Air Act; the six criteria air pollutants are carbon monoxide (CO), nitrogen oxides (NOx), particulate matter (PM), sulfur dioxide (SO2), lead and ozone.. Other air pollutants include ammonia and volatile organic compounds (VOCs). In addition, combustion of fossil fuels, along with a limited number of other sources such as animal feedlots, produce greenhouse gases such as carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4). These gases have been implicated in global warming effects. In addition, there are 188 toxic or “hazardous” air pollutants (HAPs). These pollutants can have more serious health impacts than the general criteria pollutants, depending on the level of exposure. In many cases, toxic pollutants constitute a small fraction of the total hydrocarbon or PM emissions.
Reductions in air pollution can be achieved by a variety of methods including pollution prevention, control technologies, and control measures and may be implemented through regulatory, market-based or voluntary programs. A control strategy may include a combination of different voluntary measures or mandatory controls, may focus on one or several pollutants or sources of air pollution, and can be implemented on a local, regional, national, or international scale. Energy efficiency and renewable energy are examples of pollution prevention strategies. Almost all air quality improvements to date have been achieved through technological developments. Air pollution control technologies have achieved stunning results in reducing emissions from the manufacturing and mobile source sectors by as much as 90 to 99 percent. Continuing advances in both pollution prevention and air pollution control technology should enable further emissions reductions to offset increased emissions caused by continued population growth and worldwide economic development.

NACAA Positions

Related Documents

Related Links


Subtopics


Haze :  NACAA Positions| Related Documents| Related Links

Haze, or visibility degradation, is caused when sunlight encounters tiny particles in the air. Some of the light is absorbed by particles while other light is scattered. This absorption and scattering of light reduces color and clarity of what we see. Sulfate particles scatter more light than other particles, especially during humid conditions. A particular concern is the reduction of visibility in the national parks and wilderness (i.e., Class I areas). Haze pollutants can include natural sources such as windblown dust and wildfires, as well as manmade sources such as motor vehicles, electric utilities, other industrial operations, and forest and agricultural burning. Regional haze control strategies focus on reductions of fine particles and their precursors, such as ammonia. Because fine particles can transport over long distances, sources located far from a Class I area can be a concern. EPA recently promulgated the final regional haze rule (RHR), which requires states to establish and develop long-term control strategies to meet “reasonable progress” goals, including an analysis of sources subject to “best available retrofit technology” (BART) requirements. States must submit RHR State Implementation Plans by December 17, 2007.

NACAA Positions

Related Documents

Related Links


Mercury and Other Toxic Air Pollutants :  NACAA Positions| Related Documents| Related Links

Toxic air pollutants are substances that cause or may cause cancer or other serious health effects, such as reproductive or birth defects, and neurological, cardiovascular, and respiratory disease. They can be found in gaseous, aerosol, or particulate forms. Some toxic air pollutants, such as mercury (Hg), are persistent bioaccumulative toxics (i.e., they are stored indefinitely in the body and increase over time). These toxics can deposit onto soils or surface waters, where they are taken up by plants and are ingested by animals, with concentrations increasing as the toxics move up through the food chain to humans. Sources of hazardous air pollutants include stationary sources such as powerplants, factories, dry cleaners, and hospitals, as well as mobile sources such as cars, buses, and construction equipment.
Control of mercury emissions is based upon reduction of the emissions and pollutant releases into the atmosphere by the industries that use mercury within their processes, emit mercury or dispose of products containing mercury, such as thermometers. In the U.S., national emission standards for hazardous air pollutants (NESHAPS) have been established for industries emitting toxic air emissions that require the use of Maximum Achievable Control Technology (MACT) for compliance. For example, mercury NESHAP/MACT standards have been promulgated for hazardous and municipal waste incineration, commercial/industrial boilers, chlor-alkali plants, and portland cement kilns. Strategies for controlling mercury and other toxic air pollutants include pollution prevention measures, including product substitution, process modification, work-practice standards and materials separation; coal cleaning (relevant to mercury control); flue gas treatment technologies; and alternative strategies. Significant sources of toxic air pollution are motor vehicles, so programs to reduce emissions from cars, trucks and buses also decrease concentrations of toxic air pollutants. These programs include reformulated gasoline, the national low emission vehicle (NLEV) program, and gasoline sulfur control requirements among others.

NACAA Positions

Related Documents

Related Links

  • Go to related links for more information about Mercury and Other Toxic Air Pollutants


Ozone :  NACAA Positions| Related Documents| Related Links

Ozone (O3) is created by a chemical reaction between NOx and VOCs that is generated by heat and sunlight. A large share of ozone-generating pollutants is produced by motor vehicles, although any fuel combustion source emits the pollutants that can contribute to ozone formation. Ozone is a major problem in many urban areas around the world where it can reduce lung capacity and increase susceptibility to respiratory illnesses, especially in children and the elderly. Control strategies may comprise a set of regulations that specify emission limits and/or control equipment that are deemed to be reasonable available control technology (RACT), best available control technology (BACT), or lowest achievable emission rates (LAER), depending on the severity of the nonattainment problem in the area. NOx and VOC control equipment or programs may address specific industrial processes, or focus on on-road vehicles, nonroad equipment such as locomotives, and nonpoint sources such as small industrial boilers, dry cleaners, and consumer solvents. Pollution prevention measures such as use of non- or low-VOC content solvents and coatings can also be part of an effective ozone control strategy. On April 15, 2004, EPA designated 432 counties and 42 partial counties as nonattainment areas for the 8-hour ozone standard, and these areas face deadlines between 2007 and 2024 (depending on the severity of their ozone problem) for attaining that standard. On March 15, 2005, EPA announced the Clean Air Interstate Rule (CAIR), which addresses ozone transport across the boundaries of 25 states and the District of Columbia. CAIR contains reduction targets for NOx during the summer that can be met through a cap-and-trade system for electric utilities. Early Action Compacts allow areas that are close to attainment of the new 8-hour ozone standard to submit actions plans demonstrating they will meet the standard earlier than required and defer the impact of a nonattainment designation.

NACAA Positions

Related Documents

Related Links


Particle Pollution :  NACAA Positions| Related Documents| Related Links

Particulate matter can be either emitted directly by sources (primary) or formed in the atmosphere from precursors (secondary). Primary particles are generated by combustion such as the burning of diesel fuel, and by mechanical generation such as the churning of road dust, brake wear, and construction activities. Secondary particles form in the air due to complex chemical reactions that convert gaseous precursor pollutants (NOx, SOx, VOC, and ammonia) into particles. Most dangerous are the fine particles (PM2.5) which can be absorbed deep in the lungs, causing aggravated asthma, decreased lung function, lung cancer, cardiac problems, and premature death. Control strategies could include a set of regulations that specifies emission limits in either mass or opacity units. PM control equipment or programs may address specific industrial processes, or focus on nonroad equipment such as locomotives, other equipment that burns diesel fuel, and nonpoint sources such as dust from agricultural activities and travel on paved and unpaved roads, and smoke from fireplaces and woodstoves. EPA designated 208 counties areas as 39 nonattainment areas for the fine particle standard, and these areas face a deadline of 2010 for attaining that standard. On March 15, 2005, EPA announced the Clean Air Interstate Rule (CAIR), which addresses transport of the PM2.5 precursors NOx and SOx across the boundaries of 28 states and the District of Columbia. CAIR contains reduction targets for NOx and SOx that can be met through a cap-and-trade system for electric utilities.

NACAA Positions

Related Documents

Related Links