Module 4.1 Pollution Prevention

Transcription

1 Module 4.1 Pollution Prevention Prevention of Air Pollution from Point Sources Prevention of Air Pollution from Point Sources Reducing pollution to air involves considering Point sources Nonpoint sources Stationary Mobile Module 4.1 will consider point sources of pollution Module 4.2 will consider nonpoint sources of pollution Air Pollution Air pollution concerns: Global climate change Stratospheric ozone depletion Increased UV rays and more skin cancers Acid deposition Effects on forests, buildings, lakes, etc. Urban smog and particulates Direct health effects Especially on people with breathing problems like asthma, emphysema, cancer, etc. Air Pollution Primary pollutants are those actually emitted Some undergo chemical reactions to form secondary pollutants Sulfur dioxide (can become sulfuric acid creating acid deposition) Nitrogen oxides (can become nitric acid and create acid deposition, climate change, smog) Volatile organic compounds (smog) Carbon monoxide (direct effect) Carbon dioxide (climate change) Methane (climate change) Chlorofluorocarbons (ozone layer depletion, climate change) Particulates from dust and smoke (direct health effects) 1

2 Point and Nonpoint Sources Regulation of Point Sources A point source is a location with an identifiable point of discharge to the air Point sources include: Industrial facilities Power plants Nonpoint sources are without an identifiable point of discharge Nonpoint sources include: Internal combustion engines Airborne dust and dirt Smoke Discharge of pollutants to air is regulated under: The Clean Air Act (CWA) of 1970 Amended in 1977 and again in 1990 The CAA includes the National Ambient Air Quality Standards (NAAQS) for six criteria pollutants National Emissions Standards for Hazardous Air Pollutants (NESHAPS) Regulation of Point Sources National Ambient Air Quality for six criteria pollutants Carbon monoxide Sulfur dioxide Nitrogen oxides Ozone Lead Particulate Matter at 10 and 2.5 microns in size National Ambient Air Quality EPA calls six pollutants criteria air pollutants because the agency regulated them by developing health-based and/or environmentallybased criteria as the basis for the permissible levels. One set of limits (primary standard) protects health; another set of limits (secondary standard) is intended to prevent environmental and property damage. A geographic area that meets or does better than the primary standard is called an attainment area. Areas that don't meet the primary standard are called nonattainment areas. 2

3 National Ambient Air Quality EPA classifies the nonattainment areas according to how badly polluted the areas are. Five classes of nonattainment areas for smog ranging from marginal to extreme Two for carbon monoxide and particulates Clean-up requirements and deadlines are set for nonattainment areas National Ambient Air Quality States with nonattainment areas must show EPA that they are making reasonable progress States use the permit system to make sure power plants, factories and other pollution sources meet their clean-up goals. The CAA uses a technology based control strategy NAAQS nonattainment areas require the implementation of Best Available Control Technologies (BACT) National Emissions Standards for Hazardous Air Pollutants (NESHAPS) EPA refers to chemicals that cause serious health and environmental hazards as hazardous air pollutants or air toxics. List of 188 toxic air pollutants that the EPA tracks under National Emission Standards for Hazardous Air Pollutants (NESHAPS) Requires the implementation of Maximum Achievable Control Technology (MACT) CAA Permit Program The 1990 Clean Air Act set up a permit program for large point sources Under the new program, permits are issued by states or the EPA. The permit includes information on which pollutants are being released how much may be released steps to be taken to reduce pollution, including plans to monitor (measure) the pollution. 3

4 CAA Permit Program The permit system is especially useful for businesses covered by more than one part of the law, since information about all of a source's air pollution are included For instance, an electric power plant may be covered by the acid rain, hazardous air pollutant and non-attainment (smog) parts of the Clean Air Act; the detailed information required by all these separate sections will be on the permit. The Pollution Prevention Hierarchy As always, the pollution prevention hierarchy gives a rank ordered list of activities from most desirable to least: Reduce at the source Reuse whenever possible Recycle Treat Dispose Reduce Air Emissions at the Source Examples of source reduction activities in industry include: Change the process so as not to create an air emission stream Reduce combustion since burning material results in air emissions Close the system from flow-through to closed loop Change to a cleaner type of fuel for combustion From high sulfur coal to low sulfur coal From coal to oil to natural gas Reduce use of CFCs Reuse/Recycling of Air Air is not a scarce resources so this is not nearly as common as for water Some processes may allow for cleanup and reuse of a stream of air Heating/cooling for example 4

5 Treatment of Air Emissions Treatment of air emission streams is common and includes installation of Scrubbers Precipitators Filters Chemical, physical, and even biological treatment Typically these treatments capture pollutants from the air medium and transfer it to a solid waste stream Disposal of Air Once the emission stream has been properly treated, disposal to the air is easy and safe The key to this is proper treatment and monitoring to ensure that what is being emitted is clean enough to meet standards Implementing P2 for Air To implement a program: Research the pollutant loads Permits should specify contaminants and maximum levels allowed Test records should characterize actual contaminants and levels (often well below permit levels) Tie the contaminants and quantities to the various sources Research information on your industry/process Implementing P2 for Air Stay as high on the hierarchy as possible Identify opportunities Involve everyone affected Calculate economic payback periods Publicize success Keep good records 5