AIR

The Clean Air Act and Controlling Air Pollution

History of Legislation

• Original CAA of 1955 predates the EPA by 15 years

• It authorized technical and financial assistance to states

• Amendments were made in the 60’s, in 1970, 1977, and most recently in 1990

1960’s Amendments

• Amendments in the 60’s granted federal authority over vehicle emissions

• In 1970 requirements for national standards of ambient air quality were established NAAQS – w/ separate standards for new cars & stationary sources

1970 Amendments

• In 1970 air toxics were added as a new category of pollutants not covered under the original standards

• The National Emissions Standards for Hazardous Air Pollutants or NESHAP

• Substances included arsenic, asbestos, benzene, beryllium, mercury, radionuclides, radon 222, and vinyl chloride

State Requirements – 1970, Title I

• States were required to draw up state implementation plans – SIPs

• SIPs or State Implementation Plans are a collection of regulations a state will put into place to achieve the goals of the CAA

• These detail how ambient air standards would be met in each “air quality control region”

• The plan must include an inventory of all present sources and operating standards for all new development

• The EPA oversees the individual states’ plans and will take over enforcement if the state’s plan is unacceptable

1977 & 1990 Amendments

• The 1977 amendment stated that new facilities could be built in an area that was not meeting standards if existing sources could reduce their pollution

• The original act was just 50 pages long

• The 1990 amendments are close to 800 pages!

• The 1990 amendments addressed new issues such as acid rain emissions and moves to preserve the stratospheric ozone layer

• It established a system of tradable emission credits

Criteria Air Pollutants

• Primary standards – maximum ambient concentrations for the protection of the public health

• Secondary standards – levels acceptable to protect the public welfare

Nonattainment

• Not meeting the EPA’s primary standards

• 90 million Americans, 35% of the population live in nonattainment areas (mostly in urban areas)

Levels of Nonattainment

• Range from marginal to extreme

• Set for each of the criteria air pollutants

• The EPA tailors cleanup plans to the severity of the problem and sets goals that must be met or even stricter requirements will be enforced

Offsets

• When a company wants to expand

• The effect of new pollution sources must be offset by reductions elsewhere within the company or somewhere in the nonattainment area

Title IIMobile Sources

• Cars produce 60-80% less pollution than they did in the 1960’s

• However, automobiles still release over half of the smog-forming VOC’s and nitrogen oxides

• Motor vehicles emit 90% of the CO found in urban air

More Cars on the Road

• In 1970 Americans traveled 1 trillion miles

• Today we drive 4 trillion miles a year

• Public transportation and car pooling have not been embraced by the general population

• Removing lead from gasoline actually increased the amount of VOC’s released

• Pollution control devices, added to cars in 1970, were only designed to function for 50,000 miles

New Solutions in 1990

• Cleaner fuels

• Auto inspection requirements

• Removing sulfur from diesel fuel

• Reformulated fuels with less VOC’s such as benzene

• Oxygenated fuels in cold areas to aid in more complete combustion

• Detergents in gasoline prevents build-up of engine deposits which hamper efficient operation

• Development of alternative fuel sources such as alcohol, liquefied petroleum gas and natural gas

• Vapor recovery nozzles at gas stations

Title IIIAir toxics or hazardous pollutants• Benzene is released by motor vehicles

• Area emitter - Many small stationary sources include gas stations, paint shops and dry cleaners

• Major emitter - Chemical factories and coal-burning power plants are considered large stationary sources

Title IVAcid Rain

• Coal burning power plants in the Midwest and the Northeast are the primary source

• Coal from these regions has a much higher sulfur content

• Under Title IV, plants must have continuous emissions monitoring systems

• A system of emission allowances has been imposed

• These allowances can be traded or sold nationwide

• Bonus allowances are given to companies installing clean coal technology or using renewable energy sources

Title VPermit Program

• Permits are required by all major sources of air pollution and some smaller polluters, both for operating plants & new plants

• They include information on the type of pollutants emitted, how they’re controlled and how they will be monitored

• The EPA has the authority to fine violators

Title VIStratospheric Ozone

• 1978 – propellants in aerosol can were banned

• 1990 – schedule set for the phasing out of ozone-destroying chemicals

• The EPA has issued allowances for these substances in the mean time

• Recycling and labeling of these materials is required

• Service and maintenance of car air conditioners is strictly regulated

• New substitute products are being tested before being put into use

Title VII

• Covers enforcement provisions

Title VIII - IX

• Miscellaneous topics

• Greenhouse gases

• International issues

• Disadvantaged business concerns

End Legislation/Begin Sampling & Remediation Techniques

Sampling and Analysis of Emissions

• Ambient monitoring data allows us to see trends in air quality over time

• Provides baseline information

• Helps in developing computer models

• Help predict potential episodes

• Source emissions data is used to evaluate compliance

• Determines whether equipment is efficient and effective

• Hazardous pollutants are monitored at their source under the provisions of the NESHAPs standards

Monitoring Process

• Two parts – sampling and data management

• Sampling methods depend on the pollutant, its physical state and its expected concentration

• Concentrations are measured in mass per unit volume, usually micrograms per cubic meter or ug/m3

Calibration

• Checking and adjusting of instruments to insure quality control

• Comparing readings with a known standard

Quality Assurance

• Specific guidelines for analysis, calibration and calculation are listed as appendices of CFR 40 Part 50

• The EPA publishes a three volume Quality Assurance Handbook

• Agencies are required to provide a daily air quality index report in all urban areas with at least 500,000 people

The Gravimetric Approach

• Manual method used to measure particulate matter

• High volume method - catches material in a filter as it is drawn in by a blower

• The filter is weighed before and after

• Lead is collected in a similar fashion

• But must be separated from other particulates by dissolving it from the other particulates using acid

• The lead content of the solution is determined using an atomic absorption spectrometer

Carbon Monoxide Measurement

• An automated method involving a infrared spectrometric principle

• CO absorbs infrared radiation at characteristic wavelengths

• A sealed reference cell is compared to a sample cell through which the air passes

• When CO is present, it absorbs the radiation and the change is detected electronically

Ozone

• An automated method which involves gas phase chemiluminescence, chemical reactions that produce light

• Air is drawn through a tube containing ethylene which reacts with ozone emitting light that can be detected by a photomultiplier tube

Nitrogen oxide

• Detected in the same way as ozone

• But a different gas, ozone is used to create the reaction

Where Samples are Taken

• Is not specified in the Federal Reference Methods

• Downwind – upwind

• Proximity to trees, buildings and roadways

New Sources

• Where construction begins after the EPA publishes standards in the Federal Register

• The New Source Performance Standards, or NSPS, apply to specific sources

• The type of pollutants to be monitored, the allowable concentrations, kinds of monitoring required and the reference method used

Isokinetic Sampling

• Velocity of the gas at the sampling probe nozzle is the same as the velocity of the gas stream in the stack

Grab Technique

• Measures the volume of a sample by taking it at only one location, during one short continuous period of time

Integrated Sampling

• Takes samples from different locations over an extended period of time that is not necessarily continuous

Continuous Sampling

• Measuring a sample continuously using a source emission monitor

Air Pollution Control Techniques

• Equipment, processes or actions to reduce air pollution

• In serious nonattainment areas the Best Available Control Technology, BACT, will be required

• The Maximum Achievable Control Technologies, MACT, are required for sources emitting hazardous pollutants

Process Change

• Changing to low sulfur fuel

• Reformulated gasoline

• Alternative energy sources

• Housekeeping and maintenance

Emission Allowances

• An allowance is the limited authorization to emit one ton of SO2

• They can be traded or banked for future use

• Traded on the Chicago Board of Trade

• They are not a license to violate federal or state standards

• Companies without sufficient allowances are fined $2000 per ton for their excess emissions and will lose one allowance for each during the next year

• The bubble policy allow sources to be grouped to determine compliance

Control Equipment for Gaseous Emissions

• Adsorption

• Absorption

• Condensation

• Combustion

Adsorption

• Allowing the pollutant molecules to become attached to a solid surface like activated charcoal

• Can be regenerative or non-regenerative

Absorption

• Dissolving of a gaseous pollutant in a liquid solvent

• Spray towers, spray chambers, Venturi scrubbers and packed columns all maximize the opportunity for gas-liquid mixing

Condensation

• Gas or vapor is changed into a liquid by cooling or an increase in pressure

• Temperature reduction is the most cost effective

Combustion

• Combining a combustible material with oxygen producing heat and light

• Equipment includes flares, thermal incinerators and catalytic incinerators

Removing Particulates

• Efficiency of devices is calculated by taking the difference in the weight of particles in the air before and after, divided by the weight of particles when entering

• Control devices include settling chambers, cyclones, wet scrubbers, electrostatic precipitators, and fabric filters installed in a bag-house