FACT SHEET

PROPOSAL TO REVISE THE NATIONAL AMBIENT AIR Q UALITY STANDARDS

FOR OZONE

ACTION

• On June 20, 2007, EPA proposed to strengthen th e national ambient air quality standards for ground-level ozone, the primary component of smog. The proposed revisions reflect new

scientific evidence about ozone and its effects on people and public welfare.

• Breathing air containing ozone can reduce lung function, thereby a ggravating asthma or other respiratory conditions. Ozone expos ure has also been associated with increases in respiratory infection susceptibility, medici ne use by asthmatics, doctors’ visits, emergency department visits and hospital admissions. Ozone exposure also may contribute to premature death in people with heart and lung disease.

• Scientific evidence indicates th at adverse public health effects occurs following exposure to ozone at levels below the current standard, par ticularly in those with respiratory illnesses.

• In addition, new scientific eviden ce since the last review shows that repeated exposure to low levels of ozone damages vegetation, trees and cr ops leading to increased susceptibility to disease, damaged foliage, and reduced crop yields.

• EPA’s proposal would revise both ozone standards: the primary standard, desi gned to protect human health; and the secondary standard, designed to protec t welfare (such as vegetation and crops). The existing primary and secondary standards, set in 1997, are identical: an 8

- hour standard of 0.08 parts per million (ppm). (In practice, because of rounding, an area

meets the standard if ozone le vels are 0.084 ppm or lower.)

Proposed revisions to the primary standard

• EPA proposes to set the primary (health) st andard to a level within the range of 0.070-0.075 ppm (70 -75 ppb) The Agency al so requests comments on alternative levels of the 8-hour primary ozone standa rd, within a range from 0.060 ppm up to and including retention of th e current standard (0.084 ppm). (EPA also proposes to specify the level of the primary standard to the third decimal place, because today’s monitors can detect ozone that accurately.

Proposed revisions to the secondary standard

• EPA is proposing two options for the secondary standard:

• One option would establish a new form of standard designed specifically to protect sensitive plants from damage caused by repeated ozone exposure throughout the growing season. This cumula tive standard would add daily ozone concentrations across a three-month peri od. EPA is proposing to set the level of

the cumulative standard within th e range of 7 to 21 ppm-hours.

1• The other option would follow the curre nt practice of ma king the secondary standard identical to the pr oposed primary 8-hour standard.

• EPA will take public comment for 90 days following publication of the proposal in the Federal Register. The agency also will hold four public hearings on the proposal in: Los Angeles and Philadelphia on Aug. 30, a nd Chicago and Houston on Sept. 5.

• EPA will issue final standards by March 12, 2008.

OZONE AND PUBLIC HEALTH

• Exposures to ozone can:

o Reduce lung function, making it more difficu lt for people to breathe as deeply and vigorously as normal,

o Irritate the airways, causing coughing, sore or scratchy throat, pain when taking a deep breath and shortness of breath,

o Increase frequency of asthma attacks,

o Inflame and damage the lining of the lung,

o Increase susceptibility to respiratory infection, and

o Aggravate chronic lung diseases such as asthma, emphysema and bronchitis.

• In some people, these effects can lead to:

o Increased medicine use among asthmatics,

o More frequent doctors visits,

o School absences, and

o Increased emergency room visits and hospital admissions.

• Ozone may continue to cause lung damage ev en when the symptoms have disappeared.

• Breathing ozone may contribute to premature de ath in people with heart and lung disease.

OZONE AND THE ENVIRONMENT

• Ground-level ozone can have harmful effects on plants and ecosystems. When sufficient ozone enters the leaves of a plant, it can:

o Interfere with the ability of sensitive plan ts to produce and store food, making them more susceptible to certain diseases, ins ects, other pollutants, competition and harsh

weather.

o Visibly damage the leaves of trees and ot her plants, harming the appearance of urban vegetation, national parks, and recreation areas.

o Reduce forest growth and crop yields.

2DETERMINING COMPLIANCE: THE FORM OF THE STANDARDS

• When EPA sets air quality standards, it also mu st specify the measurement unit, or “form” of each standard, that the Agency will use to determine whether an area is meeting the

standards.

• For the primary ozone standard, an area meets the standard if the three-year average of the annual fourth-highest reading at a particular monitor is less than or equal to the level of the

standard.

• EPA is proposing a new and dist inct form for the secondary standard. The form, called W126, is designed to account for the cumulativ e effects of ozone on vegetation during the three months of the year when ozone concentr ations are highest. The form focuses on the highest exposure duri ng the growing season.

• If EPA finalizes the W126 option, an area woul d meet the secondary standard if the W126 value is less than or equal to the level of the standard. If the agency finalizes the section option proposed, compliance with the seconda ry standard would be based on compliance with the primary 8-hour standard.

BENEFITS AND COSTS

• While the Clean Air Act prohibits EPA from cons idering costs in setting or revising National Ambient Air Quality Standards, the Agency anal yzes the benefits and costs of meeting the standards in order to provide st ates and other stakeholders with the information necessary to assess the implications of meeti ng alternative standards. The analysis, which is required by Executive Order 12866, is based on guidance from the White House Office of Management and Budget. These analyses of benefits and co sts will be detailed in a Regulatory Impact Analysis to be released in the next few weeks.

• To estimate the benefits of meeting a standa rd, EPA utilizes a sophisticated peer-reviewed approach to modeling the relatio nship between air quality and h ealth and welfare effects, the air quality impacts of implementing future cont rol technologies, and the dollar values of public health improvements.

• To estimate the costs of meeting a standard, EPA uses several peer-reviewed approaches for modeling the cost of using both existing controls and controls that may be developed in the future for reducing NOx and VOCs .

3ESTIMATED TIMELINE FOR IMPLEMEN TING THE PROPOSED STANDARDS

• EPA will issue final standards by March 12, 2008. Based on that date, EPA estimates the following implementation schedule:

o By June 2009 : States make recommendations for ar eas to be designated attainment and

nonattainment.

o By June 2010 : EPA makes final designations of a ttainment and nonattainment areas. Those designations would become effective 60 days after publica tion in the Federal Register.

o 2013 : State Implementation Plans, outlining how states will reduce pollution to meet the standards, are due to EPA (three years after designations).

o 2013 to 2030: States are required to meet the st andard, with deadlines depending on the severity of the problem.

WHAT IS OZONE?

• Ozone is found in two regions of the Earth’s atmosphere – at ground level and in the upper regions of the atmosphere. Both types of ozone have the same chemical composition (O 3 ). While upper atmospheric ozone forms a protectiv e layer from the sun’s harmful rays, ground level ozone is the primary component of smog.

• Ground-level ozone is not emitted directly into the air, but forms through a reaction of nitrogen oxides (NOx) and volat ile organic compounds (VOCs) in the presence of sunlight.

• Emissions from industrial faciliti es and electric utilities, mo tor vehicle exhaust, gasoline vapors, and chemical solvents are the major man-made sources of NOx and VOCs.

• Because sunlight and hot weather accelerate its formation, ozone is mainly a summertime air pollutant. Both urban and rural areas can have high ozone levels, often due to transport of ozone or its precursors (NOx and VO Cs) from hundreds of miles away.

BACKGROUND ON THE NA TIONAL AIR QUALITY STANDARDS FOR OZONE

• The Clean Air Act requires EPA to set Nati onal Ambient Air Qua lity Standards (NAAQS) for pollutants considered harmful to public he alth and the environment. National standards exist for six pollutants: ozone, particulate ma tter, nitrogen oxides, carbon monoxide, sulfur dioxide, and lead.

4• The law also requires EPA to peri odically review the standards and their scientific basis to determine whether revisions are appropriate.

• EPA last updated the ozone standards in 1997. The decision to revise the standards was challenged in court by a number of parties a nd ultimately reached the U.S. Supreme Court. The Court unanimously upheld the constitutional ity of the 1970 Clean Air Act provision that authorizes EPA to set NAAQS to protect public health and welfar e. The Court also affirmed that the Clean Air Act requires EPA to set ambien t air quality standards, at levels necessary to protect the public health and welfare, without c onsidering the economic costs of implementing the standards.

HOW TO COMMENT

• EPA will accept public comments for 90 days after the proposed revisions to the ozone standards are published in the Federal Register.

• Comments should be identified by Docket ID No. EPA-HQ-OAR-2005 -0172 and submitted by one of the following methods:

o Federal eRulemaking Portal (http://www.regulations.gov),

o e-mail (a-and-r-docket@epa.gov),

o Mail (EPA Docket Center, Environmen tal Protection Agency, Mail code 6102T,

o 1200 Pennsylvania Avenue, NW, Washington, DC 20460), or

o Hand delivery (EPA Docket Center, E nvironmental Protection Agency, Room

o 3334, 1301 Constitution Avenue, NW, Washington, DC).

FOR MORE INFORMATION

• To download the Federal Register notice about the proposed revisi ons to the ozone standards, visit www.epa.gov/groundlevelozone.

• Today’s proposal and other background informati on are also available ei ther electronically at http://www.regulations.gov , EPA’s electronic public docket and comment system, or in hardcopy at the EPA Docket Ce nter’s Public Reading Room.

• The Public Reading Room is located in the EPA Headquarters Library, Room Number 3334 in the EPA West Building, located at 1301 Constitution Ave., NW, Washington, DC. Hours of operation are 8:30 a.m. to 4:30 p.m. eastern standard time, Monday through Friday, excluding federal holidays.

• Visitors are required to show photogra phic identification, pass through a metal detector, and sign the EPA visitor log. All visitor materials will be processed through an X-ray machine as well. Visitors will be provided a badge that must be visible at

all times.

• Materials for this action can be accesse d using Docket ID No. EPA-HQ-OAR- 2005-

0172.

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