AttainmentVolatile organic compounds (VOCs) are generally defined as any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates and ammonium carbonate, that participates in atmospheric photochemical reactions and has a vapor pressure of 0.01 kPa or greater at 77ºF (25ºC).
In more lay language, VOCs are organic chemicals that evaporate quickly at normal room temperature and pressure, and that have a high vapor pressure. Solvents, such as those used in many inkjet printing inks, are VOCs. They are designed to carry the ink to the substrate, and evaporate quickly, leaving only the ink film on the substrate.
Atmospheric photochemical reaction is the process by which ground-level ozone is formed. As VOCs are photochemically reactive, their use is controlled under air quality regulations.
Ozone is a gas composed of three atoms of oxygen. Ozone occurs both in the Earth's upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found:
Good ozone occurs naturally in the upper atmosphere, 6 to 30 miles above the Earth's surface, where it forms a protective layer that shields us from the sun's harmful ultraviolet rays. This beneficial ozone is gradually being destroyed by human-made chemicals. When the protective ozone layer has been significantly depleted — for example, over the North or South pole — it is sometimes called a "hole in the ozone."
In the Earth's lower atmosphere, near ground level, ozone is formed when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources chemically react in the presence of sunlight. Ozone at ground level is a harmful air pollutant.
Ground-level ozone is formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs), such as isopropyl alcohol, react in the atmosphere in the presence of sunlight. NOx and VOCs are called ozone precursors. Motor vehicle exhaust, industrial emissions, and chemical solvents (including many of those used in inkjet inks) are the major sources of these chemicals. Ozone pollution is a concern during the summer months when the weather conditions needed to form it — lots of sun, hot temperatures — normally occur. Although these precursors often originate in urban areas, winds can carry NOx hundreds of miles, causing ozone formation to occur in less populated regions as well.
While the two terms are often used interchangeably for general use, smog is more complex. Smog is primarily made up of ground-level ozone combined with other gases and particulate matter.
There is a record in the database for each county in the US. To find a specific record, use any of the following search methods:
The federal Environmental Protection Agency (EPA) has established an 8-hour ozone
standard. Because the formation of ozone depends upon human activity as well
as geography, ozone levels vary across the country. Compliance with the standard
is based on averaging air quality measurements over 8-hour blocks of time. The
level to which a county complies with the 8-hour ozone standard determines which
designation the EPA gives the country. There are three possible designations
for counties:
Once the EPA has provided its designations (last updated on April 15, 2004), the state, or local authority steps in to make regulations designed to reduce emissions of ozone-causing pollutants so that nonattainment or partial nonattainment areas will become attainment areas. The severity of the regulations — including restrictions on materials that ca be used as well as requirements for operating permits — generally coincides with the degree of nonattainment.
AttainmentAn attainment area is one that does not have an ground-level ozone pollution problem and, hence, meets the 8-hour ozone air quality standard. Typically, air quality regulations for counties that have been designated as attainment areas, will impact only businesses that emit more than 100 tons per year of VOCs.
NonattainmentThe Clean Air Act defines a nonattainment area as an area that is violating the national ambient air quality standard or contributing to a violation of the standard in a nearby area. Typically, air quality regulations for counties that have been designated as nonattainment areas, can impact businesses that emit as little as 10 tons per year of VOCs. The different levels of nonattainment, and the dates by which attainment must be achieved for each level, are listed in the chart below:
| Icon | Nonattainment Designation | Attainment Date |
|---|---|---|
 |
Basic (Subpart 1) | Up to 2009, may extend up to 2014. |
 |
Marginal | June 15, 2007 |
 |
Moderate | June 15, 2010 |
 |
Serious | June 15, 2013 |
 |
Severe | June 15, 2021 |
 |
Extreme | June 15, 2024 |
Partial
NonattainmentIn some cases, due to human activity and geography, there is more than one designation for a given county. Some counties may have part attainment and part nonattainment. Some counties may have two different nonattainment designations, such as part marginal and part serious.
If
a county is part of an early action compact, this icon will be displayed on the
county record.
Some geographic areas want to move even faster than required by the Clean Air Act. EPA is working with communities to get clean air as soon as possible by entering into Early Action Compacts to reduce ground-level ozone pollution.
Communities with Early Action Compacts will have plans in place to reduce air pollution at least two years earlier than required by the Clean Air Act. In December 2002, a number of states submitted compact agreements pledging to reduce emissions earlier than required for compliance with the 8-hour ozone standard. The states had to meet specific criteria and agreed to meet certain milestones.
As long as Early Action Compact Areas meet these milestones, the effective date of ozone nonattainment designations will be deferred. Thirty-three communities in 14 states have volunteered to participate in an Early Action Compact. If a county is part of an Early Action Compact Area, it is noted on the country record in the database.
The state air quality website offers general and background information on state air quality issues and links to other air quality websites.
The state air quality rules/regulations website provides the specific text of regulations that govern air quality in the state. Most of the websites also provide links to additional information.
The state air permitting information website provides information about the types of air permits required in the state, and the procedures for applying for a permit. Many states also have their permit applications available on-line.
Hazardous air pollutants (HAPs) or air toxics are those pollutants that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental effects. Air toxics may also cause adverse environmental and ecological effects. Most air toxics originate from human-made sources, including mobile sources (e.g., cars, trucks, construction equipment), stationary sources (e.g., factories, refineries, power plants), and indoor sources (e.g., some buildings materials and cleaning solvents).
In addition to the 188 hazardous air pollutants regulated federally under the Clean Air Act, some states regulate other air pollutants. State information can be found by clicking on the State Air Toxics Website link.
EPA regulates 188 specific hazardous air pollutants (HAPs). The list of HAPs is available at www.epa.gov/ttn/atw/188polls.html.
The regulatory threshold for HAPs emissions is 10 tons per year for any single HAP or 25 tons per year for any combination of HAPs.
Complete information on federal EPA HAPs is available at www.epa.gov/air/toxicair/index.html.
In most cases, air quality regulations are made at the state level. However, some counties maintain websites with air quality information.
In California, even though attainment or nonattainment designations are made by county, the rules and regulations are made by local air districts. Therefore, in the case of California, county records also identify the AQMD in which the county is located, and provide a link to the AQMD rules/regulations website.