1. What are the sources of air pollution?
2. What are the environmental and health effects of air pollution?
3. How can air pollution be prevented?
4. What is the AQI?
5. What do the AQI colors mean?
6. What should I do when the Air Quality Index is high?

Q: What are the sources of air pollution?

A: The air we breathe in the United States is polluted with nearly 200 million tons of toxic emissions each year. Since air pollution is not confined to a specific area and everyone is affected, it is the nation's largest environmental health risk.

Air pollution is the contamination of the atmosphere by gaseous, liquid, or solid wastes that can endanger the health of human beings, plants, and animals, or that can damage materials, reduce visibility, or produce undesirable odors. Any substance that is present in or released to the atmosphere that results in adverse effects on human/environmental health is considered to be an air pollutant.

It is important to note that there are two categories of air pollutants: primary and secondary. Primary pollutants are emitted directly into the atmosphere. This includes such pollutants as carbon dioxide, carbon monoxide, hydrocarbons, and particulates. Secondary pollutants are primary pollutants that, once in the atmosphere, react with other primary pollutants or atmospheric compounds. A prime example of a secondary pollutant is acid rain, which is formed when sulfur dioxide or nitrogen oxides react with water.

Air pollution can originate from many different sources. Some sources are classified as stationary and include: factories, power plants, and smelters. Other sources of pollution are classified as mobile sources and include cars, buses, planes, trucks, lawn mowers, and trains. Natural sources include wildfires, windblown dust, and volcanic eruptions. Air pollution is created by different sources, but 90 percent of air pollution originates with people. Industries, power plants, motor vehicles, agriculture processes, open burning, and many consumer products are all contributors. This means that everyone businesses and consumers contributes to the problem.

Q: What are the environmental and health effects of air pollution?

A:

• SO₂ Sulfur Dioxide:
  High concentrations of SO₂ can result in temporary breathing impairment for asthmatic children and adults who are active outdoors. Short-term exposures of asthmatic individuals to elevated SO₂ levels while at moderate exertion may result in reduced lung function that may be accompanied by such symptoms as wheezing, chest tightness, or shortness of breath. Other effects that have been associated with longer-term exposures to high concentrations of SO₂, in conjunction with high levels of PM, include respiratory illness, alterations in the lungs' defenses, and aggravation of existing cardiovascular disease. The subgroups of the population that may be affected under these conditions include individuals with cardiovascular disease or chronic lung disease, as well as children and the elderly.

  Together, SO₂ and NOx are the major precursors to acidic deposition (acid rain), which is associated with the acidification of soils, lakes, and streams, accelerated corrosion of buildings and monuments, and reduced visibility. Sulfur dioxide also is a major precursor to PM-2.5, which is a significant health concern as well as a main pollutant that impairs visibility.

• O₃ Ozone:
  Short-term (1-3 hours) and prolonged (6-8 hours) exposures to ground-level ozone have been linked to a number of health effects of concern.

  For example, increased hospital admissions and emergency room visits for respiratory causes have been associated with ambient ozone exposures. Repeated exposures to ozone can make people more susceptible to respiratory infection, result in lung inflammation, and aggravate pre-existing respiratory diseases such as asthma.

  Other health effects attributed to ozone exposures include significant decreases in lung function and increased respiratory symptoms such as chest pain and cough. These effects generally occur while individuals are engaged in moderate or heavy exertion.

  Children active outdoors during the summer when ozone levels are at the highest are most at risk of experiencing such effects. Other at-risk groups include adults who are active outdoors, (e.g. outdoor workers) and individuals with pre-existing respiratory disease such as asthma and chronic obstructive lung disease. In addition, longer-term exposures to moderate levels of ozone present the possibility of irreversible changes in the lungs, which could lead to premature aging of the lungs and/or chronic respiratory illnesses.

  Ground-level ozone also affects vegetation and ecosystems, leading to reductions in agricultural and commercial forest yields, reduced growth and survivability of tree seedlings, and increased plant susceptibility to disease, pests, and other environmental stresses (e.g., harsh weather). In long-lived species, these effects may become evident only after several years or even decades, thus having the potential for long-term effects on forest ecosystems. Ground-level ozone damage to the foliage of trees and other plants also can decrease the aesthetic value of ornamental species as well as the natural beauty of our parks and recreation areas.

• PM-10 and PM 2.5 Inhalable Particulate Matter:
  Inhalable Particulate Matter includes both fine and coarse particles. These particles can accumulate in the respiratory system and are associated with numerous health effects. Exposure to coarse particles is primarily associated with the aggravation of respiratory conditions, such as asthma.

  Fine particles are most closely associated with such health effects as increased hospital admissions and emergency room visits for heart and lung disease, increased respiratory symptoms and disease, decreased lung function, and even premature death. Sensitive groups that appear to be at greatest risk to such effects include the elderly, individuals with cardiopulmonary disease, such as asthma, and children. In addition to health problems, Particulate Matter is the major cause of reduced visibility in many parts of the United States. Airborne particles also can cause damage to paints and building materials.

• NOX Nitrogen Oxides:
  Short-term exposures (less than 3 hours) to nitrogen dioxide (NO₂) concentrations may lead to changes in airway responsiveness and lung function in individuals with pre-existing respiratory illnesses and increases in respiratory illnesses in children (5-12 years old).

  Long-term exposures to NO₂ may lead to increased susceptibility to respiratory infection and may cause alterations in the lung. Atmospheric transformation of NOx can lead to the formation of ozone and nitrogen-bearing particles (most notably in some western urban areas) that are both associated with adverse health effects.

  Nitrogen oxides also contribute to the formation of acid rain. Nitrogen oxides contribute to a wide range of environmental effects, including potential changes in the composition and competition of some species of vegetation in wetland and terrestrial systems, visibility impairment, acidification of freshwater bodies, eutrophication (explosive algae growth leading to a depletion of oxygen in the water) of estuarine and coastal waters (e.g., Chesapeake Bay), and increases in levels of toxins harmful to fish and other aquatic life.

• CO Carbon Monoxide:
  Carbon monoxide enters the bloodstream through the lungs and reduces oxygen delivery to the body's organs and tissues. The health threat from lower levels of CO is most serious for those who suffer from cardiovascular disease, such as angina pectoris. At much higher levels of exposure, CO can be poisonous and even healthy individuals may be affected. Visual impairment, reduced work capacity, reduced manual dexterity, poor learning ability, and difficulty in performing complex tasks are all associated with exposure to elevated CO levels.

Q: How can air pollution be prevented?

A: These easy strategies will help reduce the harmful vapors that react in sunlight to create air pollution:

At Home

• Tightly cap all solvents (paint thinners and strippers, degreasers, and some cleaning products). Solvents contain pollution-causing vapors.
• Postpone painting, stripping, and refinishing projects to avoid the morning and mid-day summertime heat. Better yet, wait until the Fall or Spring.
• Use water-based products (paints, stains and sealants).

In the Yard

• Delay mowing your lawn on warm sunny days. Instead mow in the evening or cool cloudy days.
• Avoid using high-emitting, gasoline-powered yard equipment. Electric alternatives are an efficient, environmentally friendly alternative.
• Use an electric starter or a "charcoal chimney" to start your barbeque grill. Lighter fluid contains a lot of harmful vapors that escape into our air and contribute to summertime air pollution.

On the Go

• Stop at the click when refueling your car. Overfilling your tank often results in fuel spills and always allows unnecessary pollution-causing vapors to escape into our air.
• Refuel in the evenings after dusk. By refueling after the sun goes down, fuel vapors do not have as much of a chance to "cook" in the mid-day sun and become harmful ground-level ozone.
• Maintain your vehicle. A poorly maintained vehicle can pollute as much as 25 times more than a well-maintained vehicle.

Q: What is the AQI?

A: Please go to http://www.epa.gov/airnow/aqibroch/aqi.html#2 for information about AQI.

Q: What do the AQI colors mean?

A: Please go to http://www.epa.gov/airnow/aqibroch/aqi.html#5 for information about the AQI colors.

Q: What should I do when the Air Quality Index is high?

A: The new Air Quality Index regulations (Part III, 40 CFR Part 58, Air Quality Index Reporting; Final Rule) came into effect on August 4, 1999. The Environmental Protection Agency revised its Air Quality Index to enhance the public's understanding of air pollution across the nation. Previously known as the Pollutant Standards Index, this uniform air quality index is used by state and local agencies to report on daily air quality to the public.

The AQI is a subpart of the new EMPACT program. EMAPCT stands for Environmental Monitoring for Public Access and Community Tracking. It is a new approach to working with communities to collect, manage, and present environmental information. It is an innovative effort to provide information on environmental conditions to the public in near real time. One of the strengths of EMPACT is that it encourages project partners to develop new and creative approaches of bringing environmental information to the public. Much of what EMPACT is doing has never been done before.

The Air Quality Index system reports ground level ozone, PM-10 (particulate matter smaller than 10 microns), PM-2.5 (particulate matter smaller than 2.5 microns), carbon monoxide, nitrogen dioxide and sulfur dioxide. All six pollutants can potentially endanger human health. A federal National Ambient Air Quality Standard defines the maximum levels each pollutant can reach before unhealthy conditions exist.

• Carbon Monoxide (CO)
  9 parts per million averaged over a 8-hour period
  35 parts per million averaged over a 1-hour period
• Nitrogen Dioxide (NO₂)
  0.053 parts per million averaged over the annual arithmetic mean
• Lead (Pb)
  1.5 micrograms per cubic meter of air per quarterly average
• Ozone (O₃)
  0.08 parts per million averaged over a 8-hour period
  0.12 parts per million averaged over a 1-hour period
• Particulate <10 Micrometers (PM-10)
  150 micrograms per cubic meter of air per a 24-hour period
• Particulate <2.5 Micrometers (PM-2.5)
  65 micrograms per cubic meter of air per a 24-hour period
• Sulfur Dioxide SO₂
  0.14 parts per million averaged over a 24-hour period

After analyzing current data, division staff converts the information about the individual pollutant concentrations into numbers on a scale the AQI scale. The National Ambient Air Quality Standard for each pollutant equals 100 on the Air Quality Index scale. Air Quality Index reports greater than 100 generally indicate exceedances of a pollutant's standard. The higher the Air Quality Index reading is, the worse the air quality. The Air Quality Index scale is described by six air quality categories.

Air Quality Index Detailed

• AQI 0-50
  Descriptor: Good
  Color: Green
  O₃ (ppm) 8-hr: 0.000 - 0.064
  O₃ (ppm) 1-hr: NA
  PM (2.5) (ug/m3): 0.0 - 15.4
  PM (10) (ug/m3): 0 - 54
  CO (ppm): 0.0 - 4.4
  SO₂ (ppm): 0.000 - 0.034
  NO₂ (ppm): NA
  General Health Effects: None
  Course of Action: Have a great day!



• AQI 51-100
  Descriptor: Moderate
  Color: Yellow
  O₃ (ppm) 8-hr: 0.065 - 0.084
  O₃ (ppm) 1-hr: NA
  PM (2.5) (ug/m3): 15.5 - 40.4
  PM (10) (ug/m3): 55 - 154
  CO (ppm): 4.5 - 9.4
  SO₂ (ppm): 0.035 - 0.144
  NO₂ (ppm): NA
  General Health Effects:
  CO none
  NO₂ none
  Ozone highly sensitive individuals may experience respiratory symptoms
  PM10 none
  PM2.5 none
  SO₂ none
  Course of Action:
  CO none
  NO₂ nothing
  Ozone highly sensitive individuals should consider limiting prolonged outdoor exertion
  PM10 nothing
  PM2.5 nothing
  SO₂ nothing



• AQI 101-150
  Descriptor: Unhealthy
  Color: Orange
  O₃ (ppm) 8-hr: 0.085 - 0.104
  O₃ (ppm) 1-hr: 0.125 - 0.164
  PM (2.5) (ug/m3): 40.5 - 65.4
  PM (10) (ug/m3): 155 - 254
  CO (ppm): 9.5 - 12.4
  SO₂ (ppm): 0.145 - 0.224
  NO₂ (ppm): NA
  General Health Effects:
  CO increasing likelihood of reduced exercise tolerance due to increased cardiovascular symptoms, such as chest pain, in people with cardiovascular disease
  NO₂ none
  Ozone increasing likelihood of respiratory symptoms and breathing discomfort in active children, adults and people with respiratory disease, such as asthma
  PM-10 increasing likelihood of respiratory symptoms and aggravation of lung disease, such as asthma
  PM-2.5 increasing likelihood of respiratory symptoms in sensitive individuals, aggravation of heart and lung disease and premature mortality in persons with cardiopulmonary disease and the elderly
  SO₂ increasing likelihood of respiratory symptoms, such as chest tightness and breathing discomfort, in people with asthma
  Course of Action:
  CO people with cardiovascular disease, such as angina, should limit heavy exertion and avoid sources of CO, such as heavy traffic
  NO₂ nothing
  Ozone - active children, adults and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion
  PM-10 people with respiratory disease, such as asthma, should limit outdoor exertion
  PM-2.5 people with respiratory or heart disease, the elderly and children should limit outdoor exertion
  SO₂ people with asthma should consider limiting outdoor exposure



• AQI 151-200
  Descriptor: Unhealthy
  Color: Red
  O₃ (ppm) 8-hr: 0.105 - 0.124
  O₃ (ppm) 1-hr: 0.165 - 0.204
  PM (2.5) (ug/m3): 65.5 - 150.4
  PM (10) (ug/m3): 255 - 354
  CO (ppm): 12.5 - 15.4
  SO₂ (ppm): 0.225 - 0.304
  NO₂ (ppm): NA
  General Health Effects:
  CO reduced exercise tolerance due to increased cardiovascular symptoms, such as chest pain, in people with cardiovascular disease
  NO₂ none
  Ozone greater likelihood of respiratory symptoms and breathing difficulty in active children, adults and people with respiratory disease, such as asthma; possible respiratory effects in general population
  PM10 increasing likelihood of respiratory symptoms and aggravation of lung disease, such as asthma; possible respiratory effects in general population
  PM2.5 increased aggravation of lung disease and premature mortality in persons with cardiopulmonary disease and the elderly; possible respiratory effects in general population
  SO₂ increased respiratory symptoms, such as chest tightness and wheezing in people with asthma; possible aggravation of heart or lung disease
  Course of Action:
  CO people with cardiovascular disease, such as angina, should limit moderate exertion and avoid sources of CO, such as heavy traffic
  NO₂ nothing
  Ozone active children, adults and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion; everyone else, especially children, should limit prolonged outdoor exertion
  PM10 people with respiratory disease, such as asthma, should limit outdoor exertion; everyone else, especially children, should limit prolonged outdoor exertion
  PM2.5 people with respiratory or heart disease, the elderly and children should avoid prolonged outdoor exertion; everyone else should limit prolonged exertion
  SO₂ children, asthmatics, and people with heart or lung disease should limit outdoor exertion



• AQI 201-300
  Descriptor: Very Unhealthy
  Color: Purple
  O₃ (ppm) 8-hr: 0.125 - 0.374
  O₃ (ppm) 1-hr: 0.205 - 0.404
  PM (2.5) (ug/m3): 150.5 - 250.4
  PM (10) (ug/m3): 355 - 424
  CO (ppm): 15.5 - 30.4
  SO₂ (ppm): 0.305 - 0.604
  NO₂ (ppm): 0.65 - 1.24
  General Health Effects:
  CO significant aggravation of cardiovascular symptoms, such as chest pain, in people with cardiovascular disease
  NO₂ increasing likelihood of respiratory symptoms and breathing discomfort in children and people with respiratory disease, such as asthma
  Ozone increasingly severe symptoms and impaired breathing likely in active children, adults and people with respiratory disease, such as asthma; Increasing likelihood of respiratory effects in general population
  PM10 significant increase in respiratory symptoms and aggravation of lung disease, such as asthma; increasing likelihood of respiratory effects in general population
  PM2.5 significant aggravation of lung or heart disease and premature mortality in persons with cardiopulmonary disease and the elderly; significant increase in respiratory effects in general population
  SO₂ significant increase in respiratory symptoms, such as wheezing and shortness of breath, in people with asthma; possible aggravation of heart or lung disease
  Course of Action:
  CO people with cardiovascular disease, such as angina, should avoid exertion and avoid sources of CO, such as heavy traffic
  NO₂ children and people with respiratory disease, such as asthma, should limit heavy outdoor exertion
  Ozone active children, adults and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion
  PM10 people with respiratory disease, such as asthma, should avoid any outdoor activity; everyone else, especially the elderly and children, should limit outdoor exertion
  PM2.5 people with respiratory or heart disease, the elderly and children should avoid any outdoor activity; everyone else avoid prolonged exertion
  SO₂ children, asthmatics, and people with heart or lung disease should avoid outdoor exertion; everyone else should limit outdoor exertion




• AQI 301-400
  Descriptor: Hazardous
  Color: Maroon
  O₃ (ppm) 8-hr: NA
  O₃ (ppm) 1-hr: 0.405 - 0.504
  PM (2.5) (ug/m3): 250.5 - 350.4
  PM (10) (ug/m3): 425 - 504
  CO (ppm): 30.5 - 40.4
  SO₂ (ppm): 0.605 - 0.804
  NO₂ (ppm): 1.25 - 1.64
  General Health Effects:
  CO serious aggravation of cardiovascular symptoms, such as chest pain, in people with cardiovascular disease; impairment of strenuous activities in general population
  NO₂ greater likelihood of respiratory symptoms and breathing difficulty in children and people with respiratory disease, such as asthma
  Ozone severe respiratory effects and impaired breathing likely in active children, adults and people with respiratory disease, such as asthma; Increasingly severe respiratory effects in general population
  PM-10 serious risk of respiratory symptoms and aggravation of lung disease, such as asthma; respiratory effects likely in general population
  PM-2.5 serious aggravation of lung or heart disease and premature mortality in persons with cardiopulmonary disease and the elderly; serious risk of respiratory effects in general population
  SO₂ severe respiratory symptoms, such as wheezing and shortness of breath, in people with asthma; increased aggravation of heart or lung disease; possible respiratory effects in general population
  Course of Action:
  CO people with cardiovascular disease, such as angina, should avoid exertion and avoid sources of CO, such as heavy traffic; everyone else should limit heavy exertion
  NO₂ children and people with respiratory disease, such as asthma, should limit moderate or heavy outdoor exertion
  Ozone everyone should avoid all outdoor exertion
  PM10 everyone should avoid any outdoor exertion; people with respiratory disease, such as asthma, should remain indoors
  PM2.5 everyone should avoid any outdoor exertion; people with respiratory disease, such as asthma, should remain indoors
  SO₂ children, asthmatics, and people with heart or lung disease should remain indoors; everyone else should avoid outdoor exertion




• AQI 401-500
  Descriptor: Hazardous
  Color: Maroon
  O₃ (ppm) 8-hr: NA
  O₃ (ppm) 1-hr: 0.505 - 0.604
  PM (2.5) (ug/m3): 350.5 - 500.4
  PM (10) (ug/m3): 505 - 604
  CO (ppm): 40.5 - 50.4
  SO₂ (ppm): 0.805 - 1.004
  NO₂ (ppm): 1.65 - 2.04
  General Health Effects:
  CO serious aggravation of cardiovascular symptoms, such as chest pain, in people with cardiovascular disease; impairment of strenuous activities in general population
  NO₂ greater likelihood of respiratory symptoms and breathing difficulty in children and people with respiratory disease, such as asthma
  Ozone severe respiratory effects and impaired breathing likely in active children, adults and people with respiratory disease, such as asthma; Increasingly severe respiratory effects in general population
  PM-10 serious risk of respiratory symptoms and aggravation of lung disease, such as asthma; respiratory effects likely in general population
  PM-2.5 serious aggravation of lung or heart disease and premature mortality in persons with cardiopulmonary disease and the elderly; serious risk of respiratory effects in general population
  SO₂ severe respiratory symptoms, such as wheezing and shortness of breath, in people with asthma; increased aggravation of heart or lung disease; possible respiratory effects in general population
  Course of Action:
  CO people with cardiovascular disease, such as angina, should avoid exertion and avoid sources of CO, such as heavy traffic; everyone else should limit heavy exertion
  NO₂ children and people with respiratory disease, such as asthma, should limit moderate or heavy outdoor exertion
  Ozone everyone should avoid all outdoor exertion
  PM-10 everyone should avoid any outdoor exertion; people with respiratory disease, such as asthma, should remain indoors
  PM-2.5 everyone should avoid any outdoor exertion; people with respiratory disease, such as asthma, should remain indoors
  SO₂ children, asthmatics, and people with heart or lung disease should remain indoors; everyone else should avoid outdoor exertion