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Air Quality Index

Air Quality Index. How Healthy is the Air You Breathe?. Air Pollution. Definition: The presence of one or more harmful chemicals in the atmosphere. Air Pollution. May cause harm to people, animals, vegetation, or materials, or may alter climate

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Air Quality Index

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  1. Air Quality Index • How Healthy is the Air You Breathe?

  2. Air Pollution... • Definition: The presence of one or more harmful chemicals in the atmosphere

  3. Air Pollution... • May cause harm to people, animals, vegetation, or materials, or may alter climate • Concentration (quantity) and duration are determinants of level of harm

  4. How Does AirPollution Affect Us? • Humans breathe in 6-10 liters of air perminute • Harmful chemicals may be absorbed quickly without us being aware • Air pollutants come into contact first with our respiratory systems, so the lungs are most affected by this pollution • Air pollution may also affect the • Heart • Circulatory system • Immune system

  5. Who Does AirPollution Affect? • The very young are at risk • Lungs are not fully developed until age 18 • They have a faster breathing rate • The very old are at risk • May have undiagnosed lung or heart disease • Pollution can exacerbate these conditions • Persons with chronic illnesses, especially those with respiratory, circulatory, or cardiac disease, are also at risk

  6. Does Air Pollution Affect Anyone Else? • Yes,EVERYONE! • Even healthy persons can be affected when they exercise outdoors, or if the concentration of pollutants is very high

  7. How Do We Know When the Air is Polluted and Unsafe? • Air pollution may be colorless or odorless, thus hard to detect • Air pollution may be obvious, as a brown or yellow haze, or with particulates in the air • By the time pollution is obvious, it may be at very unhealthy levels

  8. What Causes Air Pollution? Nature • Air pollution may occur due to natural processes • This pollution is dispersed over a wide area, and is usually not as hazardous as other pollution

  9. What Else CausesAir Pollution? • People! Air pollution may also occur due to human activities • Called ‘anthropogenic’ sources • Stationary sources, such as power plants or industry • Mobile sources, such as vehicles

  10. Because it is Sometimes Difficult to Know... • To protect public health, the Environmental Protection Agency (EPA) monitors 5 air pollutants in what is called the ‘Air Quality Index’ (AQI) • Ground-level Ozone (O₃) • Particulate Matter (Particle Pollution) • < 2.5 microns • < 10 microns • Carbon Monoxide (CO) • Sulfur Dioxide (SO₂) • Nitrogen Dioxide (NO₂)

  11. How Values to Calculate AQI are Generated • Monitors record the average concentration for each of the air pollutants • The time recorded varies by pollutant • In some circumstances, models are used to determine values for AQI

  12. How AQI is Calculated • An equation is used with the pollution concentration data and an AQI break-point table • See http://www.epa.gov/airnow/aqi_tech_assistance.pdf for details • AQI is calculated for each pollutant • The pollutant with the highest AQI determines the level for the day, and is noted as the responsible pollutant

  13. AQI Values • AQI values range from 0-500 • The higher the AQI, the greater the air pollution and health concerns • An AQI of 100 corresponds to the national air quality standard for that pollutant • A value <100 is generally considered satisfactory and not a health hazard • A value >100 indicates air quality may be unhealthy for some groups • A value >300 represents very hazardous air quality

  14. What are CommonAQI Levels? • AQI levels are generally 0-100 in most U.S. communities • AQI >100 may occur only a few times of year, if at all • Some U.S. metropolitan areas have greater pollution and thus AQIs >100 • AQIs >200 are rare in the U.S. • In other countries with dense population areas, uncontrolled sources of pollution, and fewer governmental emission restrictions, AQIs are frequently >250

  15. AQI Categories • AQI values are converted to a category for easier understanding by the public • Categories consider the public health impacts of the pollution level • A color code is used to associate the actions to be taken at that level

  16. AQI Chart

  17. AQI Reporting • Metropolitan Statistical Areas (MSAs) with populations >350,000 are required by Federal law to report the AQI daily to the general public

  18. AQI Distribution • AQI may be distributed: • To media • Newspapers • Radio • Television • Provided as a recorded telephone message • Published on an Internet site that is accessible to the public

  19. The AQI Report • Provides data on current day’s air quality and may include the next’s day’s air quality forecast • MUST include: • Reporting area • Reporting period • Critical pollutant • AQI

  20. The AQI ReportMUST Also Include... • Information on specific health concerns for certain populations • Descriptor must be used:“Good” through “Hazardous” • Color Code must be noted:“Green” through “Maroon” • Cautions for sensitive groups for any pollutants with an AQI over 100

  21. Pollutant Specific Sensitive Groups

  22. Action Days • ‘Action Days’ are called when the AQI is in the unhealthy range. • Individual agencies/cities determine at what level to call ‘Action Days’ • Some use ‘Unhealthy for Sensitive Groups’ or Code Orange • Sensitive groups should avoid prolonged or heavy outdoor exertion outdoors • Other cities use ‘Unhealthy’ or Code Red • People should avoid prolonged or heavy outdoor exertion outdoors

  23. Other Preventative Actions • High levels of AQI may trigger various restrictions or prohibitions by local governments to protect the public health • Officials consider: • Current pollutant concentrations • Prevailing weather conditions • Forecasted weather conditions

  24. Possible High AQI Actions • Levels above 200 may cause an “Alert” stage • Activities restricted mayinclude incinerator use oropen burning of leaves orrefuse

  25. Possible High AQI Actions • Levels above 200 may cause an “Alert” stage • Activities restricted may include incinerator use or open burning of leaves or refuse • Levels above 300 may trigger a “Warning” stage • Incinerator use may be prohibited, power plant operations cut back, specific manufacturing operations curtailed, and public driving limited with public transportation and carpooling encouraged

  26. AQI Emergency Actions • Levels above 400 would be an “Emergency” • Would require most industrial and commercial activity to cease, and almost all private vehicle use to cease • Death would occur in some very sensitive individuals • Sensitive individuals might be hospitalized • Healthy persons would probably experience symptoms that would restrict normal activities

  27. Seasonal Variations in AQI • Winter • CO may be highest level pollutant • Vehicle emission control systems do not operate as well in cold weather • Levels are generally highest during morning or evening rush hours • Summer • VOCs and NOx form ozone more rapidly in the presence of heat and sunlight • Levels peak in the afternoon

  28. Smog/Ozone ‘Season’ • Smog/Ozone ‘Season’ is generally May to September • March 1- October 31 in Georgia • Ozone may not be reported in other months unless the level is high or the ‘season’ is longer for that area

  29. Ozone Standards • EPA strengthened air quality standards for ground-level ozone in March, 2008 • Ground-level ozone is a primary component of smog • Lower levels of ozone are now reported as unhealthy in AQI and daily smog forecasts

  30. Particle Pollution Maps • Available year-round for some cities • Some state and local agencies are not yet participating in this program

  31. EPA Proposal for Stronger NO₂ Air Quality Standards • 06/29/2009 Proposal to update standards to reflect newest findings of NO₂ exposure on public health • Propose to monitor NO₂ levels for a shorter time period • Recent research indicates that short-term exposure to high NO₂ levels, ranging from 30 minutes to 24 hours, may increase respiratory problems, especially in persons with asthma, children, or the elderly. • Propose to monitor within 50 meters of major roadways in cities with at least 350,000 residents • Often a higher concentration of NO₂ near major roadways than at monitoring stations • Proposal decision on new standard required by Jan. 22, 2010

  32. Other Considerations • AQI levels are not the only factors in determining how healthy the air is in a place- other factors include: • Transportation patterns • Industrial composition • Location of monitoring sites • Weather patterns, such as inversions

  33. One Last Consideration... • Synergism of pollutants has not been fully studied • Combinations of pollutants may increase harmful effects • Combinations of pollutants may cause harmful effects to occur at lower levels • Combinations of pollutants may cause new or currently unknown problems • EPA will likely modify the AQI as more research is available in this area

  34. Air Quality Index (AQI) Summary • The AQI is: • Used to protect public health • Used to determine appropriate activities for people, industry, and commerce • Calculated from monitored values of 5 major pollutants • An effective tool to determine how well Clean Air Act standards are being met by our communities

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