Air Quality IndexHow 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 climateConcentration (quantity) and duration are determinants of level of harm

How Does AirPollution Affect Us?Humans breathe in 6-10 liters of air per minuteHarmful 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 pollutionAir pollution may also affect theHeartCirculatory systemImmune system

Who Does AirPollution Affect?The very young are at riskLungs are not fully developed until age 18They have a faster breathing rateThe very old are at riskMay have undiagnosed lung or heart diseasePollution can exacerbate these conditionsPersons with chronic illnesses, especially those with respiratory, circulatory, or cardiac disease, are also at risk

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

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

What Causes Air Pollution? NatureAir pollution may occur due to natural processesThis pollution is dispersed over a wide area, and is usually not as hazardous as other pollution

volcanoesfiresdustpollen & spores

What Else CausesAir Pollution?People! Air pollution may also occur due to human activitiesCalled anthropogenic sourcesStationary sources, such as power plants or industryMobile sources, such as vehicles

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 (O)Particulate Matter (Particle Pollution)< 2.5 microns< 10 micronsCarbon Monoxide (CO)Sulfur Dioxide (SO)Nitrogen Dioxide (NO)

How Values to Calculate AQI are GeneratedMonitors record the average concentration for each of the air pollutantsThe time recorded varies by pollutantIn some circumstances, models are used to determine values for AQI

How AQI is CalculatedAn equation is used with the pollution concentration data and an AQI break-point tableSee http://www.epa.gov/airnow/aqi_tech_assistance.pdf for detailsAQI is calculated for each pollutantThe pollutant with the highest AQI determines the level for the day, and is noted as the responsible pollutant

AQI ValuesAQI values range from 0-500The higher the AQI, the greater the air pollution and health concernsAn AQI of 100 corresponds to the national air quality standard for that pollutantA value 100 indicates air quality may be unhealthy for some groupsA value >300 represents very hazardous air quality

What are CommonAQI Levels?AQI levels are generally 0-100 in most U.S. communitiesAQI >100 may occur only a few times of year, if at allSome U.S. metropolitan areas have greater pollution and thus AQIs >100AQIs >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

AQI CategoriesAQI values are converted to a category for easier understanding by the publicCategories consider the public health impacts of the pollution levelA color code is used to associate the actions to be taken at that level

AQI Chart

AQI ReportingMetropolitan Statistical Areas (MSAs) with populations >350,000 are required by Federal law to report the AQI daily to the general public

AQI DistributionAQI may be distributed: To media NewspapersRadioTelevisionProvided as a recorded telephone messagePublished on an Internet site that is accessible to the public

The AQI ReportProvides data on current days air quality and may include the nexts days air quality forecastMUST include:Reporting areaReporting periodCritical pollutantAQI

The AQI ReportMUST Also Include...Information on specific health concerns for certain populationsDescriptor must be used: Good through HazardousColor Code must be noted: Green through MaroonCautions for sensitive groups for any pollutants with an AQI over 100

Pollutant Specific Sensitive Groups

If AQI >100...Then these sensitive groupsmust be cautioned:OzonePeople with lung disease, children, older adults, and people who are active outdoorsPM2.5People with heart or lung disease, children, and older adultsPM10People with heart or lung disease, children, and older adultsCOPeople with heart diseaseSOPeople with asthma

Action DaysAction Days are called when the AQI is in the unhealthy range.Individual agencies/cities determine at what level to call Action DaysSome use Unhealthy for Sensitive Groups or Code OrangeSensitive groups should avoid prolonged or heavy outdoor exertion outdoorsOther cities use Unhealthy or Code RedPeople should avoid prolonged or heavy outdoor exertion outdoors

Other Preventative ActionsHigh levels of AQI may trigger various restrictions or prohibitions by local governments to protect the public healthOfficials consider:Current pollutant concentrationsPrevailing weather conditionsForecasted weather conditions

Possible High AQI ActionsLevels above 200 may cause an Alert stageActivities restricted may include incinerator use or open burning of leaves or refuse

Possible High AQI ActionsLevels above 200 may cause an Alert stageActivities restricted may include incinerator use or open burning of leaves or refuseLevels above 300 may trigger a Warning stageIncinerator use may be prohibited, power plant operations cut back, specific manufacturing operations curtailed, and public driving limited with public transportation and carpooling encouraged

AQI Emergency ActionsLevels above 400 would be an EmergencyWould require most industrial and commercial activity to cease, and almost all private vehicle use to ceaseDeath would occur in some very sensitive individualsSensitive individuals might be hospitalizedHealthy persons would probably experience symptoms that would restrict normal activities

Seasonal Variations in AQI WinterCO may be highest level pollutantVehicle emission control systems do not operate as well in cold weatherLevels are generally highest during morning or evening rush hoursSummerVOCs and NOx form ozone more rapidly in the presence of heat and sunlightLevels peak in the afternoon

Smog/Ozone SeasonSmog/Ozone Season is generally May to SeptemberMarch 1- October 31 in GeorgiaOzone may not be reported in other months unless the level is high or the season is longer for that area

Ozone StandardsEPA strengthened air quality standards for ground-level ozone in March, 2008Ground-level ozone is a primary component of smogLower levels of ozone are now reported as unhealthy in AQI and daily smog forecasts

Particle Pollution MapsAvailable year-round for some citiesSome state and local agencies are not yet participating in this program

EPA Proposal for Stronger NO Air Quality Standards06/29/2009 Proposal to update standards to reflect newest findings of NO exposure on public healthPropose to monitor NO levels for a shorter time periodRecent research indicates that short-term exposure to high NO 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 residentsOften a higher concentration of NO near major roadways than at monitoring stationsProposal decision on new standard required by Jan. 22, 2010

Other ConsiderationsAQI levels are not the only factors in determining how healthy the air is in a place- other factors include:Transportation patternsIndustrial compositionLocation of monitoring sitesWeather patterns, such as inversions

One Last Consideration...Synergism of pollutants has not been fully studiedCombinations of pollutants may increase harmful effectsCombinations of pollutants may cause harmful effects to occur at lower levelsCombinations of pollutants may cause new or currently unknown problemsEPA will likely modify the AQI as more research is available in this area

Air Quality Index (AQI) SummaryThe AQI is:Used to protect public healthUsed to determine appropriate activities for people, industry, and commerceCalculated from monitored values of 5 major pollutantsAn effective tool to determine how well Clean Air Act standards are being met by our communities