How Is Air Quality Measured? | NOAA SciJinks

Air quality is measured with the Air Quality Index, or AQI. The AQI works sort of like a thermometer that runs from 0 to 500 degrees. However, instead of ... Atmosphere HowIsAirQualityMeasured? TheShortAnswer: AirqualityismeasuredwiththeAirQualityIndex,orAQI.TheAQIworkslikeathermometerthatrunsfrom0to500degrees.However,insteadofshowingchangesinthetemperature,theAQIisawayofshowingchangesintheamountofpollutionintheair. AphotographshowingsmogoverdowntownLosAngeles.Credit:PublicDomain Airqualityisameasureofhowcleanorpollutedtheairis.Monitoringairqualityisimportantbecausepollutedaircanbebadforourhealth—andthehealthoftheenvironment. AirqualityismeasuredwiththeAirQualityIndex,orAQI.TheAQIworkssortoflikeathermometerthatrunsfrom0to500degrees.However,insteadofshowingchangesinthetemperature,theAQIisawayofshowingchangesintheamountofpollutionintheair. Whatisintheair? TheairinouratmosphereismostlymadeupoftwogasesthatareessentialforlifeonEarth:nitrogenandoxygen.However,theairalsocontainssmalleramountsofmanyothergasesandparticles.AQItracksfivemajorairpollutants: Groundlevelozone Carbonmonoxide Sulfurdioxide Nitrogendioxide Airborneparticles,oraerosols GroundlevelozoneandairborneparticlesarethetwoairpollutantsthatposethegreatestrisktohumanhealthintheUnitedStates.Theyarealsothetwoofthemainingredientsinsmog,atypeofairpollutionthatreducesvisibility. Whataresomethingsthatcausebadairquality? Ozoneisagasyou’veprobablyheardofasalayerhighupinEarth’satmosphere.Thisozonelayerisagoodthing—ithelpsblockusfromtheSun’sharmfulradiation.However,groundlevelozoneisbadforhumanhealth.Itiscreatedwhensunlightreactswithcertainchemicalemissions(forexamplenitrogendioxide,carbonmonoxideandmethane).Thesechemicalscancomefromindustrialfacilities,carexhaust,gasolinevaporsandothersources. Airborneparticlesaresolidandliquiddropletssuspendedintheair.Theseparticlesbecomeairborneatconstructionsites,smokestacks,carexhaustpipes,wildfires,volcanoesandmanyotherplaces,too.Theparticlescanalsobeformedfromchemicalreactionsintheatmosphere. Whenisairqualitybadenoughthatyoushouldstayinside? AnAQIunder50meansthattheairqualityisgood.AtthislowAQIlevel,apersoncanspendtimeoutdoorsandairpollutionwillposeverylittlerisktotheirhealth.AstheAQInumberincreases,sodoestherisktohumanhealth.(SeethechartbelowforasummaryoftheAQIlevelsofhealthconcern.) AirqualityismeasuredinAirQualityIndexvalues.Source:Airnow.gov Wheredoesinformationaboutairqualitycomefrom? InstrumentsonthegroundandsatellitesorbitingEarthcollectinformationaboutwhatisinourair.Forexample,satellitesinNOAA’sGOES-R(shortforGeostationaryOperationalEnvironmentalSatellites-R)Seriesmonitortheparticlepollutioninouratmosphere. TheJointPolarSatelliteSystem(JPSS)alsocollectsinformationaboutparticlesinourair.Theseparticlesincludesmokeparticlesfromwildfires;airbornedustduringdustandsandstorms;urbanandindustrialpollution;andashfromeruptingvolcanoes.GroundlevelozonecanalsobemeasuredbytheJPSSseriesofsatellites. GOES-RSeriessatellitescanprovideparticlepollutionmeasurementsapproximatelyeveryfiveminutesduringtheday.JPSSsatellitescanprovideahigherresolutionmeasurementofaerosolsovertheentireplanetonceaday.JPSScanalsoobservethemovementofaerosolsfromonesideoftheplanettotheother.JPSScanalsomeasurecarbonmonoxidewhichisassociatedwithpoorairqualityresultingfromwildfires. TheimagemosaicontheleftofthesliderbarshowsvisiblesmokefromwildfiresontheWestCoastoftheblowingeastwardacrosstheUnitedStates.Theimagetotherightofthesliderbarshowstheconcentrationsofairborneparticles,oraerosols,fromthefiresthatweresweptwesttoeast.DatafromSuomi-NPPsatellite,whichispartoftheJPSSsystem.Credit:NASAEarthObservatory/SSAI/SuomiNPP