Hay’adda caafimaadka adduunka ee WHO ayaa warbixin ay soo saartay todobaadkii hore ku sheegtay in in ka badan 1 milyan oo qof oo u dhinta cudurrada sambabada, neefta, kansarka sanbabada iyo cudurrada kale ee neef-mareenka in laga hortagi karo sannad kasta adduunka oo dhan haddii dalalku qaadaan tallaabooyin lagu hagaajinayo tayada hawada. Tani waa sahankii ugu horeeyey ee hay'adda caalamiga ah ee baaxadda leh ee wasakhowga hawada dibadda uga yimaadda adduunka oo dhan.
In kasta oo wasakhowga hawada Maraykanku aanu la barbar dhigin kuwa laga helo waddamada sida Iran, India, iyo Pakistan, waxaa jira wax yar oo loo dabaaldego marka la eegayo tirakoobka California.
Sahanku waxa uu ku tiirsan yahay xogta laga soo sheegay dalka dhawrkii sano ee la soo dhaafay, waxana ay cabbirtaa heerarka hawo-mareenada ee ka yar 10 mikromitir - waxa loo yaqaan PM10s - ku dhawaad 1,100 magaalo. WHO waxa ay sidoo kale soo saartay miis ka gaaban isbarbardhigga heerarka xitaa siigada siigada, loo yaqaan PM2.5s.
WHO waxay ku talinaysaa xadka sare ee 20 micrograms per cubic meter PM10s (oo lagu sifeeyay " celceliska sanadlaha ah" ee warbixinta WHO), taasoo keeni karta dhibaatooyin xagga neefsiga oo halis ah bini'aadamka. In ka badan 10 micrograms mitir kuyuubik ee PM2.5s ayaa loo arkaa inay waxyeello u geystaan dadka.
Waxa ugu sarreeya liiska magaalooyinka ugu xun qaranka ee korodhka soo-gaadhista labada qaybood ee walxaha qayb ka ah Bakersfield, oo hesha celceliska sanadlaha ah ee 38ug/m3 PM10s, iyo 22.5ug/m3 PM2.5s. Fresno kama foga, isagoo galay kaalinta 2aad dalka oo dhan, iyadoo Riverside/San Bernardino ay sheegtay kaalinta 3aad ee liiska Mareykanka. Guud ahaan, magaalooyinka California waxay sheegteen 11 ka mid ah 20ka dembiilayaal ee ugu xun labada qaybood, kuwaas oo dhamaantood ka sarreeya heerka badbaadada ee WHO.
"Waan ka hortagi karnaa dhimashadaas," ayay tiri Dr. Maria Neira, oo ah agaasimaha waaxda caafimaadka dadweynaha iyo deegaanka ee WHO, oo xustay maalgelinta heerarka wasakhowga hoose si dhakhso ah ayey u bixiyaan sababtoo ah heerarka cudurrada oo hooseeya iyo, sidaas darteed, kharashka daryeelka caafimaadka oo hooseeya.
Muddo sanado ah, cilmi-baarayaasha adduunku waxay ku xidhidhiyeen heerarka walxaha qayb ka ah kaymaha caafimaadka qaba. Daraasado ay sameeyeen Golaha Cilmi-baarista Deegaanka Dabiiciga ah ee 2007 waxay soo jeedinayaan in dhimista PM10 ee 7%-20% la gaari karo haddii tiro badan oo geedo ah la beero, taas oo ku xidhan helitaanka meelaha beerashada ku habboon. Dalka Maraykanka, Xarunta Cilmi-baadhista Kaymaha Magaalada ayaa daabacday warqad sannadkii 2006-dii oo lagu xusay in Sacramento lix milyan oo geed ay shaandhayso 748 tan oo PM10 sannadkii.