IsAlahwe

IsAlahwe liyinhlwa yevanga enophawu u -Ar nenani lobuchwe eliyi-18. Liseqenjini le-18 lecansi lezinhlwa futhi liwuhowo lwekhethelo. IsAlahwe liwuhowo lwesithathu oliyinala kakhulu kumoyambulunga woMhlaba, ngenani elingu-0.934% (9340 ppmv ). Liyinala ngokuphindwe kabili kunomhwamuko wamanzi (olinganiselwa ku-4000 ppmv, kodwa uhluka kakhulu), ligcwele izikhathi eziphindwe ngama-23 kunomcalahle ontuhlambili (400 ppmv), futhi luyinala izikhathi ezingaphezu kwama-500 kunenkanyihwe (18 ppmv). IsAlahwe liwuhowo lwekhethelo oliyinala kakhulu egobohleni lomhlaba, lwakha okungaba -0.00015% lwegobohla.