Michael Hart, weyi ɛwɛ San Diego yɔ, pakpa-ɩ nɛ pakʋyɩ ɛ-yɔɔ se ɛɖɔma Etaazuunii komina paɣtʋ ndʋ tɩ-taa pɔtɔm se paɖɩzɩ helim taa wondu lɩɣ yɔ. Pɩfɛyɩ ɖeu se ɛyʋ ɛkpaɣ nɛ ɛsʋʋ ɛjaɖɛ nɖɩ ɖɩ-taa mbʋ payaɣ se hydrofluorocarbons (HFC) yɔ, ye ɛfɛyɩnɩ takayaɣ ŋga kalɩzɩ-ɩ nɛ ɛha-ɩ yɔ.