Nkwekọrịta Air Quality nke United States na Canada
Nkwekọrịta Air Quality bụ nkwekọrịta gburugburu ébé obibi n'etiti Canada na United States.  Praịm Minista Canada bụ Brian Mulroney na Ónyé isi ala America bụ George H. W. Bush bịanyere áká na ya na 13 Machị 1991 wee banyé n'ọrụ ozugbo.  A na-akpọkarị ya n'ogè mkparịta ụka ya dị ka "Nkwekọrịta Mmiri Acid", ọkachasị na Canada.  Mkparịta ụka malitere na 1986 mgbè Mulroney na ónyé isi ala Reagan kwurịtara okwu ahụ.  Mulroney kwusiri okwu ahụ ike ugboro ugboro na nzukọ ihu ọha ya na Reagan n'afọ 1987 na 1988

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