Canada, U.S. fight acid rain.
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D015258:Acid Rain / Q000331:legislation & jurisprudence / Q000517:prevention & control* / Q000633:toxicity; D000393:Air Pollutants / Q000633:toxicity; D000397:Air Pollution / Q000331:legislation & jurisprudence / Q000517:prevention & control*; D002170:Canada; D004784:Environmental Monitoring / Q000331:legislation & jurisprudence*; D006801:Humans; D007391:International Cooperation; D008452:Maximum Allowable Concentration; D009609:Nitrous Oxide / Q000592:standards / Q000633:toxicity; D011210:Power Plants / Q000592:standards*; D013458:Sulfur Dioxide / Q000592:standards / Q000633:toxicity; D014481:United States
D015258:Acid Rain; D000393:Air Pollutants; D013458:Sulfur Dioxide; D009609:Nitrous Oxide