title: Acid rain. Demands for action multiply.
mesh_terms: D000397:Air Pollution / Q000517:prevention & control*; D002170:Canada; D007878:Legislation as Topic; D009609:Nitrous Oxide; D013458:Sulfur Dioxide; D014481:United States
chemical_list: D013458:Sulfur Dioxide; D009609:Nitrous Oxide