Acid rain: Problem unsolved

The Canadian Acid Deposition Science Assessment 2004 is available online and paints a sad picture of the problem, noting that between 21 and 75% of eastern Canada "receive levels of acid deposition in excess of critical loads (i.e. the amount of acid deposition that a particular region can receive without being adversely affected) (...) In Canada and the U.S., major sources of acid-causing emissions are electric power generation, non-ferrous mining and smelting, upstream oil and gas operations and transportation." [Source: Executive Summary]