In the meantime, however, China is struggling to meet its set environmental targets, including reducing sulphur dioxide and nitrogen oxide emissions.

FORBES: Ending China Pollution An Uphill Battle

Cheap gas and environmental legislation under the Clean Air Act, aimed at emissions of sulphur dioxide, nitrous oxide and mercury (but not carbon dioxide) from dirty coal plants, accelerated a trend that is set to continue.

ECONOMIST: America��s bounty: Gas works | The

The new rule required about half the states to reduce their emissions of sulphur dioxide, nitrogen oxide and other emissions based on projections of how many pollutants were crossing state lines, and told them how to do it.

ECONOMIST: Air pollution

Six greenhouse gases are reported on: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulphur hexafluoride.

BBC: NI greenhouse gas emissions fall