The goals going forward, the mayor continues, are not just to reduce greenhouse gas emissions but also those tied to acid rain, soot and mercury.

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For example, our New Jersey coal plants with their various pollution-control systems have been able to reduce, by over 90 percent, emissions of mercury, acid gases and soot.

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Others, such as American Electric Power and Southern Company, have helped fund the legal battles to overturn current rules and regulations affecting mercury, soot, acid rain and greenhouse gases.

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Working with his students, Butz twice soaked the samples in a weak solution of hydrochloric acid to remove any contemporary soot stains.

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They found that the older soot samples contained vanillic acid, an indicator of burning conifer trees.

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The sulfur dioxide and soot thrown off results not only in a polluted atmosphere but also acid rain that falls on a third of China's cities.

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