Although not covered by the rules, sulfur dioxide also could drop up to 90 percent because it would be filtered out by the same technology that controls hydrochloric acid.
The Mount Pintaubo eruption in 1991 released more than 20 million tons of sulfur dioxide into the atmosphere, causing a drop in temperature by half a degree Celsius for about two years.
1991年皮纳图火山爆发时释放了超过20亿多吨的二氧化硫进入大气，致使两年左右气温下降了1度半。
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"We make very clean, sulfur-free hydrocarbons that drop directly into the existing infrastructure for the production of diesel fuel," said William J. Sims, the chief executive of Joule.