Stronger limits proposed to control deadly soot pollution in the US

The Environmental Protection Agency says the U.S. needs to implement tougher standards to control soot pollution in the air, which can kill thousands of people a year when inhaled.

Environmental and public health groups that have been pushing for a stronger standard were disappointed, saying the EPA proposal does not go far enough to limit emissions of what is broadly called "fine particulate matter," the tiny bits of soot we breathe in unseen from tailpipes, wildfires, factory and power plant smokestacks and other sources.

In a development that could lead to an even lower standard, the EPA said Friday it also would take comments on a range of ideas submitted by a scientific advisory committee, including a proposal that would lower the maximum standard for soot to 8 micrograms. A microgram is one-millionth of a gram.