They promise lower emissions of nitrogen oxides, sulfur oxides, particulate matter, and carbon dioxide (CO2).
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Nitrogen oxides contribute to haze and form small particles that make people sick and even kill them.
According to the company it removes not just sulfur dioxide, but also carbon dioxide and nitrogen oxides.
"The marble and sandstone were being weathered by atmospheric fumes, including sulfur dioxide and nitrogen oxides, " Gopalakrashne says.
These gases are then used to clean up smog-producing nitrogen oxides, or NOx.
These include the exhaust gases such as nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOCs), and carbon monoxide (CO).
The proposal set one target for reducing nitrogen oxides from all power plants.
That dominance is threatened by tightening emissions regulations governing nitrogen oxides and particulate matter--emissions that plague diesel engines in particular.
All over the world, since the mid-20th Century, sediments have become measurably enriched in 'reactive' nitrogen - nitrogen oxides and ammonium compounds.
Most experts warn against ozone, which results from the sun heating hydrocarbons and nitrogen oxides in vehicle and industrial emissions.
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Automakers already strip lots of other pollutants from cars, such as the nitrogen oxides that contribute to smog, and carbon monoxide, which is poisonous.
The Environmental Protection Agency (EPA) estimates idling trucks consume nearly one gallon of fuel per hour, while emitting nitrogen oxides and particulates, which contribute to smog.
Nitrogen is separated from oxygen before combustion, thereby reducing the volume of exhaust gas and making the exhaust easier to treat by preventing the formation of polluting nitrogen oxides.
With engines switched off, approximately 1, 000 pounds of nitrogen oxides emissions, 165 pounds of sulfur oxides, and 30 pounds of particulate matter are eliminated in a 24-hour port call.
Also, to comply with prevailing U.S. emissions standards on nitrogen oxides, or NOx, these big diesels require fairly complicated systems of postcombustion treatment with a water-based urea solution, called AdBlue.
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The new rules will require automakers to roll out passenger cars and trucks that will reduce smog-producing pollutants such as nitrogen oxides by 75 percent less from the 2014 levels.
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Based upon 2005 emissions, power plants must cut sulfur dioxide emissions 73% (from 8.8 million tons per year to 2.4 million), and nitrogen oxides 54% (from 2.6 million to 1.2 million).
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Professor Kyrtatos believes ships' engines could be adapted to meet impending legislation which, he predicted, would require emissions of nitrogen oxides from ship exhausts to be cut by 30% by the year 2007.
China is particularly struggling to curb what are known as secondary pollutants, formed when primary pollutants such as emitted sulfur dioxide and nitrogen oxides, from coal burning and other sources undergo reactions in the atmosphere.
In Europe the trucking industry has settled on a technology called selective catalytic reduction, in which urea is periodically injected into the exhaust system to break down the NOx, converting nitrogen oxides into (somewhat) harmless ammonia.
More stringent engine standards were already set to take effect three years hence, and the EPA was now requiring at least a 90% reduction in the amount of nitrogen oxides and soot emanating from diesel engines.
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The researchers examined the prevailing inspection system called On-Board Diagnostics II (OBD-II), which tests for excessive carbon monoxide, hydrocarbons, and nitrogen oxides, and also checks the power-train systems for problems that might eventually lead to elevated emissions levels.
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The EPA engineers came up with a formula that automakers around the world have long been groping for--an engine that explodes fuel at such a relatively low temperature (below 2, 000 degrees Fahrenheit) that almost no noxious nitrogen oxides are produced.
If we believe environmental activist claims that carbon monoxide, nitrogen oxides, sulfur dioxide, mercury, and particulate emissions to say nothing of global warming and carbon dioxide emissions are so bad for human health, natural gas production should be a no-brainer.
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The report also says that the congestion charge has caused reductions in the two most concerning pollutants to London, by 8% for nitrogen oxides and 7% for particulate matter that is fine enough to penetrate the lungs and cause health problems (referred to as PM10).
The combined effect of charging and improved vehicle technology, notably cleaner-burning diesel engines that are being used in more buses and taxis, has led to an overall reduction of 13% in nitrogen oxides and 12% in PM10 via vehicle tailpipe emissions in the charging zone.
That means shipowners who wish to ply these waters will have to stop using bunker fuel (the cheap stuff left over once petrol, diesel and aviation fuel have been distilled from crude oil) to power their vessels because burning it produces too much sulphur dioxide, nitrogen oxides and soot.
Natural gas power emits merely 20% of the carbon monoxide of coal power, 20% of the nitrogen oxides of coal power, less than 1% of the sulfur dioxide of coal power, less than 1% of the particulate matter of coal power and less than 1% of the mercury of coal power.
It must implement regulations that capture the environmental benefits of nuclear, such as low emissions of carbon dioxide as well as nitrogen and sulfur oxides.
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Future versions, they believe, should also be able to cope with pollutants that do not contain carbon, such as oxides of nitrogen.
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