Starting Jan. 1, 2011, farmers will see changes in new diesel-powered farm equipment. The U.S. Environmental Protection Agency (EPA) has mandated new diesel engine exhaust emission standards in its Clean Air Non-road Diesel Rules. These new emission standards will impact only new equipment.

“The EPA has adopted a multi-tiered, comprehensive national exhaust emission standards program designed to reduce emissions from non-road diesel engines,” says John Nowatzki, North Dakota State University Extension agricultural machine systems specialist. “Previous stages of the Clean Air Non-road Diesel Rules primarily affected over-the-road diesel-powered equipment.”

Called the Tier 4 rule, the standards include non-road diesel engines of 175 horsepower or larger in 2011 and 75 to 175 horsepower in 2012. The Tier 4 rule is intended to reduce diesel engine emissions with fuel control and exhaust system modifications. To meet these new standards, diesel engine manufacturers have developed new engine emission control systems. Planned future stages of this EPA standard will affect all non-road diesel engines.

“The goal of the Tier 4 rule is to significantly reduce nitrous oxides and particulate matter in the exhaust of non-road diesel engines,” Nowatzki says. “Nitrous oxide exhausted from diesel engines becomes a greenhouse gas in the atmosphere that affects the temperature of the Earth. Particulate matter in a diesel engine exhaust appears as soot, which is a harmful air pollutant linked with eye, nose and throat irritation and breathing problems.”

When the Tier 4 rule is implemented by 2015, the EPA mandates will have cut both nitrous oxide and particulate matter in diesel exhaust by 90 percent.