In 2020, EPA projects a reduction of 1.1 million tons per year of ozone precursors due to the new standard. In addition, the reduction of NOx emissions will also result in a reduction of secondary nitrate particulate matter, which forms in atmosphere when NOx combines with ammonia, of about 43,000 tons per year. EPA also proposed the above standard for gasoline-fueled engines, but is not finalizing the standard at this time. The Agency is planning a supplemental rulemaking to address gasoline-fueled engines specifically. Nitrogen oxides from diesel engines are a major contributor to the formation of ground-level ozone and particulate matter.
Ozone reduces lung function and aggravates existing respiratory problems such as asthma.
It can also cause a breakdown in a person's ability to fight off infectious bacteria. Particulates become lodged in the lungs' most sensitive tissue and may result in premature death. In addition, ozone, particulate matter and nitrogen oxides cause crop damage, acid rain, and reduction in visibility. The near term increase represents a 2 to 4 percent increase in engine price and less than 1 percent of the price of most new heavy duty vehicles. EPA does not expect any increase in fuel consumption due to the new rule.