The Clean Air Act of 1990 is a federal law designed to control air pollution on a national level. From this law, sources of pollution, like ozone, CO2 and fine particulates, are regulated by the Environmental Protection Agency (EPA) to control the volume and types of these emissions.

The EPA identified diesel engines as a source of air pollution. Diesel engines produce Particulate Matter and Nitrogen Oxide. Particulate Matter (PM) is mostly unburned hydrocarbons like soot and has been classified by several government agencies as either a ‘human carcinogen’ or a ‘probable human carcinogen’. It is also known to increase the risk of heart and respiratory diseases. Nitrogen Oxide (NOx) is known to cause smog and acid rain.

Prior to 1996 diesel engines used in farm, construction and agricultural tractors had no modern emissions controls and produced a lot of harmful byproducts. Beginning in 1996 the EPA introduced the ‘Tier’ emissions standard with a series of target dates to achieve progressively cleaner and healthier engines.

Tier 1 emissions standards, instituted by the EPA in 1996, required new diesel engines to regulate emissions through the use of technology like computerized fuel injection systems and particulate filters.

Over the next 15 years diesel engine emissions became progressively cleaner as they moved from Tier 2 in 2001 to Tier 3 in 2008 to Tier 4 in 2014. New Tier 4 engines dropped both their PM and NOx by over 90% from Tier 1 compliant engines. Today’s new Tier 4 diesel engines produce almost zero harmful emissions and are much cleaner and healthier of both humans and the environment.

It is hard to put a value on clean, healthy air. Over the past five years Elements has committed itself to reducing the Particulate Matter and NOx that our fleet emits by replacing many of our Tier 1 and 2 tractors with cleaner, healthier Tier 3 and Tier 4 tractors. Introducing these new tractors is expensive though, as each new Tier 4 tractor costs about $120,000.


Tier 4 Clean Diesel Technology
Diesel Health & Exhaust Overview
Diesel Particulate Matter Health Impacts