Whether diesel- or gasoline-powered, all combustion engines expel noxious gasses such as unburned hydrocarbons and particulates into the air: the by-products of burned fuel that are discharged from the exhaust pipe into the atmosphere.
In the 1960s, government regulations were instituted to control automotive emissions and reduce the levels of pollution in the atmosphere. Over the years, engineering developments such as the three-way catalytic converter and computer-controlled
electronic fuel injection have reduced automotive emissions today to less than five percent of what they were 40 years ago. Even now, the Environmental Protection Agency (EPA, www.epa.gov) continues to tighten air quality standards as technology improves. By 2009, all passenger vehicles will conform to standards that allow for less than one percent of the tailpipe emissions that were allowed in the 1960s. The EPA's newest standards are called Tier 2. California has separate emission standards for cars and trucks, known as LEV-II. For 2008, seven other states have adopted the California emissions standards: New York, Maine, Massachusetts, Pennsylvania, Rhode Island, Connecticut and Vermont. States that border these states may also sell California-certified vehicles.
Visit almost any new-vehicle showroom and you may hear quite a bit about so-called low-emission vehicles (LEVs). An LEV produces fewer emissions than the average vehicle on the road. This would have been a simple explanation just five years ago, but increased regulations and new powerplant technologies have led to the creation of several new categories of low-emission vehicles that have increasingly stringent standards. California, long the nationwide leader in toughening emission standards, created the CAL LEV (California Low-Emission Vehicle) program and established specific standards. As more states followed California's lead, the following definitions have gradually become accepted across the nation:...
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