Shasta Nissan Subaru in Redding, Calif., was fined $34,750 by the California Air Resources Board last week for illegally modifying engines from 2004 through 2007 on their light- and medium-duty vehicles with an aftermarket part before they were sold.

The part, the Vortex Fuel Maximizer, is intended to improve gas mileage and performance in cars by changing the flow of air as it mixes with the gasoline before combustion.

It is illegal in the state of California to perform modifications on a new car before it is sold without first getting ARB approval. Modifying car engines can increase harmful emissions and may lead to the vehicle failing California's smog test.

"ARB's work over the years to ensure that clean burning cars are sold in California has helped us reduce smog levels throughout the state," said ARB Chairman Mary Nichols. "We always require dealers to consult with us before adding aftermarket parts that can increase emissions."

Per the terms of the settlement, Shasta Nissan Subaru will pay a total of $34,750 to the California Air Pollution Control Fund which provides funding to research and programs intended to reduce California's carbon footprint. $17,375 was paid at the time of the settlement, and the remaining $17,375 is due 90 days later.

California's air quality measures are in place to prevent excessive emissions of materials that can be harmful to residents' health. Ozone, also known as urban smog, can affect human health in many ways including: itchy, watery eyes, scratchy throat, difficulty breathing, shortness of breath, coughs, heightened asthma rates, cardiopulmonary cases and premature deaths.