Emission Control and Air Pollution Module

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Partnership Illinois

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Frequently Asked Questions

About Test Notices

Q. When can I come in for an emissions test?

A. We urge you to have your vehicle tested as soon as possible after receiving the test notice. A vehicle can also be tested up to a month early. Bring your test notice with you when you come for the test.

Q. Do I have to keep the test notice after my car has been tested?

A. You may discard your test notice after your vehicle has passed the emissions test or received a waiver for this test cycle.

Q. After my vehicle has been tested, do I need to mail anything to the Illinois Environmental Protection Agency (EPA) or the Secretary of State?

A. No, since test results are automatically recorded and transmitted. If your drivers license, license plates or both have been suspended for failure to comply with the vehicle emissions test, it will take approximately 72 hours for the suspension to clear after you pass the test or receive a waiver. Verification that the suspension has been terminated can be obtained by calling the Secretary of State's office at 1-800-252-8980. Please have your drivers license number and vehicle identification number (VIN) ready when you call.

About Test Procedures

Q. What is the Illinois EPA testing for?

A. Cars are tested for the pollutants called hydrocarbons and carbon monoxide. Hydrocarbons are unburned gasoline particles that contribute to the formation of ground-level ozone often referred to as smog. Carbon monoxide is a colorless, odorless and toxic gas formed from partially burned fuel that can adversely affect mental function, visual acuity and alertness.

Q. Why do all of the accessories need to be turned off?

A. Electrical accessories can interfere with the electronic sensing of engine speed and can adversely affect the test results.

Q. Why aren't diesels tested?

A. Diesel exhaust contains relatively low levels of hydrocarbons and carbon monoxide, which are the pollutants tested for in Illinois.

Q. How much will it cost to have my vehicle tested?

A. The state of Illinois does not require the general public to pay a fee for an emission test or the issuance of a waiver.

Q. Why don't all vehicles have to be tested?

A. Based on national air quality standards, only the Chicago and East St. Louis areas of the state have severe ozone problems that necessitate emissions testing.

About Test Results

Q. What should I do if my car fails the emissions test?

A. First, see the state inspector, located at each test station, for an explanation of your test results. The state inspector will also be able to provide you information on what repairs typically are necessary to remedy your vehicle's problems.

Q. What happens if I do not comply with the vehicle emissions test?

A. Your drivers license, license plates or both will be suspended.

Q. How should I choose a repair shop?

A. We recommend that you seek a technician who is trained and experienced in emission system diagnosis and repair. Many technicians are certified by the vehicle manufacturer, and the National Institute for Automotive Service Excellence. Seek a shop with a four-gas-emissions analyzer that is regularly calibrated. The shop should be willing to guarantee work and have a refund policy.


-Back to Day 5a Lesson-


Gasoline-powered engines produce emissions that form ground-level ozone (smog), a respiratory irritant that can be harmful to humans. Ozone can cause eye and throat irritations and can damage breathing passages, making it difficult for the lungs to work. This pollutant is prevalent in major metropolitan regions, including Chicago and East St. Louis.

As Illinois struggled during the late 1970s and the early 1980s to come to terms with ozone problems, it became evident that federal and state ozone health requirements could not be attained without implementing some type of vehicle emission testing program. In 1983, the U.S.

Environmental Protection Agency (EPA) began formal sanctions to withhold federal highway funding from Illinois for failure to institute such a program. In response to these sanctions, the Illinois EPA Vehicle Emissions Testing Program was initiated.

Since the program started in 1986, vehicles have become less polluting, but still contribute as much as 50 percent of the emissions that form ozone in urban areas. As more vehicles are now equipped with an array of computer-controlled components that reduce pollution, enhancements to vehicle emissions tests will be necessary to effectively identify excessive emissions.

Ozone is formed near the ground, ozone is formed in a three-step process:

1. Gasoline, paints and solvents evaporate, releasing reactive organic compounds.

2. Cars and factories burn fossil fuels, releasing nitrogen oxide gases.

3. Heat and sunlight trigger a chemical reaction between these emissions, transforming them into ozone.