As used in this chapter, the following terms shall have the meanings indicated:
A self-propelled vehicle designed primarily for transporting persons or property on a public street or highway which is propelled by a compression-ignition-type of internal combustion engine; for purposes of this chapter, passenger automobiles and motorcycles are excluded.
Substances emitted into the atmosphere from any opening downstream from the exhaust ports of a motor vehicle engine.
Includes corporations, companies, associations, societies, firms, partnerships and joint-stock companies, as well as individuals, and shall also include all political subdivisions of this state or any agencies or instrumentalities thereof.
Small gasborne and airborne particles, exclusive of water vapor, arising from a process of combustion in sufficient number to be observable.