Mobile Sources include a variety of vehicles, engines, and equipment that generate air pollution, and that move or can be moved from place to place. There are two categories of mobile sources: on-road vehicles and nonroad vehicles.​​

​​On-road ​vehicles include:

• Light-duty vehicles
  
• Light-duty trucks
• Heavy-duty vehicles
• Medium-duty passenger vehicles
• Motorcycles 

Nonroad ​vehicles include off-road gasoline, diesel, and equipment vehicles such as:

• Aircraft
• Airport service equipment and vehicles
• Commercial equipment
• Construction equipment and vehicles
• Farm equipment
• Industrial equipment
• Lawn and garden equipment
• Locomotives
• Logging equipment
• Marine vessels
• Railway maintenance equipment
• Recreational engines and vehicles
  
• Recreational marine vessels​