When the engine is cold or when it is misfiring.
gas from a car
a lot
Mileage doesn't matter. As long as it is maintained properly and the check engine light isn't on it will pass emissions.
Planes.
Most of them use gasoline as well, which would cause pollution. Even if it is completely electric, that energy had to come from somewhere, Like a power plant that produces pollution to create electricity. If you run on only electric, and get your energy from a windmill or waterwheel then it wouldn't!
An 18-wheeler truck typically emits significantly more pollution than a car. This is due to the larger engine size and heavier weight of the truck. On average, an 18-wheeler can emit between 4 to 8 times more pollution than a car, depending on the specific models and driving conditions.
Pollution of the atmosphere comes from many sources and most of them are caused by man- car emissions, smoke from factories, and by-products of manufacturing.
It checks how much pollution in puts out
because CNG does not cause of any pollution and does not emit carbon.
No, nuclear power maintains environment non pollution as it does emit green house gases and do not contribute to global warming and environment pollution.
Yes, a a battery will emit the fumes from the Sulfuric acid which is extremely toxic.
Cars emit the most pollutants when accelerating. If the lights are synchronized to allow the heaviest flow of traffic to move without stopping and starting the need for acceleration is minimized and pollution reduced. An added benefit is that, since cars also emit more pollution when idling, unless they turn off their engines, allowing more cars to travel in their most efficient engine speed range is enhanced by light sychronization.