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If we limit the amount of useage of either cargo trucks or passenger cars, which of these two would most decrease the amount of air pollution produced?
Question Date: 1999-01-25
Answer 1:

In Guadelupe, the air pollution is not the same as in Los Angeles. The air pollution in your town is mostly caused by dust and dirt from the farm fields. Limiting cars or trucks would do little to help. Changing how fields are plowed can help. One thing that can be done is to spray water on the field to keep the amount of dust down.

Answer 2:

Your question is interesting.Like most science problems, it has a big math component. We need to know two things, how many cars (vs. trucks) are there, and how much does each pollute. I don't know the answer to part 1, but you could either ask a local DMV office or do your own count. As you probably know, vehicles in California have to pass smog tests (more on this at the following web site: http://www.smogcheck.ca.gov/MOVING.HTM). This helps provide the information for part 2. Check out http://www.smogcheck.ca.gov/asm1198.htm. They have values for average emissions for different weight vehicles. If we look at one type of polution, hydrocarbons (unburned fuel that goes out the tailpipe), and we look at vehicles made in 1993 or later, We see that, on average, trucks put out twice as much as cars. So what percent of the vehicles on the road would have to be trucks before getting rid of trucks would help more than getting rid of cars?

Notice that I made some assumptions in deciding which numbers to use. What if cars were usually newer than trucks? What if I were more interested in lowering CO emissions?

For an overview of car pollution problems and some solutions, see

Thanks for asking.

Answer 3:

Vehicles which burn gas produce one type of pollutant and vehicles which burn diesel produce another type of pollutant. Please read about gas burning vehicle pollution in earlier questions. Both are not good.

Diesel is a more efficient fuel source, which means that per amount of diesel pumped into a diesel engine more of it burns than the same amount of gas. The way a combustion engine works is by pumping in some combustible fuel (gas or diesel), burning the fuel, the energy released from the burning of the fuel is used to move the engine's pistons up and down, which makes the wheels of the vehicle go round and round (ha ha). So if you can burn all of the fuel you pump into an engine you would be at 100% efficiency. However, this does not happen. So diesel engines are more efficient which is always better for the environment, but the product of combustion of diesel is a black particulate matter that is harmful to the environment and not good for humans and other organisms. This is the black exhaust you see pouring out of school buses and large trucks. So it's a trade off; cars that burn gas as their fuel aren't nearly as efficient as diesel vehicles, but both put out bad pollutants--one is invisible and the other is visible.

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