There is a scientific principle that says in effect that there is no free lunch. By that, I mean to say that if you want matter or energy, you must get it from something rather that simply creating it out of nothing. This is why there can never be perpetual motion, because the term implies that motion is possible without using anything as a source. However, it seems that some college students are being taught that all scientific principles can be ignored when trying to scare the public.
I listened with amusement when a young medical student was telling his audience how two-cycle engines, like the ones on weed blowers, produce more contaminants than automobile engines. Allthough there is a basis for his beliefs, it is absolutely impossible to produce anything from nothing, and that includes polution. Apparently, either he, or probably one of his college professors, had heard, or read, that a two-cycle engine does not burn as clean as a four-cycle engine. True! But that is a measure of the percentage of the contaminants rather than total production. To say that an engine burning about a pint of fuel an hour will produce more pollution than one burning over twelve times as much fuel, would require the smaller engine to be making pollution out of nothing in order to compete in the amount of pollution produced. Add that to the fact that there are nearly a thousand times more four cycle car engines in use than there are two cycle mower and blower engines, and you begin to see the horse puckey in his line of thinking. It's almost as bad as saying that wooden matches cause more smoke than forest fires!
Pollution is a very broad term, and is often confused with irritants. A good example of this is that people will notice and recoil from wood and diesel smoke, while paying no attention to the thousands of automobiles passing them each day. Though wood smoke is an irritant, and does contain some pollutants, it does have some redeeming qualities. The smoke from burning organic matter contains ashes that are microscopic burnt-out skeletons of the molecules that the matter was composed of. They look like tiny little geodeasic domes that are hollow inside and are called "Bucky Balls". They are what composes the major part of visual smoke emitted from burning organic matter. These little frameworks of molecules are very effective in absorbing the tiny droplets of oil that are released in the air from burning hydrocarbons. The lye that is contained in the wood-smoke tends to desolve the tiny oil droplets so the oil actually enters the interior of the Bucky Ball. Thus, captured and contained, the oil laden balls settle to the ground where there are consumed by bacteria.
So even though the lye in woodsmoke may irritate your eyes, it saves your lungs from the little oil droplets and helps to desolve and thereby help you to eliminate the hydrocarbon oils already in your system.
Now a word about diesel smoke. As you know, the smoke from diesel engines can be very odiferous, and makes people think it is a bad pollutant. Though it may smell worse than the fumes from a gasoline powered vehicle, there is no comparison when we speak of dangerous pollutants. I have operated heavy diesel powered equipment inside deep excavations when the air was still and a number of machines were belching huge amounts of diesel smoke. This is no problem except for the irritation. But in these conditions, everyone is careful not to let any gasoline powered vehicle, even the foreman's half ton pickup truck, enter the excavation. To do so, would release fumes that could injure, and possibly kill, the people in the pit.
Some time back, a fellow decided to end it all by starting his car engine in a closed garage after running a garden hose from the tail pipe through the car window. Even a few moment of this will result in permanent brain damage and death takes a surprisingly short exposure to the carbon monoxide fumes. The fellow leaned back and waited for what he condsidered to be a short wait. After several minutes, he emerged from the garage, choking and gagging. He had failed to consider that his car was a Mercedes, diesel.
