what in the world is a ppm?

We live in a capitalist society and we around surrounded by numbers. We count the money in our wallet, we count the money in our bank account, the interest rates of our credit cards and we count the days till we have less money in our wallet when the rent is due. Numbers are surrounding us from all sides and we live and breathe numbers. But one wonders how much do we really understand numbers. Joel Best in his article "More Damned Lies and Statistics. How Numbers Confuse Public Issues" says that we barely understand numbers at all. He states that not only are we constantly lied to with numbers but that the people who use these numbers to lie to us don't understand numbers all that well either. When looking at the crisis that surrounds us we see that we are constantly bombarded with risk calculations, and means and averages, percentages and parts per million (ppm). What in the world is a part per million and how am I supposed to understand that our atmosphere needs to reduce carbon in the atmosphere to 350 ppm? We are given these numbers but we don't understand what they mean. If 350 ppm is the number we need then what does smoking one cigarette do? Does a single cigarette put into the atmosphere 1 ppm, .01 ppm, .00000000000000000000000000000000000000001 ppm, or nothing at all. The entire environmentalism movement has been based on numbers but there has been no clue as to what that means to us. It is strange that although it seems very intuitive to us to use numbers for all of our issues, it is actually counterintuitive for many of our causes. As Best puts it, if a study indicates that diet cola drinkers are 20 percent more likely to have a specific medical condition. People may take that to mean the 20 percent of diet cola drinkers will get this disease. But in actuality if only 5 people out of 10000 have the disease than that would mean that a 20 percent increase in diet cola drinkers would mean that 6 out of 10000 diet cola drinkers would have the disease. 20 percent greater in this case means an additional 1 person out of 10000 and that in the overall scheme of things is almost insignificant. So it becomes increasingly clear that these numbers aren't telling us a thing so then why is it that we rely on them so much? Perhaps what we really need to be doing is moving away from numbers and actually showing people information in a more human way. We weren't born with money in our pockets and we aren't capitalists at 1 year old, so in our hearts we aren't made to understand numbers. Telling me that x number of smokers contract lung cancer does not affect me as much as showing me a smokers lung.