Los Angeles has a smog problem. In L.A. we love our cars. Gasoline and air go in one end and several different gases (and other stuff) come out the other. There are the innocuous products of H2O and CO2. (More on my thoughts on CO2 in a future post.) Then there are the immediately harmful products: CO, NOx, VOCs, particulates, hydrocarbons and others.
Volatile Organic Compounds (VOCs) react with nitrous oxides (NOx) to form ozone which leads to smog. We’ve been measuring the smog since at least 1976. The following graph (from the Air Quality Management District) shows two variables over time.
The bar graph shows how many days we exceeded Federal Health Standard levels. In other words, how many days the 8 hour average was greater than 75 ppb (parts per billion). This is the least interesting variable. A day with 76 ppb is counted the same as a day with 300 ppb. So two similar bars could have huge differences in the actual amount of smog.
The connected dots show an average maximum over 8 hours. This seems much more informative. It goes from a high of 321 ppb in 1978 to a low of 123 ppb in 2010 a decrease of 62%. This is a pretty dramatic decline especially considering the vehicle miles traveled (nationwide) increased by 171% between 1970 and 2004. (See long boring pdf.)
So what is my point?
On Topic Rant
The original article I read said:
Peak levels of ozone were 143 parts per billion in 2010, only marginally down from 710 ppb in 1966.
Going from 710 ppb to 143 ppb is NOT a marginal decrease. It is a decrease of 80%! And considering there are almost 3 times the miles being driven, this is an amazing accomplishment. I was really surprised to see this statement in the New Scientist.
This is another reason why students and citizens need to understand math and algebra: So they can apply critical thinking to news reports and not just accept what someone, who may have an agenda, says. (One of the sources for this article was the Air Quality Management District. The AQMD might have an incentive to emphasize that smog is still a problem, which it is. It is just a smaller problem.)
Off Topic Rant
Right now there is a feeling among many voters that “government programs are evil and must be abolished.” Some government programs probably are. But they need to be evaluated independently, instead of voting no, no, no on every proposal that comes along. We should look at some objective, measurable criteria and ask, is this good for society.
It is a pain in the @** to get a smog check. It is even worse when I have to get repairs. But the laws and the bureaucracies (the AQMD and DMV) that enforce them have reduced smog by 80% in 44 years. This has saved lives and improved the health and quality of life for millions of people.
Rant over… I really should be getting ready for school.