"[a] child born in America today will grow up exposed to more chemicals than a child from any other generation in our history. A 2005 study found 287 different chemicals in the cord blood of 10 newborn babies - chemicals from pesticides, fast food packaging, coal and gasoline emissions, and trash incineration. They were found in children in their most vulnerable stage. Our kids are getting steady infusions of industrial chemicals before we even give them solid food. Now, some chemicals may be risk-free at the levels we are seeing. I repeat: some chemical may be risk-free. But as more and more chemicals are found in our bodies and the environment, the public is understandably anxious and confused. Many are turning to government for assurance that chemicals have been assessed using the best available science, and that unacceptable risks haven't been ignored."
Pollution levels 100 - 200 years ago were much greater than now.
Early 1800s - Town gas from coal drips tar into the rivers. Vulcanized rubber plants discharge noxious chemicals directly into the streams. Coal smoke chokes the air in big cities. Chemical factories operate without thought to people downwind.
Mid 1800s - Living conditions in urban areas horrify reform minded commissions in London in the 1840s and America in the 1850s and 60s. Progress is slow but the common interest in pure drinking water and sanitation is spurred by epidemics of typhoid and cholera. Smog episodes begin killing residents of large cities like London.
1940 - 1950 - Deadly smog episodes in Donora Penn. (1948), London (1952, 1956), New York (1953), and Los Angeles (1954).
Here's smoky Pittsburgh from 1940.
I mean look at the current big to-do about Mercury from US powerplants.
“Mercury emitted from coal-fired power plants comes from mercury in coal, which is released when the coal is burned. While coal-fired power plants are the largest remaining source of human-generated mercury emissions in the United States, they contribute very little to the global mercury pool. Recent estimates of annual total global mercury emissions from all sources — both natural and human-generated — range from roughly 4,400 to 7,500 tons per year. Human-caused U.S. mercury emissions are estimated to account for roughly 3 percent of the global total, and U.S. coal-fired power plants are estimated to account for only about 1 percent.”
“Natural sources of mercury—such as volcanic eruptions and emissions from the ocean—have been estimated to contribute about a third of current worldwide mercury air emissions, whereas anthropogenic (human-caused) emissions account for the remaining two-thirds. These estimates are highly uncertain. Land, water, and other surfaces can repeatedly re-emit mercury into the atmosphere after its initial release into the environment.”