It is impossible to ignore the presence of air pollution when it from obvious sources such as smoke from fires or smog from vehicle pollution. Polluted air can also be invisible and with impact to billions of people. The air we breathe can contain toxins from car traffic, coal-fired plants and oil refineries.
A recent article by Carl Zimmer, a columnist for the New York Times discusses the effect this pollution has on current society but also human evolution.
Over ninety percent of the world lives in areas where fine particulate matter (PM), exceeds the World Health Organization's (WHO) guideline for healthy air and contribute, along with tobacco use, to nearly 20 million deaths each year. These airborne toxins not only contribute to cases of lung cancer and heart disease, we are now finding connections to diseases such as diabetes and Alzheimer’s.
Scientists are still figuring out how air pollution causes these ailments. They are also puzzling over the apparent resilience that some people have to this modern onslaught. Some researchers now argue that the answers to these questions lie in our distant evolutionary past, millions of years before the first cigarette was lit and the first car hit the road.