The other deadly, invisible health threat lurking in U.S. cities

For anyone with respiratory problems like asthma or chronic obstructive pulmonary disease (COPD), hot weather and air pollution can make breathing difficult. And according to a new U.S. study, even “safe” levels of hot, polluted air can cause death.

This grim reality reminds me of the hit song by the Lovin’ Spoonful…

Hot town, summer in the city
Back of my neck getting dirty and gritty
Been down, isn’t it a pity
Doesn’t seem to be a shadow in the city

All around, people looking half dead
Walking on the sidewalk, hotter than a match head…

At the end of the song, John Sebastian promises that getting the girl makes everything alright, despite the heat. But when I look at the science, I’m not so sure…

Heat and bad air cause dangerously high death rates

For the study, researchers analyzed nation-wide daily air temperatures and air pollution indexes between 2000 and 2012. Then, they compared that data to daily death rates by zip code among U.S. Medicare participants over the same time period.

Turns out, higher temperatures and poor air quality significantly increased death rates — particularly among elderly adults, women, African-Americans, and those with low income levels.

And for each day-to-day increase of 10 micrograms per cubic meter in fine particulate matter (PM) — the small particles of soot in the air that easily enter the lungs and then the bloodstream — there was a 1.05 percent increase in deaths.

Worse yet, the risk remained high even at levels the Environmental Protection Agency (EPA) considers “safe” according to the standards established under the Clean Air Act.

More in the mix than just pollutants

Now, I’m not downplaying the ill effects of breathing bad air, but as I explained earlier this year, there’s probably also a genetic component at play here…

In fact, an enzyme called alpha-one anti-trypsin (A1AT) plays a big role in your individual susceptibility to inhaled contaminants. About 90 percent of people have genetic variants of A1AT that protect the lungs against moderate exposure to contaminated air — including pollution and smoke.

But 10 percent of people have genetic variants that don’t work well. And these folks are far more susceptible to lung damage from pollutants and smoke inhalation.

Mind you, exposure to polluted city air is probably far worse than exposure to smoke from a controlled, burning wood fire. (Humans have been sitting around open fires for a million years, so the body knows how to react.) But polluted city air exposes us to new, foreign contaminants…so even those of us with the protective A1AT enzyme might not respond well.

My advice?

Make sure to get out in Nature and breathe some clean country air this summer. And look to explore places that grow blue-green, yellow, white, and even reddish lichen (what most people call moss). Lichen can only grow where the air quality is good, so it’s a sign the air’s good to breathe.

And, since the effects in the new study were observed day-to-day, even just one day in the fresh air can make a difference. That’s good news if you live in a city. Just make sure to get out in Nature as much as you can.


1. “Association of Short-term Exposure to Air Pollution With Mortality in Older Adults,” JAMA. 2017 Dec 26;318(24):2446-2456