Sh**t ,I smoke - Air Pollution and Your Health

It’s 9 am, Wednesday Feb. 16. Sudbury’s Air Quality Health Index is already in the “moderate risk range” at 4. Based on current levels of air pollution, I’ll be  smoking two-thirds of a cigarette today.

Let me be clear – I don’t smoke, and as befits a 21st century health professional, I try to convince every smoker I meet to persevere in trying to quit. Cigarette smoking is a risk factor for a multitude of lethal health conditions. Smokers are often miserably short of breath. They also look older and die younger. So it might be disturbing to learn you can download an app that converts the health impact of your air pollution exposure to the equivalent number of cigarettes smoked. Appropriately, it’s called “Sh**t! I smoke”.

In 1979, I dissected a cadaver. It was one of the less pleasant tasks required of first year medical students, but it’s a right of passage that still persists. The preserved body I shared with my three classmates was an elderly fellow who’d clearly been a smoker. When we opened up his chest cage, we saw not the dusty-rose colour of healthy lungs, but the brownish-black tarry residue of burnt tobacco, which had accumulated over many decades.

Each cigarette the man smoked also delivered a hefty dose of tiny particles, known as particulate matter or PM, to his airways and lungs, not to mention those of his wife and children, who were probably forced to breath his second hand smoke.

PM2.5 is a major component of both cigarette smoke and air pollution. Though some PM2.5 is of “natural origins,” most of it arises from burning things: fossil fuels, tobacco, firewood, cow dung, agricultural waste, forests, peat bogs, garbage, and other industrial nastiness. Some particles are emitted directly through burning, or kicked up into the atmosphere by human activities like driving or construction. Others are formed in the atmosphere through chemical reactions between toxic air pollutants like sulfur dioxide (SO2), nitrogen oxides (NOx), and volatile organic compounds (VOCs).[1]

Airborne particles comes in an array of sizes. Larger ones, like dust and pollens, are classified as PM10. They will generally get trapped by the hairs and mucous in our noses and airways, and coughed or blown out. However, smaller ones can fly right past the defences of our respiratory tracts to reach the tiny air sacs deep in our lungs where oxygen and carbon dioxide exchange takes place. From there, they penetrate into our blood streams and organs, often carrying toxic chemicals on their backs. Suffice it to say, they are not good for us.

On a bad day in Beijing, the mathematical models used by the Sh**T! I Smoke app might cough up an equivalency of 25 cigarettes per person per day. With air that smoggy, researchers no longer have to resort to studying smokers to sort out the impact of life-threatening levels of air pollution. But perhaps Beijing’s 21 million citizens will find it reassuring that, on a more average day in their city, every man, woman, and child (and baby) only smokes four cigarettes. The U.S. average is lower, a mere 0.4 cigarettes per day. However, residents of air pollution hot spots like Toronto, Vancouver, and Los Angeles are advised not to take comfort in national averages.

Newer research suggests there’s no safe lower limit for PM2.5 exposure, whether from smoking or air pollution. The closer we get to zero, the better our health outcomes. And no sensible parent these days wants their children to smoke. Not even two-thirds of a cigarette a day. So may I suggest we stop burning stuff?

[1] Some VOCs arise naturally from vegetation, but you can also get an unhealthy dose of them by sitting in a new car.