Is paying attention to the air quality index crazy?

Cecil's Columns/Staff Reports
1

http://www.straightdope.com/columns/read/2923/is-paying-attention-to-the-air-quality-index-crazy

I think Cecil didn’t quite address the actual question, at least as I understand it. Sure, there’s no doubt that bad air is bad for your health. On the other hand, there’s no doubt that exercise is good for your health. The real question here is not, IMO, whether you should exercise in good air or in bad air, but rather - given bad air - whether you should exercise or not. And in that case, there’s a trade-off between the health advantages of exercise and the disadvantages of bad air. But the bad air is a given in that situation.

So the question (my question, at least) is: Does exercise aggravate the adverse health effects of polluted air? Here we should distinguish short-term and long-term effects. Cecil only addressed short-term effects, which are different for different people, depending on their sensitivity. But let’s assume that littleWaki’s brother does not experience any immediate effects when he jogs through the smog. What are the long-term effects?

Again, it’s not about what kind of air you wish for. My question is: Do the (adverse) long-term health effects of polluted air increase through exercise, and if so: to what degree do they increase, and does this outweigh the beneficial effects of exercise as such? Keep in mind that you will inhale all the pollutants even if you don’t exercise, you’ll just do so a little more slowly.

As a comparison: We all agree that second-hand smoke is bad for you. But given that you have to spend time in a smoke-filled room, should you breathe normally, try to breathe less, or stop breathing altogether? There’s a rather similar question that I think was discussed in the Straight Dope once. I can’t find the column, however, so maybe I’m wrong on that point. I do remember both the question and the answer, though: The question was whether you should shut down the ventilation in your car when you’re in heavy traffic to keep out all the exhaust fumes. The answer was that you should keep it open even though you’ll draw the fumes in because it would be worse to use up all the oxygen in the car and not replace it.

So, referring back to the original question, it would not seem implausible that the added intake of pollutants through exercise in bad air is less significant for your long-term health than a possible lack of exercise (short-term effects excluded). Cecil never addressed this thought.

2

Unless “exercise” is defined in quantitative terms, the question is meaningless.

It is also meaningless until the relative frequency of various non-green days and the health of the subject can be quantified, too.

3

If only there’d been a little airplane on the treadmill.

4

Speaking of air pollution-

I recently had an electric washer/dryer stack installed in my condo. Due to the layout of the building and the location of the water hookups, the dryer does not vent outdoors but rather into a “vent bucket,” a small plastic bucket that holds a few cups of water with a gap for air to escape. When running the dryer, a fair amount of moisture is expelled into my unit- should I be worried about anything else that might be spewing out? How much am I affecting the air quality of my living space?

5

Strictly speaking, you may be right. But if we rigorously required every aspect discussed in the Straight Dope to be quantified, most of the column, forum etc. would probably become meaningless.

Besides, there may be pertinent studies that do quantify all this. But since the question has not been researched in this direction, we haven’t seen them.

6

“Studies” may have quantified some things, but the original poster didn’t provide the information to apply to his question.

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Here in Hong Kong, we’re told to stay indoors when the pollution is bad (which is very often). But what difference does it make? My air at home isn’t filtered, and the air in the office simply goes through the aircon system, and I doubt that removes chemicals or particulates.

Is there any value to staying indoors on a polluted day? Do modern buildings’ aircon systems remove harmful matter from the air?

8

I can’t help with quantifying, but exercise does aggravate the effects of pollution. That’s because the more vigorously you exercise, the deeper you breathe. When you exercise, the pollutants get into parts of your lungs they wouldn’t get to otherwise. Those are the deeper and finer parts, and I believe they are harder for the body to cleanse, and perhaps more sensitive.

As for indoors vs. outdoors, the pollution is the same in or out, and from my observation, indoors follows outdoors pretty quickly, even with the windows closed. (I pay close attention, since I’m particularly sensitive to air quality.) The exception is if you have a good air filter AND a pretty well-sealed dwelling. Normal air conditioners won’t filter particles that small. Small air leaks can make a lot of difference, same as when you’re sealing your dwelling to save heating costs in the winter.

BTW, if you’re looking for an air filter, shop carefully–do some homework. Quality varies widely, even between products from the same maker. Price doesn’t correlate with quality. You want a HEPA filter. Avoid filters with ion generators–they can cause problems too, at least for some people.

9

AFAIK, ozone is created in larger quantities in the sunlight. Something like: oxygen + nitrogen dioxide + sunlight → ozone + nitrogen monoxide. In the shadow, this reaction tends to run backwards. Thus, there should be less ozone indoors. This has nothing to do with aircon and whether or not you open the windows.

As for other pollutants, I dunno.

10

Ah, here we get to the interesting parts. I kind of doubt (without any particular evidence, admittedly) that those deeper, finer parts of the lungs would not be reached by pollutants in the long run even without exercise.

Let’s assume that you breathe dirty air day in, day out. I can see three scenarios following from here: [ol][]If the deep parts of the lungs are used at all, the dirt should get there eventually. []If they are not, they are of no use anyway, and it doesn’t matter if they get clogged up or not (unless this would cause cancer or something, which might as well occur in the upper lungs). [*]If they are used only under physical exercise (and only get clogged up under same), then exercise may be less effective, but you wouldn’t miss the function of those parts of your lungs the rest of the time. And even less effective exercise may be better than none at all.[/ol]Anyone follow my argument here?

11

I’m curious just how bad running on a poor air quality day is for your overall health.

Presumably if I go on a 5 mile jog, my average lifespan will:

-increase by X minutes for various reasons (I’m getting some exercise, I’m getting some vitamin D from the sunshine, etc.)

-decrease by Y minutes because I’m breathing in more pollution than usual

-decrease by Z minutes for various other reasons (I could be hit by a car, I could be hit by lightning, I could could cause permanent injuries, etc.)

Obviously, Y will be bigger on poor air quality days, but without knowing the relative size of X, Y and Z, that’s not saying much.

12

That’s just my point, except that I neglected Z. (I’d guess it’s negligible, but being thorough is a good idea.) Of course, there’s the problem of quantification as mentioned by John. Still, there may be some useful information out there.