When I was a kid, I figured that swimming-pool owners wanted me to take a shower before I got in so I wouldn't notice how blasted cold the water with which they filled that pool actually was. And since there was also usually a chilling little breeze teasing the pathway from dressing room to poolside, I often skipped the ritual entirely because it was uncomfortable. I remember once standing at a sink and wetting my hands, then dragging them through my hair so no eagle-eyed pool employee would send me back for a do-over. I was 10.

It turns out they wanted me to take that shower to reduce the amount of garbage I might be bringing into the pool. Who knew?

During a public health conference that I covered in Midway this week, an air-quality session offered a take-home message on the importance of individual action to impact even a big, hard-to-control problem like air pollution, which carries serious health risks, especially for vulnerable populations. The public and the decisions that individuals make really do help determine air quality on a given day.

Individually, we don't control air quality. But it's a cumulative thing, one good or bad action stacking on top of another to help shape the end result. And while we can't control the weather or whether air's socked in because of it, we can make pollution decisions that, added together, have a real impact for good — or the opposite, if we get it wrong.

When the air's already bad, we each need to keep from creating more pollutants by choosing not to idle our motors or make optional car trips. If we must drive, we can bundle errands together and plan a route that takes us fewer miles. We can even decide it's probably not the best day to mow the lawn, since small engines contribute pollution, too.

We can do the same things on days when the air's better, in hopes of keeping it that way.

Looking at the agenda of the conference, I was struck by how many different ways Jane and John Doe can actually affect public health, across a bunch of topics.

We can help battle the parasite cryptosporidium in swimming pools by staying out of the water if we've been sick recently. Ditto for obeying the rules that tell us to take a real shower before we get in the water. It's no harder to change the baby's diaper in the dressing room. And where, by the way, were you planning on washing your hands as you knelt by the pool, anyway?

One of the best ways to limit an infectious outbreak like cold or flu is to not pass it on or put yourself in a position to be its next repository. Warnings to skip that trip to the mall when you're sick or forgo that concert — even though you stood in line for tickets three months ago — protect you. And they protect other people from you, should you happen to be harboring illness.

I used to joke about not taking sick days. "I might as well be miserable here." I figured folks who took a day off just because they had a cold were wimps.

Why you stay home finally sunk in the day I was standing in line at the food court of a local mall and someone behind me sneezed gustily directly into my hair. Yuck. And sure enough, a couple of days later, I was sick. These days, I appreciate the "wimps" who keep their germs to themselves.

I get a flu shot each year, admittedly mostly for my own comfort, but also for those on whom I intend to inflict myself.

And a couple of times a year, I make the drive to the landfill, veering off to the hazardous material drop-off station to deposit worn-out paints and solvents, lawn fertilizers and weed killers because I finally get that some things are more important than convenience. Dumping comes back to bite all of us.

They're not big steps. They won't eradicate all ills. But they're not hard, either. And they add up.

Deseret News staff writer Lois M. Collins may be reached by e-mail at lois@desnews.com