Modern homes are sealed to keep out drafts. Unfortunately, that means that they keep indoor  toxins in. That is, the air in your home may be more polluted than the air outside. Since we spend more time indoors than our ancestors did, it can endanger our health. Fortunately, keeping healthy indoor air requires only a few simple steps.

Maintain your furnace

Do you have a forced warm air furnace? Then you have at least one air filter to maintain. You should at least get filters that block lint, household dust, mold spores, pollen, and smoke. Speaking of smoke, if you smoke, stop. Tobacco smoke dirties indoor air the way it dirties you lungs. Also, be careful about fireplaces, candles, and incense.

Some filters also block bacteria and viruses. Be careful with those, however. The pores are so tiny that they can keep adequate air from returning to the furnace. Put in a new filter at least every three months, the virus-blocking ones even more often. And keep an eye on it. Change it when it’s dirty, not according to the calendar.

Use a humidifier

In the winter, the air in our homes can be dryer than a desert. Overly dry air dries out our bodies. We can get chapped lips, itchy skin, and a dry sore throat.

Static electricity more easily builds up. We get a shock when we get close to something metal. Static cling makes our clothes stick to already uncomfortable skin. Unfortunately, dry air feels cooler. But if we turn up the thermostat, we only dry the air even more. Not only that, but air that’s too dry can harm our furniture and the structure of the house.

In the summer time, your air conditioner acts as a dehumidifier to keep your home from getting too moist. But in the winter, you need a humidifier to add moisture. You can get one to attach to your furnace or smaller room humidifiers of three different basic designs.

Open windows and doors

Indoor air becomes stale if it isn’t exchanged for outside air. Even modern sealed homes allow some outside air to enter and drive out the stale air. But perhaps not enough.

Even in the coldest parts of winter or the hottest parts of summer, opening doors and windows from time to time helps indoor air quality. Of course, you needn’t keep them open for very long. In extreme temperatures, normal coming and going might exchange enough air.

In moderate temperatures, when you don’t need to run either the furnace or the air conditioner, leave windows open longer.

Use houseplants

Most people probably choose houseplants for their beauty. Most people know that plants breath in carbon dioxide and breathe out oxygen. So houseplants keep indoor air from becoming stale.

Less well known, at least some houseplants can remove common air pollutants such as formaldehyde and benzine.

Control dust

Now here’s where improving indoor air quality requires some extra effort. Your air filter traps dust, but it’s better to keep it out of the air in the first place. Regular vacuuming and dusting surfaces like end tables keeps the air cleaner.

Eliminate volatile organic compounds

Modern sealed buildings lead to so-called sick building syndrome. People who live and work in sick buildings suffer a variety of allergy symptoms. These come not from the sealing of the building, but from volatile organic compounds (VOCs). Certain solids and liquids––thousands of products in all––emit these possibly toxic gases.

Some VOCs come from new carpeting or furniture. Most of them come from products for cleaning, disinfecting, or, ironically, air fresheners. Cosmetics, dry-cleaned clothes, bug-killers, paint, and various hobby products also emit VOCs.

If a product––bleach, for example––stinks, you’re smelling a VOC. The stench indicates a toxic chemical.

Unfortunately, in our sealed buildings, VOCs linger in the air long after we’ve finished using the products that emit them. Concentrations of VOCs are higher indoors than out, regardless of whether the building is in an urban area with bad air or out in the countryside. Indoor air may have twice or even ten times the concentration as outdoor air.

Houseplants and air filters remove some of these pollutants, but it’s better not to turn them loose in the house in the first place.