As a public educator on indoor air quality, Ted Funk from the University of Illinois Extension fields a lot of questions about mold.

He wishes he received more about radon.

Mold is important. It presents a health concern. It can aggravate respiratory conditions.

But radon gas is deadly, the second-leading cause of lung cancer behind cigarette smoking.

Mold problems are evident from the resulting musty smell if not from visual evidence. Radon is odorless. It is a naturally occurring process, and measuring it requires a special test.

Professional air tester John Brue (pronounced "brew") notes that residential indoor air quality remains unregulated. Whether that's good or bad, he said, it means problems aren't necessarily addressed. Air pollution usually is discussed in the context of the outdoors, but he believes the quality of indoor air needs attention. Here are some of the issues.

Radon testing

Radon requires a test, but the tests are cheap. Home radon test kits are available at hardware stores or, for free, at www.state.il.us/iema/radon/RadonTestKit.asp.

Funk said the home test kits are effective when directions are followed properly. Don't assume that newer construction is safer; to his dismay, he said, the construction industry isn't universally vigilant in radon testing. And as an airtight home lets less gas escape than an old drafty house, newer construction actually may pose a greater risk.

If high levels of radon are discovered, the Illinois Emergency Management Agency (IEMA) recommends using a licensed professional to install a mitigation system. It will cost $800 to $1,200, plus about $100 per year to run the fan for a radon mitigation device, IEMA says.

The U.S. Environmental Protection Agency recommends that mitigation be undertaken if the level of radon is 4.0 picocuries per liter of air. At that level, the EPA says, the effect is seven lung cancer deaths per 1,000 people.

Mold issues

While mold causes less severe problems, it is an unhealthy irritant and an asthma trigger.

There will be mold spores in the air in the Central Illinois household. There's no way around it, say those involved in home-quality issues. That's why tests - by professionals as well as home test-kits - involve sampling outside the home as a way to ascertain a baseline for comparison.

Funk isn't sold on home test kits. One might cost about $150. If a problem is suspected based upon a musty smell or discolored areas, he recommends paying for a home inspector instead.

"They (home inspectors) are accustomed to poking and prodding around," he said. They also may uncover other building problems.

Inspectors such as Steve Cline will look at places that may not occur to the homeowner. Cline, who owns Accurate View Home Inspections in LeRoy, will look in the attic. Mold often is associated with basements and, after flooding, flood-affected lower levels. But he thinks of a day when friends were replacing a roof in LeRoy. "The deck of the roof was black as black could be" with mold, said Cline.

For a small mold problem - say in the corner of the basement - Cline favors fungicides, which can be purchased at stores. They can kill and seal mold. Funk recommends scrubbing with detergent.

Both warn against using bleach to scrub the wall because bleach fumes cause lung irritation.

Funk said, "You get the same job done with elbow grease, detergent and water."

They also agree on this: Mold grows with moisture, so the moisture issue needs to be addressed.

The EPA states that air conditioners and dehumidifiers can reduce home humidity, as can fans (or open windows) in a bathroom while showering and proper venting of dryers. It further states that windows can be used to vent a kitchen when using a dishwasher.

When structural damage to homes is allowing water to seep in, say specialists, the damage must be fixed or the mold will return.

After the flood

Flooding like that seen this winter in parts of Illinois is causing mold problems. Crucial to avoiding mold growth is to dry out affected areas within 24 to 48 hours, said Funk.

Those with unfinished concrete basements were spared the worst of it, he said. But in cases where carpet, drywall, some types of insulation and pressed-board paneling got wet and stayed wet, professional assessment probably is required, said Funk.

In many cases, he said, the healthy but expensive decision will involve discarding building materials.

The EPA recommends discarding all carpet soaked in a flood.

Carbon monoxide

Carbon monoxide is released in the home with the burning of fossil fuels and tobacco products. At high levels, the gas causes death.

Detectors for the home typically run $25 to $100. Some plug into walls. Some run with batteries. Some have both - plug-in with battery back-up. Consumer Reports magazine says 500 people in the U.S. are killed by carbon monoxide poisoning annually.

Carbon dioxide, air particles

America is entering a period of competing interests in the home. The tight seals achieved by modern construction save energy but also can create air-quality problems. One such problem involves carbon dioxide levels.

Think of a fish bowl without the aerator, the bubble-maker that helps clean the bowl and put fresh oxygen in the water. Without air interchange, the water becomes stagnant and stinky.

Indoor air isn't much different, said Brue, whose firm, Balancing Precision Inc., specializes in ensuring quality air in commercial buildings and, to a lesser degree, in homes.

As he spoke, with a reporter and three colleagues in an office room, his carbon dioxide meter read 1,486 parts per million of CO2, the effect of four people exhaling CO2; 1,000 would be preferable, he said.

Opening the window brings fresh air but in the winter is highly wasteful of energy. And the outdoor breeze, especially on a windy day, will add airborne particles to a room, Brue said. Another trade-off is involved.

High levels of CO2 can cause sleepiness or an oppressed feeling. With electronic testers costing a few hundred dollars - online models of CO2 testers run about $300 to $600 - getting one for a home would be uncommon.

Professional air quality testers have them.

The size of the home and its low occupancy means CO2 in the home shouldn't be a serious problem, but it can reduce the quality of air, especially in a closed room where two people are sleeping, Brue said.

Air exchangers

As he monitored the CO2 level, Brue wondered whether a device under discussion - an air exchanger - might be installed in his office.

Exchangers, with small ones being about the size of a suitcase, bring fresh air in and take stale air out. They will raise heating bills somewhat - though much less than opening a window in the winter. To help with efficiency, an exchanger will use the outgoing air to heat the incoming air. (Or, the reverse during the summer.) Some sort of medium, such as a metal plate, keeps outgoing and incoming air from mixing.

Air exchangers are more common in commercial and public buildings, such as schools, where equipment budgets are greater and more people are in the same space exhaling. They have a residential market is colder climates, particularly in Canada, Brue said.

Stuart Nerby, residential manager for Hermes Service and Sales in Bloomington, said he has sold only a handful of air exchangers to homeowners over a period of years.

It takes a person with a level of education on indoor air quality to want one in the first place, and the person must have means to get one, said Nerby. Exchangers can cost $1,500 to $4,000, depending on quality and size of the unit.

Another benefit of exchangers is that they create a slightly positive air pressure in the home compared to outside, said Brue. This means air will be pushed out through cracks in a building. Negative indoor pressure produces drafts and, when doors are opened, rushes of air.

Asthma, allergy triggers

The American Lung Association lists these asthma and allergy triggers: Cold air, wood smoke, tobacco smoke, perfume, paint, hair spray, dust mites, pollen, mold, pollution, animal dander, cockroaches and chemical cleaners. The triggers and level of problems depend on the individual.

Remedies, the association said, include avoiding the triggers.

Dust mites are especially problematic. The lung association recommends keeping a clean house, placing mattresses in airtight covers, washing bedding weekly in hot water, not lying down on upholstered furniture, removing carpet from the bedroom, using washable window covers and washing them regularly, reducing humidity in the home and using air filtration.

Vacuuming stirs up particles, so the more sensitive people in the household should be in other rooms during vacuuming.

Second-hand smoke

Prohibiting smoking in the building is recommended by the lung association. Second-hand smoke is a known carcinogen, it said.

Air purifiers

Room purifiers pose an issue. Some work; some are believed to make conditions worse.

Brue recommends the "HEPA" variety. It pulls air through a filter to remove particles. "I've done tests in my own bedroom and it's marvelous. In a matter of a few minutes it will take particle counts down to a fourth."

Ionizing machines are suspected of increasing asthma agitation, he said.

HVAC filters

Keep air conditioning and furnace filters clean, Nerby said. Newer models of filters can improve the amount of particles removed, he said. Air Bear, for example, makes a filter for heating and cooling units that are four times as thick as the typical air filter, he said.