DEAR MIKE: I've heard a lot about the dangers of carbon monoxide in the home. Would I be smart to install a carbon monoxide alarm? If so, how many should I buy and where should I put them? -- Helen J.
DEAR HELEN: You'd be very smart. Carbon monoxide (CO) is the No. 1 cause of poisoning deaths in the nation, accounting for several hundred deaths each year, deaths that could have been prevented with an inexpensive alarm.
CO pollutes the air inside your home. It is absorbed into your bloodstream, reducing the blood's ability to carry oxygen. In a light exposure to CO, you may experience flu-like symptoms, such as headache, vomiting, nausea and general tiredness. With heavy exposure, you'll get a severe headache, and feel sleepy and/or confused. Heavy exposure can also result in unconsciousness and/or death.
CO is an invisible, odorless gas that is the byproduct of burning gas, oil or wood. Areas of concern are furnaces, fireplaces (especially wood-burning), gas water heaters, gas ranges and portable generators. Attached garages are another area of concern when a car is started there and left idling.
Normally, appliances vent CO outside through vent pipes, flues, chimneys, etc. A problem arises when these vents become blocked or broken, and the CO enters the living space. Also, as homes become more energy efficient with fewer air leaks, the natural drafting of CO through these vents is decreased, making it easier for CO levels to build up inside the house.
An alarm costs between $20 and $45. Less expensive ones are battery powered and can be wall-mounted with a couple of screws, while high-end models have a digital readout that displays the level of CO in parts-per-million. These models also display the peak CO level, and although the level may not be high enough to trigger the alarm, you can monitor the reading and see if the level is rising. These units plug into a standard electrical outlet.
A low level of CO is generally considered to be less than 50 PPM, while a reading of 50 PPM to 100 PPM is considered mid-level. A reading that exceeds 100 PPM is considered high or danger- ous. The alarm should sound when it reaches 70 PPM.
The degree of danger to an individual depends upon one's length of exposure as well as one's personal health. People are most vulnerable to the buildup of CO in the bloodstream during sleep so, at a minimum, install an alarm near the bedrooms on each floor of the house and in a location where there are no drafts. Consult the manufacturer's recommendations that are included with each alarm.
If the alarm sounds, get to fresh air immediately, and ventilate the house by opening doors and windows. Call a professional to evaluate and repair the source of the CO.