(Picture by Jeffrey M. Vinocur)

There are many potential poisons in the air in the modern home. Some can cause long term damage to your health, and some can kill you. These hazards are all the more dangerous because they are unexpected and aren't apparent to most people. Here are some of the top hidden hazards that you can protect yourself against:

1. Air Ionizers / Ozone Generators. The May 2005 issue of the Consumer Reports magazine featured a study which showed that some household air ionizers produced harmful levels of ozone. Ozone is highly unstable molecule that is highly reactive. It oxidizes anything organic that it comes into contact with, meaning that it breaks the bond between carbon atoms in organic matter. Breathing in high levels of ozone can damage the tissue in our lungs. (Click here for a newspaper article on air ionizers. Click here for an explanation of how ozone reacts with organic molecules.) If you must use air ionizers, use it when no one is in the room. Then shut it off before you enter the room, and allow some time for the ozone to dissipate. The same advice applies to air purifiers that generate hydroxyl radicals. Hyrodxyl radicals are another highly reactive substance found in the upper atmosphere, where they are beneficial because they help "clean" our atmosphere by destroying harmful chemicals.

2. PVC Shower Curtains / Mattresses / New carpets. Some studies have shown that new PVC plastics, like shower curtains, emit dangerous levels of chemicals. These chemicals appear to us as the "new plastic smell". No one knows how harmful those chemicals are, but there's no harm in avoiding them. Just let new plastics air out for a while, until the "new smell" goes away, before you use them. (Click here for a newspaper article on PVC shower curtains)

3. Carbon Monoxide - Furnaces, Stoves, Heaters. Anything that burns fuel, such as a car engine, a furnace, a gas-fired water heater, propane powered BBQs etc. can emit carbon monoxide if there is incomplete combustion. Carbon Monoxide is a tastetless, odorless and invisible gas that can cause death if you breathe it for more than 1-2 hours. It is especially dangerous because most people won't know when they are breating it in. You can't smell it, you can't see it and the symptoms of early Carbon Monoxide poisoning resemble a mild cold: dizziness, nausea, headaches and shortness of breath. The best way to protect yourself is to install Carbon Monoxide detectors around your home (they are not the same as smoke detectors). Don't fall prey to carbon monoxide poisioning. If you go to sleep in a room filled with carbon monoxide, you'll will die in your sleep.

4. Laser Printer Toner. If you use a laser printer at home, you don't want to sit too close to it. A study done in Australia found that many laser printers emit small particles of material, believe to be toner residue. These particles can get into our lungs and damage our respiratory tract. There is an Australian news report on the study here. Some printers also emit small levels of ozone, which irritates the lungs.

5. Air fresheners and Cleaners. A study done at the University of California, Berkeley, and Lawrence Berkeley National Laboratory found that when some of these products sprayed in small rooms, the level of (ethylene-based glycol ethers and terpenes) chemicals in the air can exceed safe levels. Some of these chemicals react to ozone in the air and create toxic pollutants. To be safe, don't overuse these products and only use them in well ventilated rooms.