Simply put, the answer is "Yes". You can create dangerous smog levels in your own home with an ozone-generating air purifier. The finding comes from a study of ozone-emitting air purifiers by Sergey A. Nizkorodov, PhD, from the University of California, Irvine. There researchers studied 13 air purifiers known to give off small and large amounts of ozone, a major ingredient in air pollution.

Several ionic air purifiers made by The Sharper Image, including the popular Ionic Breeze Quadra, which produce detectable levels of ozone. But they did not emit dangerous levels of ozone, except when a Quadra model intended for a large room was tested in a tiny bathroom.

Ozone generators, however, were a different story. As they are designed to do, they put a lot of ozone into indoor spaces. The devices quickly caused ozone build-ups to levels that can trigger severe smog alerts for outdoor air.

This becomes problematic as exposure to ozone irritates and inflames the lining of the respiratory system, and causes symptoms such as coughing, chest tightness, and shortness of breath. Ozone can also worsen asthma symptoms, with one study indicating that ozone may contribute to the development of asthma itself.

The dangers of ozone continue as elevated exposure can cause permanent lung damage, and repeated exposure can be potentially fatal among people with ailing health. People especially vulnerable to ozone hazards include children and those who suffer from asthma or other respiratory diseases, including the elderly.

Ozone Generators vs. Ionic Air Purifiers

Ionizing air purifiers, because of their electric charge, do create ozone. Consumer Reports has warned that they may give off potentially harmful ozone levels.

Mark Connelly, senior director of appliances and home improvement for Consumer Reports, oversees the magazine's air-cleaner tests.

"You don't want to say that anything that generates ozone is bad," Connelly tells WebMD. "A printer produces ozone, but just because printers sit on people's desks doesn't mean they should be taken off the market. But the people who buy air purifiers are most susceptible to the problems they create. You buy it to make things better, and it ends up making things worse for you."

Whatever ozone comes from ionic air purifiers pales in comparison to the amount produced by ozone-generating air purifiers. These machines make ozone for one reason, and that being that that's what they are designed to do.

"Ozone is a very effective way of disinfecting water - and some believe it is also possible to do this in the air," Nizkorodov says. "Unfortunately, at the concentrations you need to destroy germs and pollutants, the ozone levels are so high you cannot safely use it."

In a small bathroom, the UCI researchers found that one ozone generator, the EZ-COM Air Purifier, took only a half hour to build up ozone to a smog level that would force school closings if detected in a city's air. In a 1,250-square-foot office, the device took about a half hour to build ozone to smog levels that would trigger unsafe air alerts.

However, studies show lower level of air purifiers is relatively safe, but still not ideal as they don't actually purify the air.  The next question becomes: how effective are air ionizers over air filters.

Ionic Air Purifiers vs. Air Purifiers

Ionizers simply get rid of the charge in a dust particle so that they stick to surface rather than linger through the air. However indoor air purifiers have the ability to actually eliminate odors though a carbon filter.

Ionic air purifiers only spit out negative ions that neutralizes oxidizers. As a result, dust becomes statically charged and sticks to a surface. However, ionic air purifiers cannot actually clean or filter the air.  On the other hand, air purifiers with HEPA filters and carbon activation can eliminate mold spores, odors, smoke, pet hair, and be used to treat allergies, asthma and provide a pristine indoor air quality for home, office, and medical uses.

If you want safe and EPA approved air cleaners, consider the BlueAir Air Filter, the AustinAir Air Cleaner, and the IQ Air Purifier. 

Summary of this week's top green technology news from around the web:

UK-based Siemens Mobility Traffic Solutions is re-inventing the traffic light.  By replacing the energy-inefficient tungsten-halogen lights by a cluster of LEDs, the company expects to reduce the energy usage to less than 25%  and maintenance costs as well.

A biofuel demonstration flight will take place today at Schiphol Airoprt in Amsterdam.  UOP LLC, a Honeywell company, created green jet fuel from renewable feedstocks.  Camelina, an inedible plant, was used to generate the biofuel.  This flight will be the first to carry observers and the first demonstration of its kind in Europe.

Masdar City may become the world's first city with zero carbon emissions and zero waste.  40,000 to 50,000 people are slated to live in this city conceived by Abu Dhabi.  15 billion in seed money has been put up for this venture.

American think-tanks have concluded that Asia is set to dominate the clean technology market.  China is duplicating the strategies employed by Japanese and Korean governments to establish a technological lead in other markets.  China is already the world's biggest exporter of solar power products and has one of the largest wind-power industries.

ZeaChem, a biofuel startup company, is building a pilot plant that will manufacture ethanol from cellulosic feedstocks using microbes found in termites.  Instead of using yeast to ferment the sugars into alcohol, the sugars are fed to a bacteria found within various insects including termites. This results in significantly higher yields than other production processes.

One of the world's largest brake pad manufacturers, FRAS-LE, is about to introduce a new environmentally-friendly hybrid material for use in friction applications such as brake pads.  The material doesn't contain chemicals such as asbestor, lead, mercury, lead, chromium, nickel, antimony or copper.  The material meets California's 2032 legislation, 22 years ahead of time.

Did you know that many electronic components draw power even when they are not being used?  For example, a friend of mine once indicated that his satellite dish receiver used 35 Watts of power when turned off.

You can detect conditions like this in your home by acquiring a kill a watt (or similar) power meter.  By placing the power meter between the device and the electrical outlet you can determine electrical usage by that device in ON and OFF state.

You can buy a kill a watt power meter for under $25.  In some areas you can borrow a meter from the public library for free.

Other common conditions you may discover are devices that consume more power than manufacturer's stated wattage, sometimes as much as 50% more.  Use of a power meter is a good first step in reducing your home energy usage.