Building Air Quality

Removing Mold From Building Surfaces

The issue of biological contamination inside commercial buildings is becoming more important in the indoor air quality (IAQ) venue. The problem has always existed: however, the increased awareness of building occupants has brought it to the forefront. Correcting problems that allow microbes to grow is still the most important way to resolve the issue. But what do you do about growths that have already started and need to be removed?

Removing a microbial growth from building surfaces requires the use of a sanitizing or disinfecting agent. Selecting the right compound is important. The best treatment you can use is one that is fast-acting, works on a broad range of pathogens, is cost effective, and does not leave active residual chemicals. Sounds fairly simple doesn't it? Actually it is, and again it isn't. That's because the most important issue in your selection process is to ensure that the chemical used does not leave residuals, resulting in more problems for the building occupants' health.

In the past, property managers have called BAQ to ask if the use of a chlorine solution was sufficient to remove and kill the growths. While the answer is yes, the downstream problems that can occur from the use of chlorine may increase your risk of liability.

During the past few years, the use of chlorine dioxide has become more popular with water intrusion experts, duct cleaners, and ultimately IAQ consultants. That's because chlorine dioxide works exceptionally well on a wide range of microorganisms in a very short time. In addition, chlorine dioxide breaks down to a simple salt, eliminating any chance for toxic residue to exist.

Don't be confused into thinking that chlorine and chlorine dioxide are the same. They are separate chemicals that react differently. In addition, their chemical by-products have little in common.

Chlorine reacts by "adding" chlorine atoms. This can create trichloromethanes and dioxins, both known to be powerful carcinogens. In addition, the concentration of chlorine that is needed to be effective is too high to use safely.

Chlorine dioxide typically reacts with organics through the addition of oxygen. When chlorine dioxide reacts, it is reduced to the chlorine ion, which is part of the salt found in sea water and table salt.

If you are faced with the presence of biological growths in air delivery systems or on walls and wall coverings, you should consider the use of chlorine dioxide over chlorine for its sterilizing abilities and the reduced potential for exposure to long term liabilities.

Remember to always study the Material Safety Data Sheet for any product first, to ensure that the staff who will ultimately apply the product do so in the safest possible manner, and using the proper equipment for the job.