David Mudarri is a retired senior scientist with the Indoor Environments Division of the U.S. Environmental Protection Agency (EPA), with over 20 years experience in indoor environmental quality. The views expressed in this interview are his, and do not necessarily reflect those of EPA.

 

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HC: How serious is the problem of indoor air pollution from cleaning products?

Mudarri: Indoor air pollution is a serious problem, and cleaning methods and products can have a substantial impact on indoor air quality, particularly for the user and those in the immediate vicinity of products being used.

Cleaning is a double edged sword. It removes unwanted pollutants from the home but can also cause the home to be polluted, particularly if products are not used correctly.

Many cleaning products have chemicals that can be toxic at high doses, so it is extremely important to follow principles of good practice when using them. These include, for example, following instructions on the label carefully, using only as much as is needed to do the job, and properly diluting the product to the correct concentration when using concentrates. In addition, it is always a good idea to open a window in the room when possible to provide added ventilation in the space when cleaning.

HC: What statistics are available to show the impact of poor cleaning on IAQ and health?

Mudarri: There are a number of studies in this country and in Europe that show associations between levels of dust and airborne particles and health symptoms, and also studies that show health symptom improvements with thorough and frequent cleaning regimes.

We also know, from Worker’s Compensation claims, of health and safety problems experienced by cleaning personnel that resulted from overuse, misuse, or accidents when using cleaning products with harmful chemicals. That is why, in the commercial cleaning industry, there is a movement now toward cleaning for health, not just for appearance, and cleaning standards and practices are being developed to improve the “science” of cleaning.

HC: Do you recommend that consumers use “green” cleaning products to protect the indoor air and environment? Should disinfectants be used routinely or only in special cases?

Mudarri: The concept of “green products” is to minimize the harm to the environment in the manufacture of products as well as their packaging, distribution and use. So the concept is a very useful one because it reflects an ethic which is protective to both the environment and to the public health. But the green movement is at its embryonic stages, where the passion for it has sometimes outstripped the scientific and objective information that is available to support many of the claims made for individual products or practices.

Most criteria for green cleaning products are based on the chemical content. Using products with low toxicity content is a useful strategy for minimizing chemical accidental exposures of the user, but it is not the best measure of the actual pollutant emissions into the air that impact indoor air quality, so there is plenty of room for improvement.

In any case, the best consumer is an informed consumer. Buying green products is a good idea, but consumers should not stop at just reading the green label. They should seek out more information about chemical content and emission rates where it is available, and remember that while a product may have been designated as green by the manufacturer or other group, it may still have potentially serious health or environmental impacts. Consumers should use all products, including green products, wisely, following manufacturer instructions, paying heed to cautions and following good practices as mentioned above.

As for disinfectants, it is important to recognize that disinfectants are designed to kill living organisms, and should be used carefully and only in circumstances where disinfection makes sense from a health standpoint. Disinfectants per se are not cleansers, so they should not be used if the main intent is simply to clean a surface.

HC: Which types of products should be avoided or minimized when cleaning?

Mudarri: From an indoor air or public health standpoint, the idea is to use the least toxic or least corrosive product that is needed for the purpose at hand, and use just the amount that is needed. Remember that cleaning effectiveness is also important. Thus, if you find that you have to use twice as much of a product that is just a little lower in toxicity than an alternative to get the job done, the product with slightly lower toxicity content will end up being more toxic when used.

A number of organizations such as the Janitorial Products Pollution Prevention Project have published information on common chemicals that are found in cleaning products and what their relative toxicity or corrosive properties are. Most of this information is for commercial situations, but it applies equally as well to household products, so it is a good idea to do a little research and become educated. Then use good judgment, keeping in mind the general principle of accomplishing the task with as little toxicity to you and the environment as possible.

HC: Which types of vacuum cleaners are best for minimizing airborne particles? Is HEPA filtration always needed, or is overall system design equally important? How about soil removal: how does a consumer determine whether or not soil, allergens and other contaminants are really being removed from carpet?

Mudarri: Vacuuming can be a significant source of airborne particles in the home. For people with allergies or other respiratory illnesses where airborne particles can be a health problem, it may be necessary to wear respiratory protection, or to have someone else vacuum while you are away and return to the house only after the particles have settled.

Unfortunately, particles are released into the air from two sources — some escape from the bag or capture device, and some enter the air directly from the contact of the vacuum head and beater on the rug.

HEPA filters are used to reduce the particles emanating from the bag, but a HEPA filter on the bag will not capture particles that emanate directly from head and the beater. High efficiency filters also must maintain a tight fit to be effective, so this could be a design and maintenance issue. Thus, both the design and the filtration are important, and there is no pat answer to your question.

While there is no single agreed-upon standard for testing, organizations such as Consumers Union conduct independent tests of vacuums and other products, and provide consumers with information on both their effectiveness in cleaning, and in their ability to minimize airborne particles. The Carpet and Rug Institute also has a vacuum cleaner certification program where they test for both efficacy and airborne dust.

HC: What dusting methods work best? Is it better to sweep, dust mop, or vacuum a hard floor?

Mudarri: In terms of airborne particles, in general, damp methods tend to work better than dry methods. High-capture dusting cloths are better at capturing dust than ordinary cloth, although cloths may be chemically treated so that could possibly be a problem. Sweeping a floor generates a large amount of airborne dust relative to mopping, especially mopping with a damp or high-capture mop. The amount of airborne particles from vacuuming, of course, depends on the design of the vacuum.

HC: What impact does wet carpet cleaning have on the indoor environment? Do you advise consumers to use both extraction (wet) type carpet cleaning as well as interim methods (dry powder techniques) for maintenance?

Mudarri: In general, I don’t have much information on the relative effectiveness or indoor-air-quality impacts of wet extraction methods versus dry powder techniques. I do know, however, that a wet carpet can be a significant source of moisture in a home and, if provisions are not made for adequate drying, can result in moisture accumulation and mold.

This has happened in schools that scheduled carpet cleaning at the beginning of summer break, then closed up the school before the carpets were adequately dried. Without adequate ventilation, the moisture levels in those schools became high enough to create mold problems throughout the school. So my advice would be to extract as much water as possible from the carpet and provide enough ventilation for complete drying of the carpet and a return to normal moisture levels within a 24-hour period.

HC: What preventive steps should be taken to minimize the need for cleaning to begin with?

Mudarri: Keep the dirt out of the house. Much of what we clean in the house comes from outside on our shoes. A good walk-off mat outside all entryways where people can wipe their shoes, followed by a rough textured carpet inside will go a long way toward keeping dirt from entering the main part of the home. If shoes are particularly dirty or muddy, encourage people to take them off before entering.

Another source of particles is from combustion. Avoid smoking in the home, minimize the use of candles, use your kitchen exhaust fan when cooking and ensure that the fan exhausts the air directly to the outside. Also, when using a conventional wood-burning fireplace, make sure there is a good draft to draw combustion particles and gases up the chimney and keep them out of the house.

HC: What should consumers do when they discover mold growing in their home?

Mudarri: EPA has an excellent guide for consumers entitled "Mold, Moisture and Your Home" which is available at www.epa.gov/iaq. It provides a lot of information on mold, how to prevent it, how to clean it if it is found, and importantly, how to decide if the problem is serious enough to warrant professional help. I highly recommend this document.

If the problem is small enough to do it yourself, the first thing to do is to clean the mold off of the surface it is growing on if that is possible. If the mold is on a hard surface it should be cleaned with a detergent. If it has penetrated deep into a porous surface such as drywall or fabric, it may be necessary to discard the material.

The second and equally important thing to do is to prevent the mold from returning. Since a mold problem is always traceable to a moisture problem, the way to prevent mold is to solve the moisture problem. It may be a plumbing or roof leak or a condensation problem that must be fixed. Mold will frequently grow in bathrooms. Exhausting moisture-laden air from the bathroom while showering can help prevent mold from growing. Details for both cleaning and preventing mold problem are well covered in EPA’s mold document.