As we're in that traditional time of spring cleaning, perhaps some common sense strategies to reduce dust and allergens are appropriate. In fact, what better time because as the temperature warms up so the potential for generating allergens increases. Unfortunately, few of us really know much about cleaning as we have been educated through the media trying to sell us products. Now it is time to put some science back into the equation.
In general, the less dust on a surface, the less potential there is for redispersing the dust (particles). A proper routine cleaning may eliminate or significantly reduce the quantity of particles in "sinks" (reservoirs of dust like soft furnishings), preventing the particles from being redispersed and therefore reducing exposure.
Managing Particulate Levels in Your Home
There are four basic strategies for reducing levels of indoor particulates:
1. Reducing the intake of particulates into the home;
2. Reducing the emissions of particulates from sources within the home;
3. Diluting airborne particulates by adequate ventilation; and
4. Removing particulates from indoor air.
If you use a combination of all of these techniques, you will reduce the particulate levels in your home significantly, and enjoy better health as a result. This is true for everyone in the house including asthmatics. One simple strategy we implemented a decade ago and is applied around most of the world is to take your shoes off at the front door. You would be surprised how much dust comes in on the bottom of shoes, not to mention what is in the dust.
Our own research over the years has shown that the normal or conventional vacuum cleaners used by most households are not capable of removing large quantities of dust from carpets and are, in fact, capable only of removing the larger particles of dirt and debris - the visible dust. Even many of the commercial vacuum cleaners and so-called good residential cleaners remove only a small amount of the dust trapped within the carpet. Nor do they remove larger grit particles trapped deep in the carpet, which cut the fibres and reduce its life. This means that the carpet is not even being maintained, let alone cleaned.
Our research revealed that the low air flow (suction power) of conventional vacuum cleaners brought dust up to the surface of the carpet but failed to actually remove it, leaving it where it was easily stirred by movement. The efficiency of these vacuum cleaners is reduced even more as the bags begin to fill, resulting in a lower airflow and weaker suction (they are not really vacuums). With such inefficient cleaning, dust particles gradually build up in the carpet, on furniture and in the air itself. This explains why some homes get dusty again far too soon after cleaning and why it never seems possible to keep them clean.
Poorly cleaned carpets have been specifically linked with tiredness, malaise and Sick Building Syndrome (SBS) symptoms, such as irritation of the eyes, airways and skin, as well as headaches and fatigue. So if this fits you or someone in you family read on.
Our research found that airborne dust levels were reduced for long periods by up to almost 90% after vacuuming with an efficient filtration vacuum cleaner, or after some other accredited method of professional carpet cleaning. There were also reductions in other airborne contaminants such as volatile organic compounds (VOCs) and allergen levels.
Inefficient, conventional vacuum cleaners may actually be contributing to higher levels of suspended dust. This is not just because of their poor suction. They also have more porous dust bags (cloth bags being the worst offenders) allowing the microdust to pass into the exhaust airflow and to be redistributed. In fact, airborne dust levels during and directly after cleaning with these conventional models are two to 10 times greater in homes than before vacuuming!
When you dust and then vacuum, a thin film of dust settles and becomes apparent on surfaces within an hour or so. Most of this comes from the dust redistributed by the vacuum, the rest from the activity at the time. Most vacuums, particularly those which have a bag type filter, suck at one end and exhaust out the other, releasing billions of microscopic particles which can float in the air for hours, waiting to be inhaled. These vacuum models may accurately be called "dust distributors." Their bags can also provide a breeding ground for mould, which also exhausts into the air.
New vacuum models are continually coming onto the market, with better cleaning and filtration. This is a very positive step. Sometimes, however, extra filtration can lead to poorer airflow and weaker suction.
Many vacuum cleaner companies make exaggerated claims, which are not backed up by science, about their equipment. An important selling point is often the power of the motor. In the vacuums we tested, the power of the motor had little or no influence on the efficiency of the vacuum. In fact, it was the lowest powered motor that had the best results. It is the specific design of the motor and the vacuum that makes it many times more efficient. Other sales ploys include using a new vacuum with an empty bag and comparing it to your older machine. A new vacuum is going to outperform an old vacuum, especially if your machine's bag has not been emptied recently and if it has not had regular maintenance. A vacuum cleaner will perform much more efficiently if it is properly maintained. Only one in every 200 people actually get their vacuum serviced, yet it is necessary to maintain it, just as we would a car or any other piece of important equipment.
Our research has shown the best vacuuming systems have a cyclonic/centrifugal action, with multi-level filtration capable of removing particle matter down to 0.2 microns in size. The cyclonic/centrifugal motion spins the various dirt sizes out of the air stream before it flows through the final filter. This ensures that the suction is not reduced because dirt does not clog up the filter. These models may incorporate an activated carbon or charcoal filter for removing pollutants such as volatile organic compounds and odours. They also have an attachment called a mechanical beating head or turbo head for vacuuming soft surfaces. Its special action is critical for picking up and removing the dirt from carpets, including the deeply engrained dirt.
Vacuums with water filters are often overrated. They pass the vacuumed air through a compartment of water that removes most of the dust. However, many microdust particles pass through the water either in bubbles or because they do not dissolve readily.
The use of a high efficiency vacuum fitted with a HEPA (High Efficiency Particle Attenuator) filter significantly reduces the amount of suspended indoor dust, as a HEPA microfilter is capable of trapping most of the microdust. A good vacuum cleaner salesperson will know a HEPA filter. The HEPA filter alone does not guarantee quality of cleaning, rather it guarantees cleaner air during cleaning. If not maintained regularly, HEPA vacuums will also become "dust distributors."
Our research has also shown that technique, as well as equipment, is important. Most vacuuming quickly brushes over the surface of the carpet to remove the visible dirt and fluff, but fails to remove the deeply ingrained dirt tangled in the carpet pile. The longer you vacuum in one place, the more dust and grit you will remove. Vacuuming in one place for a minute every six weeks is more effective than vacuuming that spot every week for 10 seconds. Even if you have a good cyclonic vacuum cleaner, to clean hygienically it will still take this amount of time. If you have a vacuum with a bag filter it will take double the time. However, cleaning this way keeps down the amount of microdust in the air for months.
One of our studies was conducted in an office building, where we replaced normal, conventional vacuum cleaning equipment with a high efficiency vacuum using HEPA filtration. The result was a more efficient removal of dust from surfaces, which significantly reduced airborne dust and also lowered the number of health complaints in the building. People reported fewer symptoms associated with Sick Building Syndrome (SBS). Not only did they feel better, but also because of the improved standard of cleaning they felt more positive about their work environment and became more productive. The economic benefits of cleaning impressed the company so much they initiated healthy cleaning practices based on our research.
If these principles are adopted at home, you will actually find your cleaning is more efficient and economical and your family's health will benefit. Let's say you vacuum two hours a week using a poor quality vacuum, a "dust distributor." You not only pollute the air but also have to clean twice as frequently. You could halve your effort by using efficient equipment, saving labour, time and money.
Rugs are an alternative to carpets, but they also need to be regularly cleaned and maintained. Taking rugs outside and shaking them, and putting them in the sun and occasionally washing them are all suitable treatments. In Scandinavia and Northern Europe, it is customary to take the rugs down to the river and wash them in summer. In fact, it is a large social event and there are long racks for hanging up the rugs once they have been rinsed. In winter, they are thrown into the snow, shaken down and then brought back inside. Not as socially satisfying, but still very effective.
Australia has the advantage of receiving long hours of sunlight, and ultraviolet light is a very effective sterilising agent. Put your rugs out into full sunlight and turn them over after a couple of hours. Then shake, beat or vacuum thoroughly. This should be done every three months or at the very least twice a year. You should also do it with your pillows and doonas. It is what our grandparents did, and is still an effective way of cleaning and sterilising our bedding. Low toxicity sanitising can also be useful if you can't get your mattress outside, but don't substitute a particle laden mattress with a chemical laden one.
Professional carpet cleaning should be done on all carpets every six to 12 months. However, as in every industry, there are contractors who are thorough and professional and those who do more harm than good. We have found that some carpet cleaners with very cheap rates leave behind more contaminants than were there prior to cleaning - and they damage the carpet as well. The money would have been better spent getting the job done properly. Thorough cleaning will increase the life of your carpet, not shorten it.
Using chemicals to clean carpets can have deleterious health effects. Chemical cleaners, fungicides and acaricide (a pesticide used to kill dust mites and their eggs) contain many toxins that can cause headaches and other health symptoms. Residues of these chemicals are left behind in the carpet and will also attach to respirable dust.
While we don't want to dwell on cleaning chemicals, we surveyed 425 homes and found that 16% of people who do the cleaning at home react to cleaning chemicals. The most frequent symptoms included skin complaints, irritation of the nose and throat and respiratory problems, including asthma. But perhaps of greatest concern was the fact that that the majority, 84%, thought chemicals did not pose a health risk and only 33% regularly read the labels and instructions! It was only those who were adversely affected who recognised a problem. This demonstrates today's prevalent attitude about chemicals: "If it's not affecting me now, it's OK."
This mindset was the downfall of an older lady who now reacts to many cleaning chemicals. In the past she thought people who complained of chemical sensitivities were "whiners," until she began to be affected herself. This woman has now been forced to make enormous changes in order to manage her own chemical sensitivities. Her understanding that many household cleaning agents contain toxic substances came at the price of her health.
Cleaning products contain a cocktail of chemicals. They should be used sparingly, if at all, and always stored in a safe place. Hundreds of children are poisoned each year by common cleaning agents. Mixing cleaning chemicals together is very hazardous. For example, mixing bleach with an ammonium disinfectant "to make it more effective" creates the very toxic chloramine and chlorine gas, which is a major cause of adult poisoning in the home. While most people recover during the 24 hours following exposure, some will suffer from life long health problems.
The most positive response in our survey was the fact that a large percentage of householders reported a willingness to spend more money for safer chemicals.
Another of our surveys revealed that the average home has 20 to 40 different cleaning agents. These can be reduced to six or less. Don't be seduced by advertisements that say you need more chemicals to clean effectively and hygienically. What did our grandparents use? Usually bicarb soda, borax, vinegar, soap and water. These simple, cheap and relatively nontoxic substances are still effective cleaning agents.
Dr Peter Dingle is a researcher, educator and public health advocate. He has a PhD in the field of environmental toxicology and is not a medical doctor.