Dec 26

Indoor Air Pollutiuon Facts: What is Indoor Air Pollution and How to Reduce it

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Indoor Air Pollution Facts: What is Indoor Air Pollution and How to Reduce it How is the Air Quality in your Home?

Indoor air pollution facts, what is indoor air pollution we ask? We typically don’t think our homes have air quality problems, as we cannot see it for the most part. It isn’t like we have billowing plumes of smoke coming out of our vents or floorboards, at least not in the sense like those which we see outdoors and are easily identifiable. This is why it is difficult to realize we may have a problem and what to do about it. Once we know the sources of our problems, then we can take steps to correct or minimize those problems and find solutions to clean the air, possibly with air cleaners, so to speak and make our homes into healthier environments for us and our families and loved ones.

Indoor air pollution has been described by the EPA and Congress as America’s number one environmental health problem and indoor air pollution can be four to five times worse than outdoor air and even greater. The Department of Consumer Affairs states that children and the elderly are the ones most affected by polluted indoor air.

We spend about 90% of our time indoors and all this gets breathed into us and our children. Air pollutants can and do cause allergies, sick building syndrome, bacterial infections and spread viruses to name a few. The American College of Allergists state that 50% of all illnesses are caused by polluted indoor air. They state that 10 to 12 million people in the US suffer from asthma and that asthma is the single largest cause of hospital visits by children.

Indoors and Outdoors Air Pollution Health Risks Chart

Indoors and Outdoors Air Pollution Health Risks Chart

The World Health Organization states that 40% of all buildings pose a serious health hazard due to poor indoor air quality. IAQ experts consider a building to be “sick” when there are known contaminants at harmful concentrations or when 20% or more of its occupants are plagued by a variety of common symptoms that occur only while at work.

These questions lead us to ask how does our air inside the house get polluted? Much can be said about proper ventilation, for if we don’t have enough fresh air entering the home, then pollutants can accumulate to levels which can pose immediate health problems and affect our comfort.

Unless homes are built with a special mechanical means of ventilation, homes that are designed and constructed to minimize the amount of outdoor air that can “leak” into and out of the home may have higher pollutant levels than other homes. However, because some weather conditions can drastically reduce the amount of outdoor air that enters a home, pollutants can build up even in homes that are normally considered “leaky”.

How Does Outdoor Air Enter a House?

Indoor Air Quality Causes

Indoor Air Quality Causes

Outdoor air enters and leaves a house by either infiltration, natural ventilation, and/or mechanical ventilation. In a process known as infiltration, outdoor air flows into the house through openings, joints, and cracks in walls, floors, and ceilings, and around windows and doors. In natural ventilation, air moves through opened windows and doors. Air movement associated with infiltration and natural ventilation is caused by air temperature differences between indoors and outdoors and by wind. Finally, there are a number of mechanical ventilation devices, from outdoor-vented fans that intermittently remove air from a single room, such as bathrooms and kitchen, to air handling systems that use fans and duct work to continuously remove indoor air and distribute filtered and conditioned outdoor air to strategic points throughout the house. The rate at which outdoor air replaces indoor air is described as the air exchange rate. When there is little infiltration, natural ventilation, or mechanical ventilation, the air exchange rate is low and pollutant levels can increase to unhealthy levels. One common way to reduce these unhealthy levels is with air cleaners, which we examine in depth later.

What is Indoor Air Pollution?

What Causes Indoor Air Problems?

Indoor Air Quality Concerns

Indoor Air Quality Concerns

Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air quality problems in homes. Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the home. High temperature and humidity levels can also increase concentrations of some pollutants.
Pollutant Sources

There are many sources of indoor air pollution in any home. These include combustion sources such as oil, gas, kerosene, coal, wood, and tobacco products; building materials and furnishings as diverse as deteriorated, asbestos-containing insulation, wet or damp carpet, and cabinetry or furniture made of certain pressed wood products; products for household cleaning and maintenance, personal care, or hobbies; central heating and cooling systems and humidification devices; and outdoor sources such as radon, pesticides, and outdoor air pollution.

The relative importance of any single source depends on how much of a given pollutant it emits and how hazardous those emissions are. In some cases, factors such as how old the source is and whether it is properly maintained are significant. For example, an improperly adjusted gas stove can emit significantly more carbon monoxide than one that is properly adjusted.

Indoor Air Quality Problems

Indoor Air Quality Problems

Some sources, such as building materials, furnishings, and household products like air fresheners, release pollutants more or less continuously. Other sources, related to activities carried out in the home, release pollutants intermittently. These include smoking, the use of unventilated or malfunctioning stoves, furnaces, or space heaters, the use of solvents in cleaning and hobby activities, the use of paint strippers in redecorating activities, and the use of cleaning products and pesticides in house-keeping. High pollutant concentrations can remain in the air for long periods after some of these activities.

Indoor Air Pollution

How Indoor Air Quality Affects our Health

Health effects from indoor air pollutants may be experienced soon after exposure or, possibly, years later.

Immediate effects

Indoor Pollution Danger Levels Chart

Indoor Pollution Danger Levels Chart

Immediate effects may show up after a single exposure or repeated exposures. These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Such immediate effects are usually short-term and treatable. Sometimes the treatment is simply eliminating the person’s exposure to the source of the pollution, if it can be identified. Symptoms of some diseases, including asthma, hypersensitivity pneumonitis, and humidifier fever, may also show up soon after exposure to some indoor air pollutants.

The likelihood of immediate reactions to indoor air pollutants depends on several factors. Age and preexisting medical conditions are two important influences. In other cases, whether a person reacts to a pollutant depends on individual sensitivity, which varies tremendously from person to person. Some people can become sensitized to biological pollutants after repeated exposures, and it appears that some people can become sensitized to chemical pollutants as well.

Cigarette smoke not good for indoor air quality - air cleaners can help with this

Cigarette smoke not good for indoor air quality - air cleaners can help with this

Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution. For this reason, it is important to pay attention to the time and place symptoms occur. If the symptoms fade or go away when a person is away from home, for example, an effort should be made to identify indoor air sources that may be possible causes. Some effects may be made worse by an inadequate supply of outdoor air or from the heating, cooling, or humidity conditions prevalent in the home.

Long-term Health Effects

Other health effects may show up either years after exposure has occurred or only after long or repeated periods of exposure. These effects, which include some respiratory diseases, heart disease, and cancer, can be severely debilitating or fatal. It is prudent to try to improve the indoor air quality in your home even if symptoms are not noticeable.

While pollutants commonly found in indoor air are responsible for many harmful effects, there is considerable uncertainty about what concentrations or periods of exposure are necessary to produce specific health problems. People also react very differently to exposure to indoor air pollutants. Further research is needed to better understand which health effects occur after exposure to the average pollutant concentrations found in homes and which occurs from the higher concentrations that occur for short periods of time.

Indoor Air Pollution and Pets

What if this was inside your home? Air cleaners would not even help this toxic air pollution

What if this was inside your home? Air cleaners would not even help this toxic air pollution

While many of the sources on this topic cover a good deal of information, they neglect to point out that it can also affect our pets health if we have any, not to mention the fact that they themselves (pets) can cause indoor air quality problems. While we want our pets to be happy and healthy, we also want the same for ourselves, so to reduce the pets influence on our indoor environment, you should clean your pet cages, litter boxes, bedding and other areas they frequently rest often. The areas where your pets sleep and rest will need frequent cleaning to avoid creating large deposits of pet hair and pet dander, prevent the pet hair and pet dander from being re-released into the air, and to reduce pet odors. Pet cages and their bedding can hold large accumulations of hair and dander, so they should be cleaned frequently to remove as much hair and dander as possible. It is important to choose bedding items for the pet that can be washed in a washing machine to make cleaning these items as simple as possible.

We also find it amazing how much people can love their pets and what they will do for them. This is further proven by pet owners with asthma and allergies who would rather take drugs and risk the side affects than to part with their beloved furry friends. However, as much as we pet owners love them, pets can contribute to indoor air quality problems in two ways; by shedding dander, and by relieving themselves indoors, whether by accident, or by designation, such as in a litter box which we previously mentioned.

Indoor Air Pollution Family wearing gas masks

Indoor Air Pollution Family wearing gas masks

Now, despite the fact that most pet owners would never believe that their beloved pet would urinate indoors, it happens everyday. Not only can the odors of pet waste be offensive, but it can affect the indoor air quality and the health of all those that live in the home. In order to eliminate unhealthy conditions, one must understand how pets and pet waste can become a health problem to us, and to themselves.

Pets by nature do their duty outdoors, where there is no harm done as it breaks down quickly and gasses dissipate quickly into the air, and doesn’t create any issues, except for maybe when you step in it by accident. However, in our closed in homes, without proper air cleaners, it is an entirely different story. We have sealed out nature’s goodness, disallowing natural purification of our indoor air. If you have pets living indoors, then you have a need for serious attention to indoor air purification and filtration measures, along with diligent cleaning.

Bird and rodent cages, cat boxes, pet accidents, and shedding contaminates the air we breathe indoors. This can cause allergies, asthma, and other indoor air related illnesses. The contaminants can consist of airborne fecal and dried urine particles, animal dander, and chemical gasses from metabolism which are recognized as “pet odors”. Indeed, if we are to have animals living indoors, we need to follow specific strategies to prevent unhealthy living conditions for both humans and pets, and one typical, useful way is to use air cleaners, however we can also use House Plants That Clean the Air if you are so inclined.

Identifying Air Quality Problems

Household Air pollution sources

Household Air pollution sources

Some health effects can be useful indicators of an indoor air quality problem, especially if they appear after a person moves to a new residence, remodels or refurnishes a home, or treats a home with pesticides. If you think that you have symptoms that may be related to your home environment, discuss them with your doctor or your local health department to see if they could be caused by indoor air pollution. You may also want to consult a board-certified allergist or an occupational medicine specialist for answers to your questions.

Another way to judge whether your home has or could develop indoor air problems is to identify potential sources of indoor air pollution. Although the presence of such sources does not necessarily mean that you have an indoor air quality problem, being aware of the type and number of potential sources is an important step toward assessing the air quality in your home.

A third way to decide whether your home may have poor indoor air quality is to look at your lifestyle and activities. Human activities can be significant sources of indoor air pollution. Finally, look for signs of problems with the ventilation in your home. Signs that can indicate your home may not have enough ventilation include moisture condensation on windows or walls, smelly or stuffy air, dirty central heating and air cooling equipment, and areas where books, shoes, or other items become moldy. To detect odors in your home, step outside for a few minutes, and then upon reentering your home, note whether odors are noticeable.

Improving the Air Quality in Your Home

Indoor Air and Your Health

Reducing Indoor Air Pollution: Three Basic Strategies

Indoor Air Pollution Source Control – Air Quality

Air cleaners can eliminate many of these common household pollutants shown here

Air cleaners can eliminate many of these common household pollutants shown here

Usually the most effective way to improve indoor air quality is to eliminate individual sources of air pollution or to reduce their emissions. Some sources, like those that contain asbestos, can be sealed or enclosed; others, like gas stoves, can be adjusted to decrease the amount of emissions. In many cases, source control for air quality is also a more cost-efficient approach to protecting indoor air quality than increasing ventilation because increasing ventilation can increase energy costs. Specific sources of indoor air pollution in your home are listed later in this section.

Ventilation Improvements – Air Cleaners

Don't have a smoking house like this one giving off air pollution, use air cleaners or plants to keep your home healthy!

Don't have a smoking house like this one giving off air pollution, use air cleaners or plants to keep your home healthy!

Another approach to lowering the concentrations of indoor air pollutants in your home is to increase the amount of outdoor air coming indoors. Most home heating and cooling systems, including forced air heating systems, do not mechanically bring fresh air into the house. Opening windows and doors, operating window or attic fans, when the weather permits, or running a window air conditioner with the vent control open increases the outdoor ventilation rate and serves as a simple form of air cleaners, however it is not a substitute for a commercial model. Local bathroom or kitchen fans that exhaust outdoors remove contaminants directly from the room where the fan is located and also increase the outdoor air ventilation rate.

It is particularly important to take as many of these steps as possible while you are involved in short-term activities that can generate high levels of pollutants–for example, painting, paint stripping, heating with kerosene heaters, cooking, or engaging in maintenance and hobby activities such as welding, soldering, sanding, model making and gluing. You might also choose to do some of these activities outdoors, if you can and if the weather cooperates.

Advanced designs of new homes are starting to feature newer mechanical systems that bring outdoor air into the home, serving as air cleaners which can reduce air pollution are increase air quality. Some of these designs include energy-efficient heat recovery ventilators (also known as air-to-air heat exchangers). Read the U.S. Department of Energy’s “Improving the Efficiency of Your Duct System” at US Dept. of Energy: Building America.

Using air cleaners can help reduce air pollution in your home!

Using air cleaners can help reduce air pollution in your home!

There are many types and sizes of air cleaners on the market, ranging from relatively inexpensive table-top models to sophisticated and expensive whole-house systems. Some air cleaners are highly effective at particle removal, while others, including most table-top models, are much less so. Air cleaners are generally not designed to remove gaseous pollutants.

The effectiveness of air cleaners depends on how well it collects pollutants from indoor air (expressed as a percentage efficiency rate) and how much air it draws through the cleaning or filtering element (expressed in cubic feet per minute). A very efficient collector with a low air-circulation rate will not be effective, nor will a cleaner with a high air-circulation rate but a less efficient collector. The long-term performance of any air cleaners depends on maintaining it according to the manufacturer’s directions.

Another important factor in determining the effectiveness of air cleaners are the strength of the pollutant source. Table-top air cleaners, in particular, may not remove satisfactory amounts of pollutants from strong nearby sources. People with a sensitivity to particular sources may find that air cleaners are helpful only in conjunction with concerted efforts to remove the source.

Over the past few years, there has been some publicity suggesting that houseplants have been shown to reduce levels of some chemicals in laboratory experiments and serve as air cleaners. There is currently no evidence, however, that a reasonable number of houseplants remove significant quantities of pollutants in homes and offices. Indoor houseplants should not be over-watered because overly damp soil may promote the growth of microorganisms which can affect allergic individuals.

Indoor Air Cleaners

Indoor Air Cleaners

At present, EPA does not recommend using air cleaners to reduce levels of radon and its decay products. The effectiveness of these devices is uncertain because they only partially remove the radon decay products and do not diminish the amount of radon entering the home. EPA plans to do additional research on whether air cleaners are, or could become, a reliable means of reducing the health risk from radon. EPA’s booklet, Residential Air Cleaners, provides further information on air-cleaning devices to reduce indoor air pollutants.

For most indoor air quality problems in the home, source control is the most effective solution. This section takes a source-by-source look at the most common indoor air pollutants, their potential health effects, and ways to reduce levels in the home. (For a summary of the points made in this section, see the section entitled “Reference Guide to Major Indoor Air Pollutants in the Home”).

Ozone Generators That Are Sold As Air Cleaners (which is only available via this website) was prepared by EPA to provide accurate information regarding the use of ozone-generating devices in indoor occupied spaces. This information is based on the most credible scientific evidence currently available.

Should You Have the Air Ducts in Your Home Cleaned?” was prepared by EPA to assist consumers in answering this often confusing question. The document explains what air duct cleaning is, provides guidance to help consumers decide whether to have the service performed in their home, and provides helpful information for choosing a duct cleaner, determining if duct cleaning was done properly, and how to prevent contamination of air ducts.


We can reduce the effects of indoor air pollution when we know what is indoor air pollution, and look into Air Cleaners to help reduce, if not eliminate this common household problem. Peace my friends!

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