Ways to improve indoor air quality in your home may not be your first thought when you have watery eyes and a runny nose. After all, those are typical symptoms of suffering with allergies or a cold.
But poor indoor air quality could also be to blame. Problems with indoor air quality (IAQ) can lead to immediate effects such as irritation of the eyes, nose and throat, as well as headaches, dizziness, shortness of breath, nausea and fatigue. The long-term effects can be serious, so it’s not an issue to ignore.
Fortunately, there are ways to improve air quality in your home, including air filters, a wide variety of portable air purifiers, proper maintenance of your heating, and annual tune-ups for your air conditioning systems.
What Is Indoor Air Quality?
In simplest terms, indoor air quality describes the quality of the air in your home. But IAQ is actually an official term used by the Environmental Protection Agency, which defines IAQ as the “air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants.” The EPA ranks indoor air pollution among the top five environmental risks to public health.
The air inside many homes is far less clean than outside air. Homes built since 1979 are better sealed to make them more energy efficient, but that’s a two-edged sword. Because energy-efficient homes are “tighter” they keep more contaminants and moisture inside – which makes a high-efficiency air conditioning and heating system essential for comfort and safety.
On average, Americans spend about 90% of the time indoors, where concentrations of some pollutants are two-to-five times higher than outside. Children are especially sensitive to indoor air quality problems. Children breather faster, so they inhale 50% more air per pound of bodyweight than adults.
The quality of the air includes a lot of factors, such as temperature, humidity, and ventilation, as well as the presence of mold and other contaminants. The EPA has established standards and guidelines for IAQ, but we’ll get to those later because they are less relevant to a typical homeowner than what the most common pollutants are and what can be done to reduce or eliminate them.
So let’s start with the pollutants that can affect your health both now and in the future.
What Are the Most Common Indoor Pollutants?
The list of the potential indoor pollutants is long because there are so many pollutants in the world outside your home. But this is meant to be informative, not scary, so we’re only going to go through the most common indoor pollutants.
Also, after the description of each pollutant, we’ll show ways you can reduce or eliminate them in your home to improve the quality of the air you breathe:
Some types of mold, which are fungi that grow both indoors and outdoors, are harmless. Others are dangerous and can trigger allergic reactions and asthma attacks. There are more than 400,000 types of molds, which can fit into one of three categories – allergenic, pathogenic and toxic.
Allergenic molds in small quantities may not be harmful but they can make you feel bad, depending on your tolerance. Aspergillus is a common allergenic mold that can cause watery eyes, coughing, runny nose, postnasal drip and shortness of breath.
Pathogenic molds are more problematic because they can attack a healthy immune system and cause infections in humans. They can cause molds and fungi to grow in your body, which can lead to serious medical conditions. Cryptococcus neoformans is one of the most common pathogenic molds affecting indoor air quality worldwide.
“Toxic” molds are the most dangerous. While the molds themselves are not toxic, they release chemicals called mycotoxins into the air that are toxic. Stachybotrys chartarum, commonly known as black mold, grows readily in areas of excessive moisture, water leaks, condensation. It thrives on fiberboard, gypsum board, paper, dust, and lint.
- Ways to reduce or eliminate mold: Mold thrives in warm, moist environments, so keeping the humidity levels in your home down is key. Most homes have a central air conditioner that pulls humidity from the air, but many older and under-sized systems cannot remove humidity fast enough, which allows mold to grow in HVAC ducts, grates and air handlers. It’s also important to make sure you clean up water spills and that your home doesn’t have water leaks. Damp environments are breeding grounds for mold.
2. Carbon Monoxide and Nitrogen Dioxide
Carbon Monoxide and Nitrogen Dioxide aren’t the same, but we’ll group them together because they are both toxic gases that can be dangerous in the home.
Exposure to carbon monoxide can cause headaches, dizziness, nausea and confusion, and at high enough levels, it can be fatal. Nitrogen dioxide isn’t quite as dangerous, but even low levels can cause irritation to the eyes, nose, and throat. Higher levels of exposure can cause chronic bronchitis and lung injury and is especially dangerous for children and asthmatics. Carbon monoxide detectors like the one shown here are inexpensive and easy to use – many plug directly into a wall socket.
- How to avoid CO and NO2 problems: Have your heating systems checked annually by a licensed heating and cooling professional. The safety of combustion appliances, such as heaters, begins with a correct installation that allows proper ventilation around the unit. A licensed professional can ensure that the installation is done right.
3. Biological Contaminants
We already talked about mold, but it’s part of the broad category of biological contaminants that include bacteria, viruses, dust, animal dander, mites, pollen, and insects. Poor indoor air quality is often attributed to these biological contaminants from a variety of sources, such as people, animals, plants, and even contaminated central air conditioners.
How to reduce biological contaminants: General cleaning of a home is important, including the cleanup of spills and drying of damp areas. Ventilation and good air distribution also help prevent the growth and spread of biological contaminants. As mentioned above, contaminated central AC units can add to the problem by becoming breeding grounds for mold and mildew and distributing contaminants throughout the home. That’s why it’s important to properly maintain heating and air conditioning systems and have an AC professional inspect them at least once per year.
4. Volatile Organic Compounds
Volatile Organic Compounds (also known as VOCs) include a variety of chemicals that are ingredients in household products such as paints and varnishes, cleaners, disinfectants, cosmetics, aerosol sprays, and air fresheners. VOCs can release organic compounds when being used, or simply when being stored, and can cause eye, nose and throat irritation in the short term. According to the EPA, they can also have other health effects including headaches and loss of coordination and nausea, and they can cause damage to the liver, kidneys and central nervous system.
- Ways to protect your health from VOCs: It’s important to increase ventilation in your home when using products with VOCs and carefully follow the instructions on the product’s label. Additionally, don’t store open containers of unused paints inside your home, and try to buy products with VOCs in small amounts that will be used in the near future.
Radon is odorless and colorless and it’s found naturally in the environment – but at levels that are safe for humans. Radon is emitted from the earth, and when it gets trapped inside a home, either through joints in walls, the foundation or another opening, it can sometimes concentrate inside a home. The American Lung Association states that about 1 in every 15 homes has dangerously elevated radon levels.
Exposure to elevated levels of radon increases your risk of lung cancer. According to the National Cancer Institute, radon is the second-leading cause of lung cancer in the United States (cigarette smoking is number one).
- Ways to protect your home: A home radon screening can be performed by a qualified professional, and do-it-yourself radon screening kits can be purchased. But if your home has elevated levels of radon, removing it is not a do-it-yourself job. A qualified professional can do the job and provide safe indoor air quality.
Some Other Potential Contaminants
Secondhand smoke: This smoke van cause eye, nose and throat irritation, and over time, it has been shown to cause many of the same health effects as smoking, including bronchitis and lung cancer.
Pesticides: Research by the Environmental Protection Agency has shown that pesticide residue is widespread in U.S. homes. Repeated exposure to pesticides has been linked to cancer, so it’s important to limit the use of pesticides, limit their quantities, follow manufacturer’s directions and make sure they are used in a well-ventilated area.
Lead particles and asbestos: The use of lead in paints was banned in America more than 40 years ago, and most uses of asbestos were banned in 1989. But if you live in an older home, it’s important to know if any lead-based paint remains or asbestos was among the building materials used. Exposure to asbestos has been linked to mesothelioma and lung cancer and the ingestion of lead paint, which can including breathing in the dust of deteriorating lead paint, has been shown to have serious health effects.
Types of Indoor Air Quality Equipment for Homes
Now that we’ve covered the contaminants, let’s get into the ways you can improve your home’s indoor air quality. In addition to removing pollutant sources and making sure your home is well ventilated, there are products that can improve IAQ.
1. Air Filters
HVAC systems and furnaces have air filters that keep dust and debris out of the blower motors and can reduce the presence of larger air particles, such as lint, dirt and hair. It’s important to check your air filters at least every three months and replace them when they are dirty. Newer HVAC systems generally use 4-inch filters instead of the older-style 1-inich thick filters. The thicker the filter the more fabric it has to trap particles.
Air filters vary in quality and price, and their ability to filter particles from the air is shown in their MERV rating (Minimum Efficiency Reporting Value), which ranges from a low of one to a high of 16. The EPA recommends using the highest-rated filter that fits your HVAC system fan and filter slot. The higher the rating, the more pollutants a filter removes from the air.
If your system is not designed to use high-efficiency air filters (MERV 13-16) they will restrict airflow, making the HVAC system less efficient; it will run more often and wear out sooner. These filters, known as HEPA (high-efficiency particulate arrestance) can clean the air of particles as small as 0.3 microns. For reference, a micron is millionth of a meter or 1/25,400th of an inch!
The tricky part of comparing filters is that not all manufacturers use the MERV system. 3M’s Filtrete HEPA filters are rated on 3M’s proprietary Microparticle Performance Rating (MPR) scale. Not to be left out, Home Depot has its own proprietary rating system for products it sells, called Filter Performance Rating (FPR).
Products labels should provide a means to compare using different rating systems, but in case not, there is a useful MERV/MPR/FPR equivalency chart in this article. Always follow manufacturers’ recommendations for the equipment installed in your home.
2. Air Purifiers
Air purifiers, also referred to as air cleaners, operate in addition to HVAC filters. They may be freestanding units that serve a room or part of a home, or they may be whole-house units that connect to your central HVAC system. Air purifiers employ a variety of technologies to get to the same result of improved indoor air quality.
- HEPA Purifiers: these purifiers use high-efficiency HEPA filters to clean the air. HEPA filters have been around for many years and have been proven effective. Because they soak up so much contamination from the air, filters must be changed frequently, as often as monthly.
- UV Purifiers: UV (Ultraviolet) purifiers use electromagnetic radiation to kill bacteria and reduce issues with mold and viruses. UV purifiers, however, are not effective at filtering out allergens, dust, cigarette smoke and gases.
- Ionic Purifiers: An ionic generator sends out negatively charged ions that attract allergens, airborne dust and other positively charged particles. Ionic purifiers are effective at removing secondhand smoke, but they also produce ozone, which is a pollutant (see more under Ozone Air Purifiers below).
- Carbon Filter Purifiers: These purifiers have carbon or charcoal that is activated, meaning it has been treated with oxygen. That makes the carbon very porous, allowing it to absorb airborne particles and gases. Carbon filter purifiers are especially effective at removing odors in a room.
- Ozone Air Purifiers: These purifiers, which work by emitting ozone into your home’s air, are good at killing mold and mildew. However, although ozone in the atmosphere is essential protecting the earth from solar radiation, it’s a pollutant at ground level. The EPA uses the phrase “good up high, bad nearby” to describe ozone.
3. Whole House Air Cleaners
For many homeowners, a whole-house air cleaning system is a great alternative to having a collection of special-purpose devices scattered throughout the house to improve indoor air quality.
Whole-house air purifiers usually incorporate two or more of the technologies described above to produce remarkable results. For example, the TRANE CleanEffects whole-house air filtration system uses a three-step process:
- a pre-filter that traps larger particles,
- a second stage that puts a positive electrical charge on the remaining particles that pass through it, followed by
- negatively-charged, reusable collector cells that attract and trap the smaller, positively-charged contaminants.
The CleanEffects eliminates suspended particles down to 0.1 microns. This whole-house air purifier is about the same size as a filter box for a 4-inch HVAC filter. Because the collector cells are reusable you don’t have to worry about dealing with confusing comparisons or replacing filters. Many homeowners who have these systems tell us they never have to dust. Here’s a cutaway view and a video that shows how the CleanEffects works.
Can Houseplants Help Improve Indoor Air Quality?
The impact of houseplants on IAQ is the subject of some debate. Through photosynthesis, plants convert carbon dioxide into oxygen and can remove toxins from the air, but there’s little scientific evidence that they can clean enough air in a home to significantly affect indoor air quality.
Houseplants have been shown to have other positive effects, including reducing stress, but they can’t make a big contribution to indoor air quality. In addition, plants can attract insects such as aphids, whiteflies, thrips, and mealybugs.
Similarly, some people like to burn candles to give the air a clean smell or favorite scent. The pleasing aroma may only mask the pollutants the candles introduce. The flame of any candle produces sulfur pollution. Researchers at the University of South Carolina found that the most prevalent type, petroleum-based paraffin candles, introduce other toxic chemicals to the air, including toluene and benzene.
What If the Air in Your Home is Too Dry?
While excessive humidity in a home can have serious consequences, excessively dry air also makes for poor indoor air quality. Repeated heating cycles in cold weather reduce airborne moisture substantially, which can adversely affect your health and damage your home and furnishings.
Breathing excessively dry air causes the fluids that coat nasal passages, throat, and lungs to thin out and provide less protection against airborne contaminants. You know the symptoms – coughing, wheezing, runny nose, sore throat and more. Wood furniture and flooring can dry out and crack.
Most homes have a room humidifier or two somewhere, which can bring the humidity up to comfortable levels. A whole-house humidifier integrated with your HVAC system sets humidity at comfortable levels throughout the house. Whole-house humidifiers can be added to most existing HVAC systems.
Is There an Established Standard for Indoor Air Quality?
The Environmental Protection Agency has established standards and guidelines, but they read like a complicated user’s manual in describing things like particulate matter and polycyclic aromatic hydrocarbons. (Yes, polycyclic aromatic hydrocarbons).
The more important part of the EPA’s guidelines, at least for most of us, are the general tips about buying low-VOC products, emphasizing good ventilation systems and using effective air filters.
Will Replacing My Central Air Conditioning Help Indoor Air Quality?
The air you breathe in your home is outside air filtered through your HVAC system, which maintains a consistent temperature and humidity level to maximize comfort. Installing a new air conditioning system will improve indoor air quality, but if your unit is working properly and has been properly maintained, the IAQ improvement won’t be significant enough to be worth the cost.
However, replacing an older air conditioning unit provides many benefits, including the technological breakthroughs that have made new HVAC units more energy-efficient, less expensive to operate, better at controlling the comfort level in homes — including humidity – and more environmentally friendly. And yes, the new HVAC system will help the indoor air quality.
Considering we spend about 90 percent of our lives indoors, it’s important that we recognize the potential contaminants and consider the ways that we can improve indoor air quality.
Contaminants include toxic biological contaminants (including mold) and toxic gases, as well as the volatile organic compounds found in common household items such as paints, glues, cleaners and air fresheners. Keeping your home well-ventilated can help reduce these pollutants, along with air filters in your HVAC system and portable air purifiers.
Keeping your air conditioning system maintained is also an easy way to improve your home’s air quality. An AC professional can inspect your heating and air conditioning systems to make sure they are working properly and helping filter the outside air that becomes the air you breathe inside your home.
These ways to improve indoor air quality will help ensure that the air in your home will keep you both comfortable and healthy.