Most people know that pollution can aggravate lung diseases like asthma, but the American Heart Association warns that polluted air — a toxic brew of carbon monoxide, ozone, lead, tobacco smoke, particulate matter and an array of other poisonous components — also raises your risk for heart attack and stroke. One easy and inexpensive way to cut this risk:Use a high efficiency particulate air (HEPA) filter in your home. These powerful filters, which were first developed to remove radioactive contaminants from nuclear facilities, can’t clean every pollutant from your home’s air (for example, they don’t remove carbon monoxide), but they do trap the tiny particles that other filters would miss — and now there’s no doubt that they can rapidly improve health.

Fewer Indoor Pollutants = Better Cardiovascular Health

Ryan Allen, PhD, assistant professor, Simon Fraser University in British Columbia, and his colleagues spent the last few years studying the impact of air pollution on residents’ heart health in a small rural community where wood-burning stoves are a major source of home heating… and the primary cause of pollution. Dr. Allen’s team installed portable HEPA filters in 25 tobacco-free homes of 45 adult residents. Thirteen homes had wood-burning stoves. The participants operated the HEPA devices for two seven-day periods — one in which their filters, made of special fibers, were in place and one in which they were not (so no pollutants were removed).

At the end of each seven-day period, the researchers collected air samples from each home and blood samples from each adult resident. To evaluate the health of endothelial cells that line the inside walls of blood vessels, researchers used a fingertip device to measure reactive hyperemia(a temporary increase in blood flow that follows a blood flow shortage). A low hyperemia index is an early sign of atherosclerosis — a buildup of waxy plaque inside blood vessels and hardening of blood vessels that can lead to heart attack or stroke.

In comparing results from the two periods (with and without air filters), investigators found that HEPA filters made a huge difference. Dr. Allen reports that HEPA use…

  • Reduced indoor air pollution by more than 50%. The level of average indoor pollutant particulates fell by 60% and wood smoke by 75%.
  • Improved blood vessel health. A 9.4% increase in the reactive hyperemia index suggested better blood vessel health and endothelial function.
  • Decreased systemic inflammation. Participants’ blood levels of C-reactive protein (CRP), an important marker of heart disease, dropped by 32.6% after one week of HEPA filtration.

Pollution causes inflammation in the lungs and blood vessels, including those that deliver blood to the heart and brain, Dr. Allen noted. When you subject your body to this kind of insult over and over, such as when you breathe polluted air week after week, the inflammation becomes chronic… damaging blood vessels and raising your risk for heart attack and stroke. This study shows that a simple intervention can improve indoor air quality and reduce pollution-related cardiovascular health risks.

Researchers’ findings appeared in the January 21, 2011, edition of the American Journal of Respiratory and Critical Care Medicine.

What to Look for in a Filter

The Department of Energy (DOE) has established strict standards for HEPA filters: They must remove at least 99.97% of airborne particles 0.3 micrometers or larger — a particle that size is far too small for the human eye to see (nearly 100,000 of them would be needed to span the diameter of a quarter). That’s why these filters can make quick work of most of your air’s dust, pollen, mold, carcinogens and irritants from smoke or vehicle emissions. A good HEPA room unit costs about $200. Here’s what to look for…

  • Make sure that it’s a true HEPA filter. Beware of look-alike products labeled HEPA-type, HEPA-like or 99% HEPA. These may not meet DOE requirements. A true HEPA filter will have a serial number and list the test results (i.e., that it traps at least 99.97% of 0.3 micrometer particles).
  • Buy the right size. Purchase a unit that is appropriate for the size of the room it will be used in, and be sure to have units covering the rooms where you spend the most time, such as bedrooms and the living/TV room. Replace filters regularly. Even if the owner’s manual recommendation is for every two to three years, yearly replacement of filter elements ensures that your unit will operate efficiently.
  • Get a prefilter, too. In addition, most HEPA units come with prefilters, which remove larger particles so they do not clog finer internal filters.
  • There are many qualifying brands, including Whirlpool, Hunter and GE.
  • If you have forced-air heating, consider a house-wide filtration system, such as those made by Fantech http://Residential.Fantech.net/residential-products/indoor-air-quality/hepa/, rather than investing in separate units for each room. These house-wide systems are fitted to your existing ductwork. Cost: Approximately $500 for the unit (installation costs are separate and vary according to where you live).

About that noise…

Unfortunately, there is one downside to portable HEPA filters — they’re noisy. They contain strong fans that force air through the system to effectively filter it. One way around this is to run filters on medium or high when you are not home and turn them down to low when you are home. A house-wide system connected to your ductwork will create less noise in your living areas.