Indoor Air Quality and Cardiovascular Disease

According to the US EPA, the air inside your home or office is often times several times more polluted than outside air. Although scientists have known for some time that air pollution leads to an increased risk of cardiovascular disease (the number one killer in America), recent research appearing in the "American Journal of Respiratory and Critical Care Medicine" is the first study of its type to investigate the link with indoor air. The results of this research will not only surprise you, they'll point out something you can do right now to help protect yourself and your family.

The Details of the Study

To perform their research, a team of scientists from Sweden and Denmark looked at the affect of tiny particles on endothelial cells. Endothelial cells line the interior surfaces of all blood vessels as well as the heart, and support blood flow by performing a number of important functions including reducing friction (and thereby reducing the work load on your heart). A reduction in the Microvascular Function (MVF) of endothelial cells through inflammation or other types of stresses can lead to a number of cardiovascular diseases including atherosclerosis.

Why study "tiny particles?" Because a significant portion of air pollution is made up of "particulates," tiny particles that are found in auto and diesel exhaust, cigarette or other types of smoke, and industrial stack emissions. These tiny particles are microscopic in size and are easily inhaled into the lungs where they enter the blood stream and contact the endothelial lining.

The study was a randomized, double blind study performed on 21 nonsmoking couples aged 60 to 75. All participants were in good health and all lived near busy roads meaning that they were routinely exposed to road dust as well as auto and diesel exhaust. The couples were studied in their homes and were randomly selected to be exposed to filtered air followed by non-filtered air, or the other way around while the scientists measured the amount and chemical properties of the particulates in the air. After every test, the Microvascular Function (MVF) of each individual was measured.

The Results and Conclusions

Once the research was concluded, some of the more significant results showed that:

* Filtering the indoor air improved MVF by more than 8%. This is pretty significant and is something any of us can achieve by following some of the recommendations listed below.

* The diameter of the airborne particulates and their mass, had a greater effect than their total number concentration. In other words, the smallest particles (smaller than 2.5 micrometers) were the biggest hazard, mainly because these particulates are too small to be caught by the body's natural defense systems and can easily enter the lungs and blood stream.

* MVF was also significantly linked to being exposed to particulates containing iron, potassium, copper, zinc, arsenic, and lead. This is important to those of us that happen to live near industrial or manufacturing plants.

Based on their results, the scientists concluded that,"Reduction of particle exposure by filtration of recirculated indoor air for only 48 hours improved MVF in healthy elderly citizens, suggesting that this may be a feasible way of reducing the risk of cardiovascular disease."

The Limitations of the Study

It's important to note some of the limits of the study in order to get a more balanced view of the results. First, note that all of the participants were in an age group (60 to 75) that is particularly susceptible to respiratory and cardiovascular disease to begin with. However, this does not mean that everyone else is immune.

According to the US EPA, the people that are most at risk from particulates, mold, or other respirable hazards include:

1. Young children and babies (their respiratory and immune system is still developing)

2. The elderly (their respiratory and immune system is not as efficient as it used to be)

3. The sick or immune compromised (their respiratory and immune system is already under attack)

4. People with underlying respiratory disease such as asthma or severe allergies.

Secondly, this study only looked at the effect of particulates on the cardiovascular system so it was a very narrow study. The study did not include other common factors that also affect Indoor Air Quality such as allergens, dust, pet dander, dust mites, mold, temperature and humidity, to name a few.

What This Means to You

Although it's true that this particular research focused on the elderly (aged 60 to 75), I personally believe that the results apply to all of us to some extent or another. The extent that you are affected by particulates is going to depend on your age, your genetic makeup, your over all health and fitness level, your work and living conditions, and so on. Most of these you can't do anything about. However, there is one factor you have some degree of control over: the amount of particulates in your home. Fortunately, there are a number of easy ways to reduce the amount of small particles floating around in your indoor air.

Reducing Particulates in Your Home

A couple of easy ways to reduce the amount of airborne particulates in your home include:

1. Purchase an air purifier for the bedroom(s). Where do you spend 7 to 9 hours of your time per night? In the bedroom. Consider purchasing a high quality air purifier for your bedroom(s). I recommend (and own) the purifiers distributed by Nikken, Inc. A word of warning though, they're pretty expensive but they're the best I've found. They're only sold by "Wellness Consultants" (email me for the one I use). Regardless of where or what kind of air purifier you buy, make absolutely sure that it does not produce ozone. Ozone is a toxic gas that can cause a number of health problems (see EPA warning at the EPA website listed below). You're trying to reduce indoor pollutants, not add to them.

2. Reduce airborne particulates by cleaning often. Purchase or make sure you have a vacuum with a HEPA filter on the exhaust. "HEPA" is a type of filter (not a brand name) and it stands for "High Efficiency Particulate Air." A HEPA filter will filter out a minimum of 99.97% of all particles 0.3 micros or larger. If you use a vacuum without a HEPA filter, all you're doing is recirculating particulates in the air instead of actually removing them.

3. Change and/or Upgrade the filters on your HVAC. Your HVAC filters are your front-line defense in removing particulates from the air inside your home. The US EPA recommends using a filter with at least a MERV 8 rating. "MERV' stands for "Minimum Efficiency Reporting Value" as determined by the American Society of Heating, Refrigeration and Air Conditioning Engineers. I personally recommend filters with a MERV 11 but only if you have a relatively new HVAC unit (less than 10 years old). You'll pay more but they'll remove smaller particulates from the air. If you have an older or less powerful HVAC unit, then a MERV 8 should suffice. In either case, change the filters according to the manufacturers recommendations (or more frequently if you live in a dusty area).

4. Consider reducing the amount of installed carpeting in your home and replacing it with wood or tile flooring. In the Indoor Air Quality business, installed carpeting is known as a "pollutant sink." The carpet fibers trap all kinds of dirt and gunk which it then releases back into the air every time it's disturbed. If you've ever pulled up old carpet, you were probably surprised (and disgusted) at how much dirt was underneath — even though you vacuum on a regular basis. Wood or tile floors are much easier to keep clean and you can still use the occasional throw rug.

Finally, remember that there is no "magic bullet" when it comes to improving Indoor Air Quality. However, the steps mentioned here will go a long ways towards reducing the number of particulates in your home or office and reducing your risk of cardiovascular disease.

Sources

For the full article, see "Indoor Particles Affect Vascular Function in the Aged: An Air Filtration-based Intervention Study" by Elvira Vaclavik Bräuner, Lykke Forchhammer, Peter Møller, Lars Barregard, Lars Gunnarsen, Alireza Afshari, Peter Wåhlin, Marianne Glasius, Lars Ove Dragsted, Samar Basu, Ole Raaschou-Nielsen, and Steffen Loft. Published in the "American Journal of Respiratory and Critical Care Medicine," Vol 177. pp. 419-425, (2008).

See also the US EPA web page, "The Inside Story: A Guide to Indoor Air Quality" at http://www.epa.gov/iaq/pubs/insidest.html and their warnings on ozone at http://www.epa.gov/iaq/pubs/ozonegen.html