Air quality problems are reaching local newspapers in the form of warnings on a more frequent basis. Published studies by academic researchers detail problems with fine particle pollution in the areas of schools, medical facilities and downtown neighborhoods. As more studies develop it is clear that air quality problems are not only an urban problem but they crossover into suburban and even rural communities. A particularly susceptible segment of our population includes those with elevated cardiovascular risks.
One paper, by Professor Robert F. Storey, notes that “More than three million deaths worldwide are caused by air pollution each year.” He also notes “Avoiding air pollution where possible may help to reduce cardiovascular risk and cardiologists should incorporate this information into lifestyle advice for their patients.”
Although the only control we have over pollution in the outdoor air is regulation we can always take steps to prevent pollution from affecting us indoors by using air filtration to remove harmful contaminants. In most commercial buildings, design engineers primarily incorporate air filters with a MERV of 13, a value of performance for an air filter when tested per a Standard as published by the American Society of Heating, Refrigeration and Air-Conditioning Engineers. It is also a good idea to consider a filter’s MERV-A number, it should match the standard MERV number indicating that it will also maintain its efficiency over time.
A MERV 13 air filter is the fulcrum of the MERVs range of 1 through 16 wherein that value and the corresponding filter efficiency provides a removal efficiency on sub-micron size particles. Filters below MERV 13 have a negligible efficiency on sub-micron size particles and those above MERV 13 have a higher resistance to airflow taxing the system fan and requiring more energy to move air through the filter. For efficiency and energy use MERV 13 usually provides the best value for a filtration dollar. Higher efficiencies are usually specific to applications, as are MERV 14 filters for medical facility use.
Although MERV 13 filters can be applied in schools, offices, and retail spaces because of the industrial HVAC systems used, the systems in residences simply do not have the fan power to move air through the higher efficiency air filters. The highest MERV that may be applied here is often limited to a maximum of a MERV 8 air filter, excellent for the removal of pollen and other common allergens.
In periods of high pollution the best thing a homeowner can do, according to Professor Storey, is limit physical activity.