THINKING ABOUT AIR FILTRATION SYSTEMS DURING SMOKEY TIMES
Air filtration, better sealed home, gives people more control over the air quality in the house
MONTEREY >> With wildfires still raging in parts of the state bringing in smoke to Monterey County, local residents are thinking of ways to make the air in their homes cleaner on days when the air outside reaches unhealthy levels.
“The most important thing to think about is that it needs to be a balanced system with the supply of air coming in and the exhaust going out,” said Rob Nicely, Carmel Building and Design president.
A few weeks ago, air quality in the region had become so bad that an orange hue darkened the sky and people were warned to stay indoors due to the unhealthy conditions. Those conditions were coupled with high temperatures making for an uncomfortable situation in many homes where windows needed to be closed to keep out the bad air.
Nicely said that two of his clients have recently asked about incorporating an air filtration system into their home design specifically to combat smoke and bad air days. He had a few words of advice for them.
“When you have an air filtration system, it goes hand-inhand with the tighter envelope for the house,” said Nicely.
That tighter envelope is the seal between the inside and outside of a structure that gives people more control over the air quality in the house. The design helps to decrease or eliminate leakage in a house — those gaps
and holes around pipes, joint seams, doorways, and windows.
If the air filtration system is not balanced — meaning equal pressure coming in and going out — it can suck bad outside air through those leaky areas and reduce the effectiveness of the system.
“It does decrease the efficiency of the filtration system by about 50%,” said Nicely.
In very tightly enveloped homes that are supported by a mechanical ventilation system, such as in Passive House design, it is possible to fit a high-efficiency particulate air filter to the centralized system.
High-efficiency particulate air or HEPA filters are 99.97% efficient for removing particles less than 0.3 microns.
In September, there were a number of days where the air quality in the region registered between moderate to unhealthy, when PM2.5 levels were high due to smoke from many wildfires and prompting many to curtail outdoor activity.
To reduce exposure to fine particle pollution, which makes up much of wildfire smoke, national experts and those from the Monterey Bay Air Resources District advise people stay indoors in an area with filtered air because fine particulate matter — PM2.5, or particle matter of less than 2.5 microns — can make its way deep into the lungs and absorb into the bloodstream leading to a host of health problems or exacerbating existing conditions.
Air cleaners that remove particles include high-efficiency mechanical filters and electronic air cleaners.
Mechanical air cleaners draw air through a fibrous or metal filter with different sized pores that trap particles. These devices should, at a minimum, use medium efficiency filters, but high-efficiency particulate air filter- equipped mechanical models are recommended because they remove more of the smaller particles of concern and do not emit ozone.
Units that produce ozone can increase pollution in a home and be detrimental to a person’s health.
Since most homes are not designed within a tightly sealed envelope and purchasing filtration systems for the entire house may be too costly, people can consider creating a clean room within the house in a space with as few windows and doors as possible, such as a bedroom, Nicely said.
The space can rely on a mechanical air cleaner with a HEPA filter, but can also incorporate a throughthe-wall ventilation system to provide balance.
In the meantime, Nicely said that as much as there are ways to affect this, it really speaks to increasing the integrity of the boundary between the inside and the outside of a home by identifying and dealing with the gaps, holes, and seams where a house leaks.
One of the cheapest and most effective things to do is walk around your house and feel where a breeze or cool air is coming through and insulate or use caulking to seal it up, said Nicely.