Unhealthy air quality resulting from wildfires poses significant risks to those who may be caught within it, but residents can take steps to ensure their homes are safe from intrusive smoke and particulates.
According to the Center For Disease Control, wildfire smoke--which is the product of gases and particles from burning trees and plant materials--can irritate one’s respiratory system and worsen chronic heart or lung disease. Children and the elderly are particularly vulnerable to the harmful effects of smoke inhalation.
Residents are often told to stay indoors during smoke advisories in order to protect their health. However, certain factors may compromise a structure’s insulation from unhealthy air.
In a Q&A published by the Lawrence Berkeley National Laboratory, Brett Singer and Rengie Chan, researchers with the lab's Indoor Environment Group, said that among multiple factors that can affect indoor air quality, a building’s ventilation is the most significant.
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"During smoke events, most people now know that they should keep windows closed, and that helps. But outdoor air may be coming in through mechanical systems--which occurs in most commercial buildings and some homes--and through uncontrolled air movement through cracks and openings in the building shell," Singer said.
Singer added unhealthy outdoor air can be prevented from entering a structure through filtration, mechanical systems or recirculating air that is already inside a building. He said equipping a home’s heating, ventilation and air conditioning (HVAC) system with high-efficiency air filters can dramatically decrease particulates in indoor air.
"An older home or commercial building that has not been upgraded and doesn’t have high performance filters can have indoor particle levels that are 70% to 80% of outdoor levels even when all the windows are closed," Singer said. "Homes built in the last 10 to 20 years and older homes that have had very good air sealing upgrades can have indoor particle levels that are only 50% or less of those outdoors, when windows are closed."
Chan said it is best to be prepared before the outbreak of a wildfire, as air filters can be difficult to come by during an active fire or smoke advisory.
"Have these higher efficiency air filters on hand and confirm ahead of time that the HVAC system can handle that kind of air filter," Chan said. "Whenever there are extreme events it’s pretty hard to buy filters, but filters make a significant difference."