Wildfire smoke drifting from western Ontario and Minnesota is leading to air quality alerts across several U.S. states, prompting concern and advice on mitigating exposure. Air quality alerts have been issued for Michigan, Minnesota, Wisconsin, and Colorado, with smoke plumes also impacting visibility and air quality in New York, Massachusetts, and Illinois.
Experts predict that smoke levels could reach extremely hazardous conditions in affected areas, reminiscent of the severe air quality events experienced in June 2023. The National Weather Service (NWS) notes that wildfire smoke can elevate fine particulate matter (PM2.5) levels, which can exacerbate existing respiratory and heart conditions and lead to new breathing difficulties. Vulnerable populations, including children, older adults, and individuals with pre-existing respiratory illnesses, are particularly at risk.
In response to deteriorating air quality, information has emerged on creating do-it-yourself (DIY) air purifiers. One widely shared method is the Corsi-Rosenthal Box, a design developed by environmental engineer Dr. Richard Corsi and Jim Rosenthal, CEO of Tex-Air Filters. This open-source design utilizes four high-efficiency air filters and a standard box fan to capture airborne particles.
The assembly of a Corsi-Rosenthal Box is described as a process that can be completed in under an hour and costs approximately $80 to $100. The design combines four MERV 13-rated air filters arranged in a square, sealed together with duct tape. A 20-inch box fan is then secured to the top of the filter array, oriented to direct air upwards. A cardboard shroud is added to the fan to improve efficiency. According to 3M, this type of air purifier can be effective in improving air quality in large rooms with poor ventilation and has been shown to reduce PM2.5 by an average of 92%.
Maintenance for the DIY purifier involves replacing the filters every six months or when they appear visibly dirty. Additionally, some individuals may be eligible to use pre-tax flexible spending account (FSA) funds to purchase air purification devices, provided they have qualifying health conditions such as asthma or allergies and possess the necessary supporting documentation.
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