Individual Preparedness for Distant Wildfires and the Delta Variant in the United States: A Survey of 2,250 US Residents

Srikrishna, D.

Background COVID-19 virus travels in the air and collects indoors through tiny particles from exhaled breath, and remains a growing concern globally especially since case studies of vaccine breakthrough infections are being reported. Last year's wildfires resulted in the worst air quality on record in the Western US due to toxic wildfire smoke (PM 2.5 pollution) traveling from distant wildfires and this year can potentially be even worse due to extremely dry conditions. Precautions such as high-filtration (Hi-Fi) masks and HEPA air purifiers are useful to effectively reduce inhalation of most of these toxic aerosols. Whereas the lack of fit or filtration in a mask or use of an air purifier of insufficient size (capacity) for the room can inadvertently render these precautions ineffective. Here we investigate the public's concerns about wildfires and the COVID-19 variants (e.g. delta), their use of aerosol precautions, and whether these are being done in an effective manner. Methods We conducted possibly the largest, national survey (2,250 US residents) to date in order to understand the public concerns about airborne threats and their usage of airborne (aerosol) precautions. Results We find over 66% of US residents surveyed are worried about inhaling COVID-19 and its variants, and 52% are worried about toxic wildfire particles in the air. In the mountain and pacific regions the latter rises to 73%. Only a quarter are using masks with higher filtration and high level of fit (or Hi-Fi masks e.g. N95 or similar such as elastomeric N95 or KF94). Two-thirds are still using loose-fitting cloth or surgical masks. Just over 40% of respondents report using air purifiers at home, and of this group only 40% use it in their bedroom where they sleep. Of those using air purifiers, the majority said they chose the size of their air purifier based on "most popular" models, "recommendations," or "reviews." However, of those using air purifiers only 42% reported doing a calculation (or using a calculator) to estimate the right size of air purifier needed for the room they are using it in. Notably, a much higher percentage of people (than average) reported use of Hi-Fi masks and home air purifiers in certain occupations such as doctors, healthcare, first responders, public safety, engineering, military, and construction. Conclusion National survey data suggests most Americans are worried about wildfire smoke and Covid variants (e.g. delta variant) but a majority are not prepared for it. This data reveals five specific things that can be immediately done by a majority of Americans with off-the-shelf products to prepare for these and other aerosolized risks (1) use HEPA air cleaners in rooms wherever significant time is spent such as bedrooms, living rooms, classrooms, offices, etc. (2) correctly estimate the size of the HEPA air cleaner for each room using a purpose-built calculator if needed (3) override the auto setting to maximum speed in shared spaces such as classrooms and offices since the fan-speed sensors in HEPA air cleaners typically detect wildfire smoke but not accumulation of virus from exhaled breath (4) use Hi-Fi masks instead of the more common cloth masks and loose-fitting surgical masks e.g. N95, elastomerics, KF94, surgical masks with fitters, etc. (5) "stock up" on HEPA air cleaners and Hi-Fi masks as needed in advance of the Western US wildfire season when there are expected to be shortages once the air quality rapidly deteriorates. Widespread access and adoption of these same aerosol precautions will be useful for future pandemics and national biodefense.