Wildfire preparedness

Not meaningfully. Wildfire smoke is mostly PM2.5 — particles small enough to pass around and through loose-weave fabric and to reach deep into the lungs. Cloth and surgical masks are designed to catch droplets, not fine particles, and they do not seal to the face. For smoke you want a NIOSH-certified N95 or better, worn with a proper seal.

The number is the minimum percentage of fine particles the filter captures: 95%, 99% and 99.97%. The letter refers to oil resistance — "N" means not oil-resistant, which is fine for wildfire smoke. In practice the difference between them matters far less than fit: a well-sealed N95 outperforms a leaking P100, because air takes the path of least resistance around a bad seal.

Match the CADR (clean air delivery rate) to the room. A common industry rule of thumb is a smoke CADR of at least two-thirds of the room area in square feet — so a 300 sq ft room wants a smoke CADR around 200 or higher. Check that the unit uses a true-HEPA filter, and remember that a purifier only cleans the room it is in: size it for the room where you sleep first.

Yes, when built correctly. A box fan with MERV-13 furnace filters taped into a cube — often called a Corsi-Rosenthal box — has been shown in independent testing to remove fine particles effectively at a fraction of the cost of a commercial unit. It is louder and less elegant, but it is a legitimate option if purifiers are sold out or out of budget. Use a fan in good condition and never leave it running unattended overnight.

The essentials: several days of water and non-perishable food, prescription medications, a battery or hand-crank NOAA radio, flashlight and spare batteries, first-aid supplies, N95 masks, a phone charger or power bank, cash, and copies of key documents (ID, insurance, deeds). Add anything irreplaceable and whatever your pets need. Pack it before the season starts — the whole point is that you can leave in minutes without deciding what matters.

As soon as your local authorities tell you to — and earlier if you feel unsafe. You never need permission to leave. Evacuation orders can arrive with very little warning, and roads jam quickly once everyone moves at once, so leaving early is consistently safer than leaving late. If you have mobility needs, animals or children, plan for extra time. Current Wildfires is not an emergency service: always follow your local emergency agencies.

Wind-driven embers can travel well ahead of a fire and land on a house long before — or without — the flame front ever arriving. They ignite what they find: dry leaves in gutters, mulch against walls, patio furniture, or they blow in through attic and crawlspace vents. This is why ember-resistant vent screening, clearing debris from roofs and gutters, and keeping the first five feet around the house free of flammable material do more than almost anything else you can buy.