Quick answer: buy a HEPA purifier whose smoke CADR fits the room you’ll shelter in, confirm it’s on CARB’s certified list, and keep spare filters on hand before fire season. Run it on high with windows and doors closed when smoke arrives.
California has its own rule here. Since 2010, every portable indoor air cleaner sold in the state has had to be certified by the California Air Resources Board, which caps ozone emissions at 0.050 parts per million [1]. CARB’s smoke advice is to set up a clean air space: one room big enough for everyone, with a certified portable air cleaner on its highest setting and the windows and doors shut [2]. CARB also notes that wildfire smoke can travel hundreds of miles, so a fire far away can still mean bad air at home [2].
At a glance
- CARB certification required since
- 2010, for all portable indoor air cleaners [1]
- Ozone limit
- 0.050 ppm (50 ppb) [1]
- Smoke particle size
- 2.5 micrometers and smaller [2]
- CADR for a 600 sq ft room
- About 390 cfm, 8-ft ceilings [3]
- HVAC filter during smoke
- MERV 13 or higher, fan set to on [2]
How we chose
- On CARB’s certified list, checked by model number on November 2, 2026 [1].
- Tested smoke CADR from the ENERGY STAR certified list, which also gives each unit’s measured ozone output and yearly energy use [4]. We don’t use box claims.
- Fan-and-filter design. All five use a filter as their main cleaning method, which the EPA says is how portable cleaners reach high CADR [3].
- Recall check: no CPSC recalls found for these brands’ air purifiers (checked 2026-11-02) [5].
Our picks
Best for: Bedrooms up to about 350 square feet
Levoit Core 400S
Tested smoke CADR above 230 at zero measured ozone, in a compact unit that fits the clean-room setup CARB describes.
- Smoke CADR 231; PM2.5 CADR 236 [4]
- Room size 358 sq ft (ENERGY STAR) [4]
- Measured ozone 0.00 ppb [4]
- About 237 kWh a year [4]
Safety check: CARB certified (G-21-166). No CPSC recall found (checked 2026-11-02).
Watch out: Too small for an open living area; size up for rooms over about 350 square feet.
See it on Amazon → We chose it from specs and safety records; we haven't tested it ourselves.
Best for: Lowest running cost in its size
Honeywell HPA4300B Allergen Plus HEPA
Nearly the same tested smoke CADR as the Levoit, with the lowest yearly energy use of the mid-size picks.
- Smoke CADR 229; PM2.5 CADR 233 [4]
- Room size 355 sq ft (ENERGY STAR) [4]
- Measured ozone 0.00 ppb [4]
- About 185 kWh a year [4]
Safety check: CARB certified (G-26-133). No CPSC recall found (checked 2026-11-02).
Watch out: ENERGY STAR lists it on the market since July 2026, so there's little long-term track record yet.
See it on Amazon → We chose it from specs and safety records; we haven't tested it ourselves.
Best for: Mid-size living rooms
Winix AT40
Tested smoke CADR above 260 for rooms around 400 square feet.
- Smoke CADR 265; PM2.5 CADR 261 [4]
- Room size 411 sq ft (ENERGY STAR) [4]
- Measured ozone 0.00 ppb [4]
- About 272 kWh a year [4]
Safety check: CARB certified (G-26-150). CARB lists it as an electronic air cleaner, which means it passed CARB's ozone test. No CPSC recall found for Winix air purifiers (checked 2026-11-02).
Watch out: Because CARB classes it as electronic, check the manual for any ionizer setting and how to switch it off if you prefer filter-only cleaning.
See it on Amazon → We chose it from specs and safety records; we haven't tested it ourselves.
Best for: Open floor plans up to about 580 square feet
Coway Airmega 400 (AP-2015F)
Smoke CADR near 380, enough for the EPA's 600-square-foot example on its own, with zero measured ozone.
- Smoke CADR 376; PM2.5 CADR 380 [4]
- Room size 583 sq ft (ENERGY STAR) [4]
- Measured ozone 0.00 ppb [4]
- About 366 kWh a year [4]
Safety check: CARB certified (G-26-006). No CPSC recall found (checked 2026-11-02).
Watch out: Uses the most electricity of the picks, about 366 kWh a year at ENERGY STAR's test conditions.
See it on Amazon → We chose it from specs and safety records; we haven't tested it ourselves.
Best for: Large rooms and the most smoke-heavy days
Blueair Blue Pure 211i Max (3613111100)
Highest tested smoke CADR on this page, sized by ENERGY STAR for nearly 700 square feet, with modest energy use for its size.
- Smoke CADR 443; PM2.5 CADR 450 [4]
- Room size 687 sq ft (ENERGY STAR) [4]
- Measured ozone 2.00 ppb, far under CARB's 50 ppb limit [1][4]
- About 259 kWh a year [4]
Safety check: CARB certified (G-23-076, listed as electronic). No CPSC recall found for Blueair (checked 2026-11-02).
Watch out: The biggest unit here. Its measured ozone is low but not zero, unlike the other picks.
See it on Amazon → We chose it from specs and safety records; we haven't tested it ourselves.
Buying guide
- Pick the room first, then match smoke CADR to its size using the EPA’s estimates [3]. For open plans, count the whole connected space.
- Check CARB’s list for the exact model number before you buy [1].
- Stock a spare filter before fire season, so you aren’t shopping for one during a smoke event.
- Upgrade your HVAC filter to MERV 13 or the highest your system can handle, and set the fan to “on” instead of “auto” during smoke [2].
- No purifier? CARB describes a box-fan filter (a 2012-or-newer UL or ETL fan with MERV 13 filters) as a stopgap [2].
Sources
Common questions
What does CARB-certified mean for an air purifier?
Since 2010, every portable indoor air cleaner sold in California must be certified by the California Air Resources Board. Certification covers electrical safety and limits ozone to 0.050 parts per million. It doesn't measure how well the unit cleans the air; CADR does that.
What CADR do I need for wildfire smoke?
The EPA estimates about 65 cubic feet per minute of CADR for a 100-square-foot room, rising to about 390 for 600 square feet, with 8-foot ceilings. Use the smoke CADR, and go higher for tall ceilings or open floor plans.
Should I buy an ionizer or ozone generator for smoke?
No ozone generators. The EPA says to avoid air cleaners that intentionally produce ozone, and says no federal agency has approved them for occupied spaces. Every purifier on this page is on CARB's certified list.