The moment a wildfire starts near you, you'll get an instant alert and simple tips to reduce your smoke exposure.
30xSmaller than a human hair
Fine enough to reach deep into the lungs. A MERV 13 is built to capture it.
It Doesn't Stay Local
Smoke rides the wind far downwind — you can get smoky air with no fire nearby.
Simple steps to reduce indoor exposure.
During smoke events, the EPA recommends upgrading to a MERV 13 filter — or the highest-rated filter your system can handle — to help reduce the fine particles smoke brings indoors. MERV 13 is the level most home HVAC systems can run while still capturing PM2.5, the fine particulate that makes up the bulk of wildfire smoke.
Over 70,000 wildfires burn in the U.S. every year.
Wildfire smoke can travel 1,000+ miles, affecting states that aren't even near the blaze.
Exposure to wildfire smoke can worsen asthma, trigger heart issues, and lead to ER visits.
Indoor air can hold more fine particles during wildfire events unless it's properly filtered.
The EPA advises using MERV 13 filters or portable HEPA air cleaners during wildfire smoke events.
Use the live wildfire smoke tracker and upgrade your air filters today to protect your lungs and your home.
Shop Filters For Smoke Protection
Wildfire smoke in San Diego County can come from local brush fires, from fires elsewhere in Southern California, or from winds that push smoke over the mountains toward the coast. Conditions can look fine in the morning and worsen later when onshore flow or Santa Ana winds develop.
In this blog, we explain how to check live smoke today, what local patterns to watch, what to do indoors, and how to keep HVAC filters ready.
Check the AirNow Fire and Smoke Map in the morning and again if the wind changes or a Santa Ana starts.
If AQI is over 100, cut back time outside, especially for kids, older adults, and anyone with breathing or heart problems.
Keep the house closed up, run A/C or HVAC on recirculate, and use the highest MERV filter your system can handle.
Use a HEPA purifier in one room to have a cleaner space.
Go to the AirNow Fire and Smoke Map.
Enter “San Diego, CA” or your ZIP code.
Review the map for:
Zoom north toward Riverside/Orange counties and east toward the mountains. Smoke from an inland fire can move west later in the day if the wind turns onshore.
Coastal influence: Morning marine air can be clearer, then smoke or haze can appear later with onshore winds.
Santa Ana/offshore winds: When winds blow from the desert toward the coast, smoke from inland or north county fires can reach the metro area quickly.
Canyons and passes: Smoke can drain or funnel through lower terrain into populated areas even if the fire is not close.
Because of these shifts, one check in the morning is not always enough.
Keep outdoor air out
Close windows and doors. Set central A/C or HVAC to recirculate so the system is not bringing in smoky air. If there is a fresh-air intake you can close temporarily, do that during smoke.
Run the fan to filter
Set the thermostat fan to “On” instead of “Auto” during smoky hours. That keeps air moving through the filter.
Use a higher MERV if your system allows it
Many homes run MERV 8 or MERV 11 on normal days. During smoke, you can move to MERV 13 if the system still has normal airflow and comfort. Keep extra filters because smoke can load them faster.
Make one cleaner room
Pick a bedroom or main living area, close the door, and run a portable True HEPA purifier in that room. If you do not have a HEPA unit, you can use a newer box fan with a high-efficiency filter taped to the intake side and run it while you are in the room. Do not leave DIY units unattended.
Limit indoor sources
Avoid candles, incense, heavy frying, and long runs of bath/kitchen exhaust during smoky periods. These can add particles or pull smoky air inside.
Plan workouts, dog walks, and errands for the cleanest hours based on the map. When AQI is over 100, sensitive groups should stay indoors more. If you must be outside in heavy smoke, use a well-fitting N95 or P100 respirator. Cloth masks and loose surgical masks do not filter fine wildfire smoke the same way. In the car, keep windows closed and set the A/C to recirculate.
Do not wait for a 60–90 day change if San Diego just had several smoky days. Pull the HVAC filter and look at it. Replace early if:
the media looks dark or matted
the house smells smoky when the A/C starts
airflow at the vents feels weaker than normal
Check and replace room purifier filters or DIY box-fan filters the same way.
Filterbuy provides pleated HVAC and A/C filters in MERV 13, which is highly recommended for wildfires. Filters are made in the USA, available in standard and custom sizes for a tight fit, and ship fast with free U.S. delivery. Auto Delivery makes sure you have a clean filter on hand before the next San Diego smoke or Santa Ana event.
Use the AirNow Fire and Smoke Map. Search “San Diego, CA” or your ZIP and check the AQI, PM2.5, and smoke plume layers.
Check in the morning, then check again if the wind changes, if you hear about a new fire, or if you see haze moving in.
Winds can bring smoke in from inland San Diego County, Riverside, or even farther north. Santa Ana winds especially can push smoke toward the coast.
At AQI above 100, sensitive groups (kids, older adults, asthma, heart/lung issues) should slow down outdoor activity.
Close windows and doors, run A/C or HVAC on recirculate, and make sure a good filter is in place.
Use the highest MERV your system can handle while keeping normal airflow. Many homes use MERV 8 or 11 daily and go to MERV 13 during smoke if the system allows it.
It helps to have one room that is cleaner. Run a True HEPA purifier in a bedroom or main room and keep the door closed.
Wildfire smoke can load a filter more quickly than normal dust. Check it early and replace if it looks dark or matted.
Keep use short during smoky hours. Those fans can pull smoky outdoor air into the house.
No. Always follow local fire, evacuation, and air-quality alerts for San Diego County.
