The Santa Rosa monitor read 211 on Friday, in the “very unhealthy” range and by a wide margin the worst air anywhere within 100 miles. The forecast has Saturday still unhealthy and the air clearing by Tuesday. Fifteen miles east, in Napa, it is far cleaner.
Smoke from the Woodside Fire on the Sonoma coast has settled over the Santa Rosa plain and the valley behind it. The Bay Area Air District’s monitor at Santa Rosa recorded fine-particulate air quality of AQI 211 on Friday. It is nine miles from Kenwood and the nearest official station to these three towns. That is in the “very unhealthy” band, one step above the level at which healthy adults are told to limit prolonged exertion outdoors. It read 165 on Thursday. Sonoma County’s health officer has an air quality advisory in force.
How long it lasts
The official forecast runs: Saturday AQI 152, still “unhealthy”; Sunday and Monday moderate; Tuesday good. The weekend is the part to plan around. The worst should be behind us by the start of next week if the fire does not spread again. At 30% containment on Friday morning, that is a reasonable assumption but not a safe one.
Smoke does not spread evenly. The fire is more than 50 miles away on the coast, and its plume drifted inland and then sank into the low ground. The Santa Rosa plain and the Sonoma Valley form a basin, and overnight inversions put a lid on it. That is why the worst readings come in the small hours and early morning. The same smoke is now reaching Sacramento, where the air district has called a Spare the Air day.
Where the clean air is
Every official reading within 130 miles of Kenwood on Friday is ranked below. Santa Rosa is the worst by far, at nearly four times the next worst.
| Where | Miles | AQI | Category |
|---|---|---|---|
| Santa Rosa (us) | 9 | 211 | Very unhealthy |
| Napa | 15 | 55 | Moderate |
| San Rafael | 31 | 57 | Moderate |
| Concord | 41 | 52 | Moderate |
| San Francisco | 46 | 53 | Moderate |
| Ukiah | 62 | 48 | Good |
| Auburn | 86 | 24 | Good |
| San Lorenzo Valley | 95 | 27 | Good |
You do not have to go far. Napa, 15 miles away over the Mayacamas, was reading 55 against our 211. South into Marin or across to Contra Costa was much the same. For clean air, Ukiah up 101 was the nearest “good” reading, and the Sierra foothills and the Santa Cruz mountains were cleaner still.
Before you drive, check AirNow’s fire and smoke map. These are reporting-area readings, not your street, and smoke moves, so trust the map over a table from this morning. A car is a fairly good air cleaner in its own right if you set the ventilation to recirculate, so the drive itself is not the problem.
If you are staying put
The county advises keeping windows and doors closed, air conditioning and car ventilation on recirculate, the fresh-air intake shut and filters clean. Stay hydrated. Don’t mow, run a leaf blower, barbecue or light a wood fire. Older adults, pregnant women, children and anyone with heart or lung trouble feel this first and worst.
A cloth or surgical mask does almost nothing against particles this fine. A properly fitted N95 or P100 does much better.
The cheapest effective thing you can do indoors is to tape a MERV-13 furnace filter to the back of a box fan, arrow pointing into the fan. It costs about $30 and noticeably clears a room. Run it while you are awake rather than overnight unattended.
A correction, and what we changed
Earlier on Friday this paper published an air quality figure of around AQI 50 for the valley and said healthy people would notice nothing. That was wrong. The figure came from a gridded forecast model that, as we found while checking a follow-up, was not resolving the smoke plume at all. It returned nearly identical readings for the entire county, including at the fire itself, while the nearest real monitor was reading 211.
The earlier report has been corrected. The live air quality figure on our front page and on the fire, weather and water dashboard now comes from the Bay Area Air District’s monitors, not from a model. It refreshes every half hour and names the station it came from. The model survives only as a fallback if the monitor feed goes down, and it is labeled as modeled when it appears. A number that understates the danger when the danger is real is worse than no number at all.
There is still no ground-level air monitor in Kenwood, Glen Ellen or Oakmont. Santa Rosa, nine miles away and slightly lower, is the closest true reading available. If you can smell smoke, believe your nose over any number, including ours.
Sources: AirNow reporting-area file (Bay Area Air District observations and forecasts), retrieved July 31, 2026; Sonoma County Department of Health Services air quality advisory; CAL FIRE incident data. Distances are straight-line from Kenwood.