Tunnel Tree, Yosemite Valley Air Quality Forecast - Today, Tomorrow
Air Quality Today
Today (6 October): Air quality in Tunnel Tree is moderate. AQI, PM2.5, and PM10 are moderate; O3 is fair; NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 10:00 AM (PM10: 43.3/100).
Air Quality Tomorrow
Tomorrow (7 October 2026): Air quality in Tunnel Tree is moderate. O3 increases to moderate; all other pollutants stay as today. Pollution peaks around 9:00 AM (PM2.5: 48.3/100).
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Air Quality
Today - 6 October
| Pollen species | Level | Value |
|---|---|---|
| AQI | Moderate | 43.3/100 |
| PM2.5 (fine particles) | Moderate | 43.0/100 |
| PM10 (coarse particles) | Moderate | 43.3/100 |
| NO2 (nitrogen dioxide) | Good | 6.9/100 |
| O3 (ozone) | Fair | 37.1/100 |
| SO2 (sulfur dioxide) | Good | 1.8/100 |
| CO (carbon monoxide) | Good | 0.4/100 |
| HCHO (formaldehyde) | Good | 1.8/100 |
| PM1 (ultrafine particles) | Good | 9.4/100 |
Tomorrow - 7 October
| Pollen species | Level | Value |
|---|---|---|
| AQI | Moderate | 48.3/100 |
| PM2.5 (fine particles) | Moderate | 48.3/100 |
| PM10 (coarse particles) | Moderate | 43.8/100 |
| NO2 (nitrogen dioxide) | Good | 13.0/100 |
| O3 (ozone) | Moderate | 45.0/100 |
| SO2 (sulfur dioxide) | Good | 1.7/100 |
| CO (carbon monoxide) | Good | 0.4/100 |
| HCHO (formaldehyde) | Good | 2.8/100 |
| PM1 (ultrafine particles) | Good | 13.5/100 |
Local Environmental Conditions
This location in Yosemite Valley lies in a lightly developed area, where local traffic adds relatively little to air pollution. Trees nearby help filter some particles from the air, though in hot weather they also emit compounds that feed ozone formation. Light average winds mean local emissions are not always carried away quickly. Air arriving from elsewhere in the region adds to what is produced locally.
Cold spells from November to March, at around 2°C on average, are when smoke from wood burning and traffic lingers longest. From July to August, strong sunshine and temperatures around 24°C drive ozone formation, with levels peaking in the afternoon. Wildfire season runs roughly from June to September, when smoke from fires, near or far, can bring hazy days and very poor air quality.
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Frequently Asked Questions About Air Quality in California
Is air quality bad in Tunnel Tree right now?
On 6 October 2026, overall air quality in Tunnel Tree is moderate. AQI is the main air quality indicator at 43.3/100. Pollution peaks around 10:00 AM (PM10: 43.3/100).
Will air quality be worse tomorrow in Tunnel Tree?
On 7 October 2026, air quality conditions in Tunnel Tree will be similar to today, with AQI forecast at moderate at 48.3/100. Pollution peaks around 9:00 AM (PM2.5: 48.3/100).
When is air pollution at its worst in Tunnel Tree?
Cold spells from November to March, at around 2°C on average, are when smoke from wood burning and traffic lingers longest. From July to August, strong sunshine and temperatures around 24°C drive ozone formation, with levels peaking in the afternoon. Wildfire season runs roughly from June to September, when smoke from fires, near or far, can bring hazy days and very poor air quality.
Are air quality levels in Tunnel Tree based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
Understanding the Scale
The 0–100 air quality scores represent risk levels, not direct air pollutant concentrations. Higher scores indicate higher risk.
Air Quality
| Good | 0-20 | Low air quality risk. Air quality is expected to be good, with low levels of pollution. |
| Fair | 20-40 | Generally low air quality risk. Air quality is expected to be acceptable, with some pollution present. |
| Moderate | 40-60 | Moderate air quality risk. Air pollution is elevated and air quality may be less favorable. |
| Poor | 60-80 | High air quality risk. Air pollution is high and air quality is expected to be poor. |
| Very Poor | 80-100 | Very high air quality risk. Air pollution is very high and air quality is expected to be very poor. |