Hearst Castle, Cambria Air Quality Forecast - Today, Tomorrow
Air Quality Today
Today (10 October): Air quality in Hearst Castle is moderate. AQI, PM2.5, and O3 are moderate; NO2 is fair; PM10, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 5:00 AM (O3: 47.3/100).
Air Quality Tomorrow
Tomorrow (11 October 2026): Air quality in Hearst Castle is poor. AQI worsens to poor; PM10 increases to fair; NO2 increases to moderate; O3 increases to poor; PM1 increases to fair; all other pollutants stay as today. Pollution peaks around 7:00 AM (O3: 60.5/100).
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Air Quality
Today - 10 October
| Pollutant | Level | Value |
|---|---|---|
| AQI | Moderate | 47.3/100 |
| PM2.5 (fine particles) | Moderate | 41.2/100 |
| PM10 (coarse particles) | Good | 18.4/100 |
| NO2 (nitrogen dioxide) | Fair | 37.7/100 |
| O3 (ozone) | Moderate | 47.3/100 |
| SO2 (sulfur dioxide) | Good | 2.4/100 |
| CO (carbon monoxide) | Good | 0.6/100 |
| HCHO (formaldehyde) | Good | 2.6/100 |
| PM1 (ultrafine particles) | Good | 13.9/100 |
Tomorrow - 11 October
| Pollutant | Level | Value |
|---|---|---|
| AQI | Poor | 60.5/100 |
| PM2.5 (fine particles) | Moderate | 46.4/100 |
| PM10 (coarse particles) | Fair | 25.5/100 |
| NO2 (nitrogen dioxide) | Moderate | 56.8/100 |
| O3 (ozone) | Poor | 60.5/100 |
| SO2 (sulfur dioxide) | Good | 4.3/100 |
| CO (carbon monoxide) | Good | 0.7/100 |
| HCHO (formaldehyde) | Good | 4.4/100 |
| PM1 (ultrafine particles) | Fair | 23.8/100 |
Local Environmental Conditions
With little dense development around this site in Cambria, local traffic emissions are modest. The open grass and scrubland around the area can add dust in dry weather and smoke from occasional fires. Trees nearby help filter some particles from the air, though in hot weather they also emit compounds that feed ozone formation. On some days, pollution drifting in from farther away outweighs local sources.
With summer temperatures averaging only about 18°C, ozone rarely becomes a serious problem. In contrast, cooler, still evenings from January to March, averaging about 12°C, tend to hold exhaust close to busy streets. In addition, with little rain from April to October, dust from dry fields and open ground becomes more common. Wildfire smoke is most likely from June to October, sometimes turning the sky hazy for days.
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Frequently Asked Questions About Air Quality in California
Is air quality bad in Hearst Castle right now?
On 10 October 2026, overall air quality in Hearst Castle is moderate. AQI is the main air quality indicator at 47.3/100. Pollution peaks around 5:00 AM (O3: 47.3/100).
Will air quality be worse tomorrow in Hearst Castle?
On 11 October 2026, air quality conditions in Hearst Castle will be worse than today, with AQI forecast at poor at 60.5/100. Pollution peaks around 7:00 AM (O3: 60.5/100).
When is air pollution at its worst in Hearst Castle?
With summer temperatures averaging only about 18°C, ozone rarely becomes a serious problem. In contrast, cooler, still evenings from January to March, averaging about 12°C, tend to hold exhaust close to busy streets. In addition, with little rain from April to October, dust from dry fields and open ground becomes more common. Wildfire smoke is most likely from June to October, sometimes turning the sky hazy for days.
Are air quality levels in Hearst Castle 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. |