California air quality

El Granada, California Air Quality

San Mateo County37.503, -122.469

The nearest monitor to El Granada, at Redwood City, 15 miles away, measured an index of 24 at Sun, 11:00 AM PDT, which is Good for fine particles (PM2.5). Bay Area Air District forecasts Good for Redwood City today and Good tomorrow.

Measured now
24 · Good
Today
41 · Good
Tomorrow
43 · Good
Pollutant
PM2.5

Fine particles on the map

Forecast fine particulate matter from NOAA’s National Air Quality Forecast Capability over El Granada, California. Open it for the live map, where it pans and zooms.

Forecast fine particulate matter from NOAA’s National Air Quality Forecast Capability over El Granada, California Open the live map with the particulate forecast

Map layer from NOAA National Air Quality Forecast Capability. Boundaries from the Iowa Environmental Mesonet.

Alerts in force

An Air Quality Alert is issued by the National Weather Service on behalf of a state or local agency when pollution is expected to reach a level that harms health. An Air Stagnation Advisory means the air will not move enough to clear what is already in it.

None are in force near El Granada right now. All California warnings.

Now

Good

Nearest monitor
Redwood City, 15 miles away (site 060811001)
Index measured
24 · Good
Measured at
Sun, 11:00 AM PDT
Fine particles
4 µg/m³
Ozone
24 ppb
Reporting area
Redwood City, CA, 14 miles away
Reported by
Bay Area Air District
Area index
24 · Good

Measured, not modeled. AirNow observations are preliminary until the operating agency certifies them, which happens months later.

Today and tomorrow

Bay Area Air District's own forecast for Redwood City, written by a forecaster rather than read off a model.

DayCategoryIndexPollutant
TodayGood41Ozone
TomorrowGood43Ozone
Tuesday, September 22GoodOzone
Wednesday, September 23GoodOzone

Hour by hour

NOAA’s National Air Quality Forecast Capability, bias-corrected against monitors, for this town’s own coordinate. The worst hour ahead is an index of 38, Good, around Sun, 11:00 AM PDT, from the run issued Sun, 5:00 AM PDT. This is a model, not a measurement.

HourIndexCategoryPM2.5Ozone
Sun, 7:00 AM PDT25Good4.1
Sun, 8:00 AM PDT24Good4.3
Sun, 9:00 AM PDT27Good5.7
Sun, 10:00 AM PDT33Good7.1
Sun, 11:00 AM PDT38Good7.8
Sun, 12:00 PM PDT38Good7.1
Sun, 1:00 PM PDT38Good6.727.1
Sun, 2:00 PM PDT36Good6.227.3
Sun, 3:00 PM PDT37Good6.927.6
Sun, 4:00 PM PDT37Good6.727.8
Sun, 5:00 PM PDT35Good628.1
Sun, 6:00 PM PDT34Good628.5
Sun, 7:00 PM PDT32Good5.328.9
Sun, 8:00 PM PDT32Good5.329.1
Sun, 9:00 PM PDT29Good4.729.4
Sun, 10:00 PM PDT27Good4.529.9
Sun, 11:00 PM PDT28Good3.730.3
Mon, 12:00 AM PDT28Good430.7
Mon, 1:00 AM PDT28Good4.131
Mon, 2:00 AM PDT28Good3.930.8
Mon, 3:00 AM PDT28Good430.5
Mon, 4:00 AM PDT28Good3.830.7
Mon, 5:00 AM PDT28Good4.130.7
Mon, 6:00 AM PDT28Good4.830.3
Mon, 7:00 AM PDT28Good4.530.2
Mon, 8:00 AM PDT27Good4.530
Mon, 9:00 AM PDT27Good5.329.7
Mon, 10:00 AM PDT32Good6.829.7
Mon, 11:00 AM PDT33Good6.329.9
Mon, 12:00 PM PDT33Good5.829.8
Mon, 1:00 PM PDT32Good5.529.6
Mon, 2:00 PM PDT31Good5.529.5
Mon, 3:00 PM PDT34Good6.829.1
Mon, 4:00 PM PDT34Good6.428.9
Mon, 5:00 PM PDT34Good628.9
Mon, 6:00 PM PDT34Good6.328.9
Mon, 7:00 PM PDT33Good5.629
Mon, 8:00 PM PDT32Good5.328.9
Mon, 9:00 PM PDT29Good4.529.1
Mon, 10:00 PM PDT27Good4.329.4
Mon, 11:00 PM PDT27Good3.929.8
Tue, 12:00 AM PDT28Good4.430
Tue, 1:00 AM PDT28Good3.530.1
Tue, 2:00 AM PDT27Good3.629.7
Tue, 3:00 AM PDT27Good4.529
Tue, 4:00 AM PDT26Good428.6
Tue, 5:00 AM PDT25Good3.927.8
Tue, 6:00 AM PDT25Good2.927.1
Tue, 7:00 AM PDT24Good4.326.4
Tue, 8:00 AM PDT23Good3.525.6
Tue, 9:00 AM PDT22Good3.924.8
Tue, 10:00 AM PDT23Good524.5
Tue, 11:00 AM PDT28Good5.724.7
Tue, 12:00 PM PDT26Good4.525
Tue, 1:00 PM PDT26Good4.625.4
Tue, 2:00 PM PDT23Good3.825.9
Tue, 3:00 PM PDT26Good5.126.3
Tue, 4:00 PM PDT27Good5.126.9
Tue, 5:00 PM PDT28Good5.427.9
Tue, 6:00 PM PDT29Good5.528.7
Tue, 7:00 PM PDT28Good4.729.4
Tue, 8:00 PM PDT27Good4.329.3
Tue, 9:00 PM PDT27Good4.929.7
Tue, 10:00 PM PDT29Good6.230.1
Tue, 11:00 PM PDT31Good6.130.3
Wed, 12:00 AM PDT31Good5.530.3
Wed, 1:00 AM PDT29Good4.930.2
Wed, 2:00 AM PDT28Good4.329.7
Wed, 3:00 AM PDT27Good4.728.9
Wed, 4:00 AM PDT27Good4.728.4
Wed, 5:00 AM PDT25Good2.927.5

Fine particles in micrograms per cubic meter, ozone in parts per billion as an 8-hour average. The index for each hour is EPA’s: the ozone figure is already the 8-hour average the ozone index is defined on, and the particle figure is run through EPA’s NowCast, which is how an hourly PM2.5 concentration becomes an index.

Smoke

NOAA’s analysts have not drawn smoke over El Granada in satellite imagery today.

NOAA’s model forecasts near-surface smoke peaking at 0.2 µg/m³ around Mon, 1:00 PM PDT.

Smoke on the radar over El Granada

What this means

Good

Air quality is satisfactory, and air pollution poses little or no risk.

Who is affected
Nobody is expected to be affected.
What to do
It is a good day to be outside.
Index range
0 to 50

Category descriptions are the Environmental Protection Agency’s own.

What these numbers are. An index beside a monitor’s name is a measurement, published hourly by AirNow and preliminary until the operating agency certifies it. A category for today or tomorrow is a state or local agency forecaster’s own forecast for a reporting area. An hourly index is NOAA’s air quality model on a five-kilometer grid, not a reading from any instrument. Where a town has no monitor within reach, only the model figures appear, and the page says so.

Nearby

The nearest towns with a page of their own, closest first.

Weather forecast for El GranadaWarnings in San Mateo CountyLive radar over El GranadaCalifornia air quality

Sources

Observations and daily forecasts from AirNow, the US Environmental Protection Agency’s program with NOAA, the National Park Service, NASA, tribal, state and local agencies. Hourly forecasts from NOAA’s National Air Quality Forecast Capability. Smoke analysis from NOAA’s Hazard Mapping System. Alerts from the National Weather Service. Index categories and breakpoints are EPA’s, as revised in 2024.