Washington Blvd Air Quality Monitor

Current Air Quality at Your Home

2.2

PM2.5 µg/m³

AQI conversion (latest reading)

Current rank (of 13)

469.0

Particles ≥ 0.3 µm

1.9

PM1.0 µg/m³

4.1

PM10 µg/m³

VOC

Sensor humidity (%)

* Uncorrected PM2.5/AQI shown where correction data is unavailable. Rankings use the displayed PM2.5 values, including any starred uncorrected readings.

Air Quality Summary · Last 24 Hours

Average PM2.5: 5.0 µg/m³ — estimated PM2.5 AQI 27 (Good), using EPA's 2024 breakpoints.
Ranked #11 out of 12 tracked locations by average PM2.5 over the past 24 hours (lower is better; ties share a rank).
Lower average PM2.5 than 1 out of 11 comparison locations (9%).

Based on 120 corrected readings out of 120 available home readings in the last 24 hours. Each location uses its corrected average when available; otherwise its uncorrected average is used. Coverage may differ by location.

* Uncorrected value because correction data is unavailable. Rankings use the displayed PM2.5 values, including any starred uncorrected readings. This is a sensor-based estimate, not an official AQI.

PM2.5 measures some traffic-related fine particles.

Latest Readings by Location

Rank	Location	Count ≥ 0.3 µm	PM1.0	PM2.5	PM10	VOC	PM2.5 AQI conversion
1	Fremont - Ohlone Starbucks	687.0	2.6	0.0	6.2	-	0
2	San Mateo - Hills	337.0	0.7	0.8	3.6	-	4
3	Camelia - Fremont South near 680	480.5	1.7	2.0	3.6	-	11
4	★ Washington Blvd (Your Home)	469.0	1.9	2.2	4.1	62	12
5	Fremont - Glenmoor	483.5	1.6	2.2	2.9	-	12
6	Fremont - PaseoAtDriscoll	623.0	2.9	2.2	4.2	-	12
7	San Jose Willow Glen	628.0	2.7	2.6	4.6	-	14
8	Fremont - MSJE near Park	546.0	2.0	2.6	4.3	78	14
9	Cupertino	399.0	1.2	2.9	4.2	82	16
10	Fremont - Paseo Padre	463	2.2	3.6	5.4	-	20
11	Bangalore	873.5	4.9	3.7	8.4	-	21
12	SF - Metropolitan 2	660.0	3.0	3.9*	4.5	-	22*
13	Cupertino 2	3030.0	8.7	10.3*	10.8	-	53*

Air Quality Metrics - Last 24 Hours

Time range ━ Washington Blvd · Your home

PM2.5 charts show uncorrected sensor readings. Humidity-corrected home values appear above as new data arrives.

Individual readings. Hover over a line for details.

Understanding the Data

Particulate matter (PM) can come from traffic, smoke, dust, and other sources. These measurements do not identify the source:

Count ≥ 0.3 µm: Reported particle count at or above 0.3 micrometers; this is not an ultrafine particle measurement (below 0.1 µm).
PM1.0: Particles ≤ 1 micrometer
PM2.5: Fine particles ≤ 2.5 micrometers (main AQI measure)
PM10: Particles ≤ 10 micrometers, including fine and coarse particles
VOC: Volatile Organic Compounds index

AQI Ranges (based on PM2.5):

0-50: Good (Green) - Generally low risk
51-100: Moderate (Yellow) - Acceptable
101-150: Unhealthy for sensitive groups (Orange)
151-200: Unhealthy (Red)
201-300: Very Unhealthy (Purple)
301+: Hazardous (Maroon)

AQI conversions beside latest readings use individual PM2.5 samples, not a 24-hour average or EPA NowCast. Use the daily summary for the rolling average estimate. PM2.5 alone does not establish overall air quality, and category boundaries are not guarantees of safety.

Barkjohn 2021 US-wide PurpleAir correction: 0.524 × CF=1 PM2.5 − 0.0862 × sensor humidity (%) + 5.75, floored at zero. This is the original linear model, not AirNow's extended correction for extreme smoke.

EPA PM2.5 AQI categories and 2024 breakpoints

🌿 Washington Blvd Air Quality Monitor

Current Air Quality at Your Home

Air Quality Summary · Last 24 Hours

Latest Readings by Location

Current PM2.5 Comparison

Air Quality Metrics - Last 24 Hours

Understanding the Data

Regional Air Quality · PurpleAir Map