California, United States. Measured by low-cost sensors, too few to rank; the model estimate below is the cross-check.
24-hour average, not ranked26US AQI
1–2 sensors, not rankedGood
PM2.5 4.7 µg/m³, 0.3× the WHO 24-hour guideline, from the one low-cost sensor in Milpitas. One cheap unit can read well off, so Milpitas isn't ranked.
7-day average: 54 US AQI (10.5 µg/m³)
Latest hour: 17 US AQI (3.0 µg/m³), local time
The model's estimate for the same 7 days is about 9 µg/m³: the two agree.
Measured, but by one low-cost sensor and no other monitor. It passes the same checks as every sensor we count (stuck, frozen, spikes, far from the model), yet one unit can still be off. A third sensor here would rank Milpitas. How sure each figure is
Hour by hour
Hourly values over the last 4 days, local time. Dashed line: WHO 24-hour guideline (15 µg/m³).
Last 30 days
One cell a day, coloured by its band: 5 of 30 days had 18 hours or more of readings. Grey: not enough.
The model's estimate
7-day average, estimated≈ 9µg/m³
Estimate, not measuredLikely good to moderate
Likely between 6 and 13 µg/m³ (33–58 US AQI): the model's 7-day average to 12 Oct 2026, about 0.6× the WHO 24-hour guideline.
30-day average, estimated: ≈ 8 µg/m³
Model estimate from the Copernicus Atmosphere Monitoring Service (CAMS), scaled by 0.59 to match 10 cities within 300 km measured by reference monitors over the last week. Adjusted this way, a single day lands within ×1.5 of what a monitor would read about two times in three: a guide, not a measurement. Not ranked on SmogRank's boards.
Last 30 days, estimated
Daily means, UTC days. Dashed line: WHO 24-hour guideline (15 µg/m³).
Estimates contain modified Copernicus Atmosphere Monitoring Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains. How estimates are made.
Use this page
SmogRank, estimated PM2.5 daily means (CAMS model estimate, not measured), Milpitas, United States, 13 Sep 2026 – 12 Oct 2026, smogrank.com/us/milpitas (accessed 14 Oct 2026). Contains modified Copernicus Atmosphere Monitoring Service information 2026.
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
