San Jose Air Quality Alert: PM2.5 Levels Reach Unhealthy for Sensitive Groups

Source: EPA · San Jose, CA

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On February 21, 2026, air quality in San Jose, CA reached an AQI of 107 for PM2.5, categorized as Unhealthy for Sensitive Groups.

What this EPA air-quality advisory tells you, and what most readers miss

This notice was issued by EPA on February 23, 2026 and geographically references San Jose, CA. Its severity classification of "low" signals how the issuing agency weighs the risk of harm if no action is taken — "critical" and "high" tier alerts typically carry direct consumer actions, while "medium" and "low" tend toward informational guidance or monitoring advisories. The category it belongs to — Air Quality — determines the regulatory framework behind it, which shapes what remedies (refunds, replacements, recalls, evacuations) are available to affected individuals and who holds statutory responsibility for enforcement.

Most readers skim a notice like this, check whether they are personally affected, and move on. The more useful lens is to read it as a data point about the issuing system: how quickly EPA detected the hazard, how precise the geographic or product-identifier scope is, and whether similar notices have clustered in the same category or region in the last 90 days. Cluster patterns frequently precede a broader regulatory action — a single localized EPA air-quality advisory is isolated; three of them within a quarter often indicate a supply-chain, infrastructure, or seasonal driver that will keep producing notices until something structural changes.

For decision-making, Areazine pairs each alert with the original agency URL, the full agency name, and a timestamp so you can verify the notice against the primary source before acting on it. Tags on this item (air-quality, epa, aqi, San Jose) map to related alerts in the same area of risk — browsing them together gives a clearer picture than any single notice alone, because the shape of an ongoing issue only becomes visible across multiple sequential alerts.

Current Air Quality

In San Jose, CA, the air quality was monitored on February 21, 2026. The primary pollutant of concern is fine particulate matter (PM2.5), which recorded an Air Quality Index (AQI) of 107, falling into the "Unhealthy for Sensitive Groups" category. Ozone (O3) levels were also measured at an AQI of 36, which is categorized as "Good."

What This Means

An AQI between 101 and 150 is considered "Unhealthy for Sensitive Groups." At this level, members of sensitive groups may experience health effects, though the general public is less likely to be affected.

Who Should Take Precautions

Groups at higher risk include people with heart or lung disease, older adults, children, and teenagers. These individuals are more sensitive to the effects of fine particulate matter (PM2.5).

What You Should Do

Sensitive groups should reduce prolonged or heavy outdoor exertion. It is recommended to take more breaks and engage in less intense outdoor activities. Watch for symptoms such as coughing or shortness of breath. The general public does not need to take special precautions at this AQI level.

Source

Data attributed to EPA AirNow.

Original source: EPA Official Notice ↗

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Frequently Asked Questions

Common questions about this EPA air-quality advisory.

What is this EPA air-quality advisory about?
On February 21, 2026, air quality in San Jose, CA reached an AQI of 107 for PM2.5, categorized as Unhealthy for Sensitive Groups.
Which agency issued this alert?
This alert was issued by EPA. The original notice is available at the source link at the bottom of this article.
How severe is this alert?
This alert is classified as "low" severity. No immediate action required, but stay aware.
What area is affected?
This alert affects San Jose, CA. Check with EPA for the most current geographic scope.
Where can I find more Air Quality updates?
Browse the full Air Quality feed on Areazine at areazine.com/air-quality/ for the latest updates from EPA and other agencies.