🍃 Air Quality Index (AQI) & PM2.5 Checker
Check real-time Air Quality Index (AQI), PM2.5 fine particulates, PM10, Ozone, and nitrogen dioxide levels for any city worldwide. 100% free.
Free No Signup Required Browser-Based Live Data
How to Use Air Quality Index (AQI) & PM2.5 Checker
- Type any world city name or click a popular city preset
- Click Check AQI
- View the real-time US AQI score, pollution category, health recommendations, and PM2.5/PM10 breakdown
📖 Technical Encyclopedia & Standards Reference
Check real-time Air Quality Index (AQI), PM2.5 fine particulates, PM10, Ozone, and nitrogen dioxide levels for any city worldwide. 100% free. This tool computes outputs according to official open technical and scientific specifications.
✓ Open Standards AlignmentCompliant with ISO/IEC, W3C, NIST, and standard mathematical formulations.
✓ 100% Client-Side / SecureZero server logging. Computations execute entirely in your local browser sandbox.
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Frequently Asked Questions
What is the Air Quality Index (AQI)?
The Air Quality Index (AQI) is a standard scale from 0 to 500 measuring atmospheric pollutants. Values 0–50 are Good, 51–100 Moderate, 101–150 Unhealthy for Sensitive Groups, and 151+ Unhealthy.
Why is PM2.5 particulate matter hazardous?
PM2.5 particles are microscopic fine particles (≤2.5 micrometers) that can penetrate deep into the lungs and bloodstream, exacerbating respiratory and cardiovascular conditions.