Direct planning answer
Why does AQI change by hour?
Hourly AQI changes because the underlying pollutant conditions and modeled forecast fields change over time. The aggregate can also switch which pollutant component controls the index. A new model run or updated observation can revise the displayed pattern.
Four clocks
Short answer
Hourly AQI changes because the underlying pollutant conditions and modeled forecast fields change over time. The aggregate can also switch which pollutant component controls the index. A new model run or updated observation can revise the displayed pattern.
A change in the app does not necessarily mean the air changed at the exact moment of refresh. It may reflect a new source run, valid hour, station report, cache state, or location selection.
The index follows pollutant-specific inputs
Pollutants can have different hourly patterns, and AQI applies scheme-specific rules to their components. The aggregate generally follows the component with greatest concern.
Weather and emissions influence atmospheric conditions, but AirAgora does not infer a local causal story from a city forecast. It reports the fields and provenance it receives.
How AirAgora answers
AirAgora compares consecutive valid hours with a fixed score, stores the source timestamp, and uses stable ties. It does not smooth missing hours or overwrite an old provider timestamp with page-view time.
Alerts distinguish a true threshold crossing from remaining above the same threshold. Recovery and cooldown state prevent a message on every scheduled run.
How to use the answer
Compare the same OpenWeather scale, pollutant, location, valid hour, and source run. Determine whether the screen is modeled, observed, or cached.
A sharp official local event should be checked against public warnings and monitoring information rather than interpreted solely through one forecast curve.
- Underlying pollutant fields change
- Controlling component can change
- Model runs revise forecasts
- Valid time differs from refresh time
- Cache and source must be labeled
Direct answers
Frequently asked questions
Does every refresh create a new AQI?
No. The app may reuse a valid cache or the provider may still serve the same model run.
Can the main pollutant change by hour?
Yes. Compatible pollutant components can change relative order.
Does an AQI jump prove a local incident?
No. It may reflect source updates, location, model behavior, or real conditions; separate evidence is needed for a cause.
Will alerts repeat for every high hour?
Crossing state, recovery, cooldown, and idempotency are designed to prevent repeated sends.
Does AirAgora treat “Why does AQI change by hour” as a personal guarantee?
A change in the app does not necessarily mean the air changed at the exact moment of refresh. It may reflect a new source run, valid hour, station report, cache state, or location selection.
Evidence register
Sources and further reading
The links below identify the primary references used on this page. Selection, summary, and presentation are AirAgora modifications.
Keep exploring
AirAgora provides informational planning guidance, not medical advice. Local conditions can differ from modeled forecasts; follow official guidance during severe events.