Direct air-quality answer
Why do air-quality apps disagree?
Air-quality apps often disagree because they are not showing like-for-like data. One may use European AQI and another U.S. AQI; one may show a station and another a model; their locations, valid times, averaging periods, pollutants, or refresh cycles may also differ.
Compare the metadata
45
European AQI · model · 14:00
90
U.S. AQI · station · 13:00
Numbers without context are not equivalents
Short answer
Air-quality apps often disagree because they are not showing like-for-like data. One may use European AQI and another U.S. AQI; one may show a station and another a model; their locations, valid times, averaging periods, pollutants, or refresh cycles may also differ.
A difference does not prove that either screen is fabricated. It means the metadata must be aligned before the numerals can be compared fairly.
The most common sources of disagreement
OpenWeather scales use different breakpoints. A model grid and point monitor represent different spaces. A forecast valid hour is not the same as the latest station observation. Apps may snap a place name to different coordinates.
Caching also matters: one service may have a new model run, another may show a labeled stale result, and another may be unavailable.
How AirAgora handles the question
AirAgora names the OpenWeather 1–5 scale, source, modeled status, location, provider update, valid hours, completeness, and stale state. It uses explicit ambiguity selection for same-named cities.
The production adapter never hides a provider failure behind fixtures, scraping, or another provider. This may produce an unavailable screen where another app displays something older or differently sourced.
What to check before comparing
Compare scheme, pollutant, aggregate versus component, unit, valid time, issue time, timezone, coordinates, source type, and refresh time.
During a severe official event, use the relevant authority instead of attempting to choose a winner among consumer apps.
- Different OpenWeather scales
- Model versus station
- Different coordinates
- Different valid or issue times
- Different cache and refresh states
Direct answers
Frequently asked questions
Can equal AQI numbers mean different things?
Yes. European and U.S. AQI use different category structures.
Can apps choose different locations for the same city?
Yes. Geocoding, centroids, device coordinates, and station selection can differ.
Does a newer page mean newer data?
Not necessarily. Check the underlying source or model timestamp.
How does AirAgora make comparison easier?
It shows scheme, modeled provenance, source time, selected place, completeness, and stale state.
Does AirAgora treat “Why do air-quality apps disagree” as a personal guarantee?
A difference does not prove that either screen is fabricated. It means the metadata must be aligned before the numerals can be compared fairly.
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.