How to tell if your air quality data is actually reliable
Your state EPA website offers the most accurate air data; many apps mix different sources and need checking.
Your state Environmental Protection Authority website offers the most accurate air data. Government monitoring networks use reference instruments, highly precise devices regularly checked and maintained.
Mobile apps often re-purpose this data, but some mix in cheaper networks like IQAir or PurpleAir. Low-cost networks give rough estimates rather than exact readings.
The same location can show different results across apps. Before trusting an air quality app, ask four questions.
Who runs it, government, university, research body, company or community? What data are they showing, primary or secondary?
What instruments do they use, reference grade or indicative? What quality control is in place, such as maintenance and calibration?
Cheaper monitors help fill gaps but require careful upkeep. Without maintenance, readings drift.
If an app can't answer these questions clearly, use it as a rough guide only.
- IQAir and PurpleAir
- Low-cost networks
- Hourly
- Update frequency
Why it mattersApps can show different readings for the same location, so checking data quality helps you choose the most reliable source.
