Skip to main content

How are Individual and aggregated (1-hour mean, 24-hour mean, ...) measurements calculated and what is their timestamp on Dashboard?

The Dashboard lets you view and download both individual readings and several aggregated averages. This article explains how each one is calculated and how it's timestamped, so you know exactly what a value represents.

Individual measurements​

These are the highest-resolution measurements — single readings from a Node-S. They're timestamped to the exact moment they were recorded, for example 12:56:21 UTC.

Note: Unlike aggregated measurements, individual measurements aren't reported on a fixed cadence, because the Node-S reporting interval can vary. For more, see sampling frequency.

1-hour mean​

The average of all individual measurements collected during a specific UTC hour. For example, the 04:00 UTC 1-hour mean aggregates everything measured between 04:00:00 and 04:59:59 UTC.

24-hour mean​

The average of all measurements collected over a complete UTC day. For example, the 24-hour mean for 2024-01-01 aggregates all measurements from 00:00 UTC to 23:59:59 UTC that day.

NowCast and 24-hour rolling mean​

These use different time windows and are reported hourly, giving you specialized views of air quality trends:

  • NowCast aggregates measurements over a 12-hour window following the US EPA NowCast calculation rules, ending at the end of the reporting hour. For example, a PM2.5 NowCast timestamped 16:00 UTC includes data from 05:00 UTC to 16:59:59 UTC.
  • 24-hour rolling mean averages measurements over a sliding 24-hour window, also ending at the reporting hour.

What's next​

Was this article helpful?​

Yes, thanks! / Not really

Still need a hand? Email us at support@clarity.io or create a support ticket, and our team will get back to you.

Last updated on