# How is hourly historical purpleair data generated?

**URL:** <https://community.purpleair.com/t/how-is-hourly-historical-purpleair-data-generated/4217>\
**Category:** API\
**Created:** [April 14, 2023, 9:20pm UTC](https://community.purpleair.com/t/how-is-hourly-historical-purpleair-data-generated/4217 "2023-04-14T21:20:50Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![amukherj](https://avatars.discourse-cdn.com/v4/letter/a/c37758/32.png) [@amukherj](https://community.purpleair.com/u/amukherj)\
**Post date:** [April 14, 2023, 9:20pm UTC](https://community.purpleair.com/t/how-is-hourly-historical-purpleair-data-generated/4217/1 "2023-04-14T21:20:50Z")

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Hi folks,

I have been working with hourly historical purpleair data through the “Get Sensor History” pathway. I have questions about how is this data generated such as:

- Are there any quality control steps that are applied in going from raw data to hourly data, such as completeness requirements?

- Are there any correction factors applied to “pm2.5\_cf\_1” and “pm2.5\_atm” fields?