# FLEX temperature and VOC units

**URL:** <https://community.purpleair.com/t/flex-temperature-and-voc-units/22916>\
**Category:** Sensors\
**Created:** [September 9, 2026, 11:00am UTC](https://community.purpleair.com/t/flex-temperature-and-voc-units/22916 "2026-09-09T11:00:31Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![OU\_livinglab](https://avatars.discourse-cdn.com/v4/letter/o/49beb7/32.png) [@OU\_livinglab](https://community.purpleair.com/u/OU_livinglab)\
**Post date:** [September 9, 2026, 11:00am UTC](https://community.purpleair.com/t/flex-temperature-and-voc-units/22916/1 "2026-09-09T11:00:31Z")

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Hello,  
Is it possible to change the default temperature units on a FLEX so that the temperature that is displayed on the map, saved to the SD card and for API download to degrees celsius (˚C)? I’m using this for educational purposes outside the US, so wish to a) demonstrate good practise (i.e. using SI units), and b) understand the readings when viewing the live data. We don’t use ˚F.

Also, what are the units of the VOC measurements? I assume this is the column ‘gas’ in the SD data file?

Thanks

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<div class="post-metadata">

**Author:** ![Andrew\_Meiners\_PA](https://sea2.discourse-cdn.com/flex020/user_avatar/community.purpleair.com/andrew_meiners_pa/32/9963_2.png) [@Andrew\_Meiners\_PA](https://community.purpleair.com/u/Andrew_Meiners_PA)\
**Post date:** [September 24, 2026, 10:29pm UTC](https://community.purpleair.com/t/flex-temperature-and-voc-units/22916/2 "2026-09-24T22:29:13Z")

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You can display temperature in Celsius on the PurpleAir map, but the Flex’s SD card and API temperature fields remain in Fahrenheit. On the map, open the configuration menu, set Preferred Units to Metric, and select the Temperature °C data layer. The [PurpleAir Map Guide](https://community.purpleair.com/t/purpleair-map-guide/90) describes these settings.

The SD card records temperature in the `current_temp_f` column, and the API temperature fields also report degrees Fahrenheit. These units cannot be changed on the Flex. To use Celsius in your analysis, convert the downloaded values with `(°F - 32) × 5 ÷ 9`.

These values are measured inside the Flex housing and can read warmer than the surrounding air. The [Understanding SD Card Data Columns](https://community.purpleair.com/t/understanding-sd-card-data-columns/279) and [API Fields Descriptions](https://community.purpleair.com/t/api-fields-descriptions/4652) articles provide the field definitions.

Yes, `gas` is the VOC field in the SD card data. It is reported in Bosch Static IAQ units, not as a concentration such as ppm or ppb. PurpleAir considers these readings experimental. They do not identify individual compounds or use a health-based scale. [What Do PurpleAir Sensors Measure and How Do They Work?](https://community.purpleair.com/t/what-do-purpleair-sensors-measure-and-how-do-they-work/3499) explains the VOC output in more detail.

Please let us know if you have any other questions.