Hi Arja，
For the co2 working below -10 degree C, we do not have the data as well. You can contact Sensirion about the detail. thanks.
Sensirion AG
Laubisruetistr. 50
CH-8712 Staefa ZH
Switzerland
phone: +41 44 306 40 00
fax: +41 44 306 40 30
[email protected]
www.sensirion.com