Is it possible to use VOC index instead of TVOC?

[RASTRILL0]

Is your feature request related to a problem? Please describe.

The SGP40 and SGP41 gas sensors report VOC as an index. The index is unit-less and bounded between 0–500 steps from the best to the worst air quality level. These sensors are pretty good at detecting VOC in realistic lab tests (see Al-Okby et al, 2022: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8876806/ ). Table 1 in the linked paper offers an approximation of TVOC levels compared to the VOC index values reported by the SGP4X sensors.

Describe the solution you'd like Suggest adding a new unit to tvoc in ha-iaquk called 'index' that converts index values and corresponding PPM values to determine the TVOC placement on the IAQUK rating index.

Describe alternatives you've considered I could try to manually add a template sensor to HA configuration.yaml to create a surrogate TVOC from VOC Index but I think with the popularity of these sensors, it might make more sense to solve the issue in the project itself.

Additional context

[Limych]

@RASTRILL0 Test it, please.

[RASTRILL0]

Sorry for the delay. Got a chance to try it out today and everything seems to be working great. Thanks so much!