[x3iv130f]

For home use, you should aim for multiple sensors that can track temperature, humidity, CO2, VOC, and PM2.5.

CO2 is important to track as high concentrations can impact sleep quality and critical thinking ability.

VOCs is important to track as they are associated with asthma and allergic reactions.

CO2 can only be removed by opening a window.

Most VOCs come from household chemicals and are only removed by using lots and lots of charcoal filters as the HEPA filters in household air purifiers aren't able to capture it in significant amounts.

[stephen_g]

CO₂ can also be removed with mechanical ventilation, of course. Preferably heat- or energy-recovery ventilation to pre-condition the outside air being brought in, so you're not just dumping the air you expended energy heating or cooling straight out!

[rnk]

I like that but I also want to measure carbon monoxide making into my house and propane or natural gas leaks. What sensor does that also?

[Eisenstein]

The problem is that carbon monoxide sensors degrade, so any sensor that incorporates one will have a limited life.