[xxpor]

Does it say what type of pollutant? PM2.5 is very different from SO2 which is different from O3, etc.

[akor]

No it's just an LED that's either blue, orange, red. I knew it wouldn't give me exact figures (or pollutants) but from what I'd read the "fix" was to get an air purifier or move.

[xiphias2]

SO2 and O3 sensors are very expensive, so almost all sensors made for homes measure PM.

[xxpor]

In that case it's almost certainly the highway. Tires are a massive source of PM2.5.

[akor]

That's my main concern although maybe air pollution from toast / allergens is just as bad.