Around here ozone (O3) is a major outdoor (and sometimes indoor) pollutant, but most monitors don’t seem to include it. PM2.5 might be very low, and O3 very high, or vise-versa. Maybe a thought to add to the outdoor sensor?
So some searching yields O3 sensors that read in the 0-150 ppb range for about $60 in smaller quantities. Their life is about 2 years. O3 pollution is one of the worst out there. O3 Article Maybe worth considering. Yesterday here it was 129 ppb, which is getting bad.