Several backpacking groups in the Canadian Rockies took readings daily. Those field readings were compared to the Environment Canada air quality ratings for those same days.
What we found was that daily readings in the field varied widely compared to the EnvCan ratings. Even morning to evening the field readings had big swings. This was confirmed by guides with relative visual smoke. The EnvCan nearest readings were in Calgary - 80km away, and well downslope from the mountains, hence their more consistent ratings.
What this means: as a decision maker I sit at my desk and rely upon EnvCan air quality ratings that are likely being taken a distance from where my groups are. In-field readings show promise, but will need to be tied to new ideas around local decision making. What do we expect guides to do with high pm2.5 readings? Additionally, the portable monitors realistically only put a number on what guides could see and smell already. There may be simpler visual cues that we can articulate to assess air quality on-the-spot.
Stay tuned -early days on development of this.