1) Where and when did stations deviate from their own normal? Q1
Each cell is one station-day. Color shows how far that day's PM2.5 sat above (orange–red) or below (blue) that station's own typical baseline — not a citywide average. The wildfire-smoke window (Aug 15–25) should stand out as a solid red band at ST05, ST06 and ST07.
2) Which stations stay elevated year-round? Q2
Mean PM2.5 in Winter (Dec–Feb) vs. Summer (Jun–Aug) for each station. Every station falls from winter to summer — but the three wildfire-affected stations (red) fall noticeably less, because their August spike partly offsets the normal seasonal dip.
3) Does smoke break the usual NO2–PM2.5 relationship? Q3
Each point is one station-day: traffic-linked NO2 vs. PM2.5. Two fitted trend lines compare normal days to wildfire-smoke days — a separated, higher red line means smoke behaves like "extra" PM2.5 that traffic alone does not explain.