El Nino Watch

Air quality (PM2.5, yearly mean)

Mean PM2.5 over the last 365 days from the global CAMS model (the same model for every place), against the WHO 2021 guideline and interim targets.

Hazards

PM2.5 are fine particles (smoke, traffic, industry, dust) that reach the lungs and blood. The yearly mean comes from the CAMS global model so that all places are compared with the same tool; it is a model, not a monitoring station.

The note gives the number of days above the WHO 24-hour guideline (15 µg/m³) and above 37.5 µg/m³. In Europe the place card also shows CAMS pollen (alder, birch, grass, mugwort, olive, ragweed).

Why it matters for Koh Samui

Southeast Asia has a smoke season (February-April) that El Nino makes worse; European villages are usually cleaner but can have pollen seasons.

Thresholds

Yearly mean PM2.5WHO 2021Exposure
<= 5guideline0
5-10interim target 41
10-15interim target 32
15-25interim target 23
> 25above IT-24

Exposure scale: 0 very low, 1 low, 2 moderate, 3 high, 4 very high. Higher = more exposed. The colour of the matrix cell follows the same scale.

Sources

Related

ENSO status now

ONI (NOAA CPC)
+1.80 °C, JJA 2026 (previous +1.39 °C)
RONI (NOAA CPC)
+1.36 °C, JJA 2026
Nino 3.4 weekly (NOAA CPC / OISST)
+3.0 °C anomaly, week of 16 Sep 2026 (SST 29.6 °C)