Haze & air quality
Haze cuts visual line of sight even on a calm, dry day - often the factor pilots forget to check.
Reading Malaysia's API bands as a drone pilot
Malaysia reports air quality as the Air Pollutant Index (API). The official bands are 0–50 Good, 51–100 Moderate, 101–200 Unhealthy, 201–300 Very Unhealthy, and above 300 Hazardous. Those bands describe a health risk, not a flying risk, so this page maps them to what they mean for keeping a drone in visual line of sight:
| API | Band | What it means for flying |
|---|---|---|
| 0–50 | Good | Full visibility. Haze is not a factor. |
| 51–100 | Moderate | Slight haze possible; visibility normally still fine for VLOS. |
| 101–200 | Unhealthy | Visibility measurably reduced - fly closer in and keep a stronger visual watch. |
| 201–300 | Very Unhealthy | Not recommended. Visibility and health risk both significant. |
| 300+ | Hazardous | Do not fly. |
When is haze worst in Malaysia?
Haze in Malaysia is irregular rather than a fixed season - it depends on transboundary fire activity and wind patterns, and can spike within days. It is most often a problem during the drier southwest monsoon period, roughly June to September, and affects Peninsular Malaysia more than Sabah and Sarawak. Because it can arrive fast, check it per-flight rather than assuming a time of year is safe.
PM2.5, PM10 and AOD
PM2.5 and PM10 are ground-level particulate concentrations in µg/m³ - PM2.5 is the finer fraction and the one that most reduces contrast and visible range. AOD (aerosol optical depth) is a satellite-derived measure of how much haze sits in the whole air column above you; a high AOD with modest ground PM often means smoke aloft, which still degrades aerial image quality even when the ground looks clear.
Figures here are modelled estimates from CAMS via Open-Meteo, refreshed hourly - not official APIMS station readings. For a health-sensitive decision, cross-check Malaysia's Department of Environment APIMS portal.