Air · PM2.5
WHO AQG 2021 · fine particles, µg/m³
0–5WHO annual target · forest after rain
5–15within WHO 24h · normal urban background
15–35above WHO 24h · roadside, light traffic
35–55sensitive groups affected · near a fire
55+unhealthy for everyone · indoor cooking smoke
Noise · WHO 2018
40 dB night / 30 dB indoor
Chronic exposure above 40 dB at night is linked to cardiovascular strain and broken sleep.
Heat · tropical context
33+ °C with >70% RH
The heat-stress threshold for outdoor workers — not Europe's 24°C comfort band.
Humidity · mould risk
>60% RH sustained
Also the window where Aedes mosquitoes breed fastest. Indoor air matters as much as outdoor.