Seasonal air quality patterns

Air quality is not static. The same city can swing from “Good” to “Unhealthy” within a season — sometimes within a single day. Understanding seasonal drivers helps you interpret what you see on the dashboard.

Winter: trapped pollution

Cold, calm nights often create temperature inversions — a layer of warm air that caps cooler air near the ground. Smoke from heating and vehicle exhaust gets trapped, pushing PM2.5 upward. Morning rush hour under an inversion is a common high-AQI window in many cities.

Spring: pollen and dust

Tree and grass pollen can elevate coarse particle counts. Dry spring winds lift soil dust in arid regions. Pollen is not always captured in AQI the same way as combustion particles, but sensitive individuals still feel the effects.

Summer: ozone

Hot, sunny weather drives ground-level ozone formation from vehicle and industrial emissions. Ozone peaks in the afternoon when sunlight is strongest. You might see good PM2.5 readings but a higher AQI because ozone is the dominant pollutant.

Autumn and fire season

Agricultural burning, wildfires, and household wood heating can produce intense PM2.5 spikes that travel hundreds of kilometres. Smoke plumes create dramatic day-to-day swings that forecasts help you anticipate.

Using forecasts on Aether

Check the hourly and daily forecast before planning outdoor training, travel, or events. Pair the trend with wind direction on the forecast cards — onshore breezes often clean coastal cities, while stagnant high-pressure systems keep pollution in place.