The index is based on a health-related assessment of hourly mean ozone and nitrogen dioxide values and of hourly moving PM10 and PM2.5 daily mean values. For calculating the index, at least one of the four pollutants has to be measured at a station. The lack of measurements of at least one pollutant at a station is indicated by an incomplete circle:
The index is based on all four pollutants
Data incomplete: The index is based on one, two or three pollutants
The latest hourly concentration values of each station are categorized by the following thresholds. The pollutant with the worst index value determines the color of the total index.
| Index | Hourly mean value of NO2 in μg/m³ | Hourly moving daily mean value of PM10 in μg/m³ | Hourly moving daily mean value of PM2.5 in μg/m³ | Hourly mean value of O3 in μg/m |
|---|---|---|---|---|
| very poor | > 200 | > 100 | > 50 | > 240 |
| poor | 101-200 | 51-100 | 26-50 | 181-240 |
| moderate | 41-100 | 36-50 | 21-25 | 121-180 |
| good | 21-40 | 21-35 | 11-20 | 61-120 |
| very good | 0-20 | 0-20 | 0-10 | 0-60 |
Health advice
| Index | Health advice and recommendations |
|---|---|
| very poor | Negative health effects can occur. Those who are sensitive or have pre-damaged airways should avoid physical outdoor exertion. |
| poor | Sensitive persons may experience adverse health effects. They should avoid physically strenuous outdoor activities. In combination with other air pollutants, also less sensitive people may react to this air pollution. |
| moderate | Short-term adverse health effects are unlikely. However, effects of air pollutant combinations and of long-term exposure to an individual pollutant cannot be excluded. Additional irritation, e.g. triggered by pollen, can intensify the effect of air pollutants, so that adverse health effects on sensitive persons (e.g. suffering from asthma) can become more likely. |
| good | Enjoy your outdoor activities, adverse health effects are not expected. |
| very good | Best conditions to spend time outdoors extensively. |
