Air quality readings stay inside the seasonal band at most sites
The daily index at twenty-one of twenty-four sites came in below the median for the same period in previous years. Three sites sit above the median but within the usual spread.
| Site | Index | Median | Delta |
|---|---|---|---|
| DK-14 | 31 | 38 | −7 |
| NB-03 | 27 | 35 | −8 |
| EK-21 | 44 | 41 | +3 |
| SV-05 | 29 | 36 | −7 |
| B-07 | 22 | 30 | −8 |
The median is computed over the same calendar day across the previous five years.
The steady westerly transport of the past week explains most of the picture: the surface layer mixes better than during the calm spells of early August.
Site EK-21 remains the exception. It sits closer than the others to a transport junction, and its daily profile has always followed traffic: a rise toward eight in the morning and a second, weaker one toward seven in the evening.
How to read the index
The index is a composite value, not a measurement of any single substance. It is useful for comparing sites and comparing days, but it does not replace the primary measurement series published by the network owner.
We publish the index without recomputation or smoothing. If the publishing party later revises a value, we update the table and note it in the corrections section.