Pollen types in Europe
Copernicus forecasts six pollen types across the European domain. They do not overlap much: between them they cover the year from alder in January to ragweed in October, and each one dominates a different part of the continent.
Mar–May
The defining spring allergen of northern and central Europe, and one of the most potent: a single tree releases pollen in the hundreds of millions, and grains travel hundreds of kilometres on the wind. Its allergen cross-reacts with apple, cherry and hazelnut, which is why so many birch-allergic people also get an itchy mouth from raw fruit.
Strongest across Scandinavia, the Baltic states, Poland, Germany and the British Isles. Thins out around the Mediterranean, where birch does not grow well.
May–Sep
The most widespread pollen allergy in Europe, and the one that affects the most people — grasses grow everywhere from Portugal to Finland, so nowhere on the continent has a grass-free season. Counts are lower than birch's but the season is far longer, running most of the summer.
Everywhere. There is no part of the domain without a grass season, though the timing shifts by about a month between south and north.
Jan–Apr
The first pollen of the year, often airborne in January while everything else is still dormant. It belongs to the same family as birch and shares its allergens closely enough that most people allergic to one react to the other, which effectively extends the birch season backwards by two months.
Much the same range as birch, with the highest counts in central Europe and around waterways, where alder grows.
Jul–Sep
A late-summer weed of roadsides and waste ground, potent enough to cause symptoms at counts a tenth of what birch needs. It overlaps with ragweed and cross-reacts with it, and also with celery, carrot and several spices.
Central and eastern Europe, from Germany eastwards, and common through the Balkans.
Apr–Jun
Confined to the Mediterranean, where it is the dominant spring allergen — in parts of Andalusia, Greece and southern Italy it matters more than birch does in the north. Counts run high: a spring day in an olive-growing region can reach four figures without being remarkable.
Spain, Portugal, Italy, Greece, Cyprus and southern Turkey. Effectively absent north of the Alps.
Aug–Oct
An invasive North American weed that has spread through the Pannonian basin and the Balkans, with a second front in the Rhône valley. It is the most potent pollen on this list — symptoms begin at single-figure counts — and its season runs late, filling the gap between summer grass and the first frost.
Hungary, Croatia, Serbia, Romania and northern Italy above all, and the Rhône-Alpes region of France. Spreading northwards.
Every level band on this site is expressed in grains per cubic metre, the same unit a counting station reports, so the numbers here can be compared directly with a national network's.