WIREDGOV

A spell of warm, dry and sunny weather has led to rising pollen levels across much of the UK this week.

These conditions are particularly favourable for pollen release and dispersal, meaning many people are likely to notice an increase in hay fever symptoms. While some changes in the weather later in the week may ease pollen levels slightly, high or very high levels are expected to persist for several days, especially in central and southern areas.

This week also marks a key point in the tree pollen season, with birch pollen becoming increasingly dominant, alongside ongoing ash pollen and the early beginnings of oak pollen.

Why pollen levels are high this week

Weather plays a crucial role in both how much pollen is produced and how effectively it spreads. The recent pattern of warm temperatures, sunshine and dry conditions has encouraged trees to release pollen in large quantities. In addition, breezy conditions help pollen grains disperse more widely and remain airborne for longer, increasing exposure.

Warm conditions stimulate pollen development within catkins, while dry air allows pollen to be released more easily. Without rainfall to wash pollen out of the air, levels can steadily build from day to day, which is what many people are experiencing now.

Pollen levels are currently at their highest this week and are expected to remain high, or even very high, through to Friday. Falling temperatures and the increasing risk of showers into the weekend may help reduce levels slightly, but high pollen levels are still possible, particularly during any dry and bright spells.

Which pollen types are affecting people now

We are currently in the middle of the birch and ash pollen seasons. Birch pollen is now becoming the dominant type and tends to affect a large number of people, often causing more widespread symptoms than ash. Ash pollen levels have already been high, particularly in southern parts of the UK, and the peak is now gradually shifting northwards.

Oak pollen is also just beginning to emerge. While it has not yet reached peak levels, it can still contribute to symptoms, especially for people who are sensitive to multiple pollen types.

Plane pollen may also be present, particularly in urban areas where plane trees are commonly planted. Although it affects fewer people overall, it can still be a trigger for some individuals.

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