With the change in climate, people are more exposed to allergens from pollen, moths and the dust mite. Allergens are substances that can trigger allergic reactions, such as hay fever. Approximately 15 to 20 percent of the Dutch population suffers from allergic symptoms. For this reason, the impact of climate change on health effects due to allergens is considerable.


Pollen in the air can cause hay fever. Pollen comes from grasses, trees and herbs. With higher temperatures, the flowering season starts earlier, lasts longer and there are more pollen. New species of plants or trees can also become established, such as Ambrosia. As air circulation changes, so does dispersal. This can lead to a longer and more intense pollen season. In addition, the effect of pollen is amplified by air pollution. For more information, also visit the KNMI website.

Oak processionary moth

Another culprit for allergic reactions is the oak processionary moth. This moth has spread throughout the country in recent years. The hairs of the moth are poisonous. You get itching, bumps, red eyes or allergic reactions, such as shortness of breath, fever, swelling and vomiting. Every year, about 80,000 people develop health problems. Due to climate change, the number of complaints may increase during the infestation season (June, July and August). Other species, such as the pine processionary moth, may also start to occur in the Netherlands. To reduce the nuisance, the Knowledge Platform Processionary Moth was established.

House mite and mould

Climate change also affects indoor temperature and humidity. Higher temperatures and humidity enable molds and dust mites to develop better. Moisture and mold contribute to the development and worsening of asthma. Particularly in urban areas. This is because the temperature rise is greatest in cities and there are many older homes. These homes have poorer temperature and humidity control systems.


There are several ways to reduce the impact of allergens:

  • Finding out which pollen someone is allergic to and then providing appropriate treatment;
  • Developing a monitoring system so that patients are warned in time if there is a risk of pollen;
  • Tackling air pollution in urban areas;
  • Taking account of greenery that causes allergens when designing green spaces in cities;
  • Addressing moisture problems in old homes.