Healthy response to heat and pollen in a changing climate (GoHot)

Introduction

Deaths and disease on a large scale as a result of exposure to heat, pollen and air pollution look likely to increase as climate change progresses

In June 2023, which saw record high temperatures, there were almost 900 excess deaths in the Netherlands. The heat was accompanied by exceptionally high grass pollen counts and poor air quality. This unhealthy mix might have been a factor in the extra high mortality seen that month. It was not only the Netherlands that experienced health problems. In 2023 extreme heat cost the lives of an estimated 47,000 Europeans. As climate change progresses, such health risks will probably increase even further.

Coping with heat stress

Much remains uncertain about what situations are the most dangerous and who is most at risk of illness or death, both now and in the future. Nor is it clear who should undertake what action, and how to prevent the solution to one problem from making another one worse. Recommendations on preventing heat stress, such as ventilation, can for example increase exposure to pollen and poor-quality air.

Objective

The project aims to contribute and implement knowledge to reduce health risks from heat and pollen and to communicate this knowledge in an effective way to vulnerable people and relevant organisations. We will address the following research questions:

1. For whom, when, and where does which combination of pollen concentrations, heat, and poor air quality lead to significantly increased health risks and disease burden?
2. How do children aged 3 to 13 months adapt to heat?
3. Which cooling systems can be used by at-risk groups to reduce heat stress, and what is their effectiveness?
4. What is the influence of different forms of ventilation on indoor pollen concentrations?
5. What is the impact of the density of allergenic pollen-producing trees on pollen concentration in the immediate vicinity of the trees?
6. How does physical training status affect heat acclimatization in people, particularly the elderly and children?
7. Which factors influence healthy heat behavior, and how can this understanding help design and shape improved communication to promote healthy behavior during heat waves?
8. How is communication currently conducted with at-risk groups regarding the prevention of allergies and heat-related health issues, what is the effectiveness of this communication, and which strategies can be used to optimize it to reduce health risks and disease burden?
9. How can current advice and measures be adjusted to reduce health risks related to heat, high pollen concentrations, and poor air quality, or a combination of these factors, based on new insights?
10. How should current advice and measures regarding the reduction of health risks related to heat, high pollen concentrations, and poor air quality, or a combination of these factors, be adapted based on new insights while considering different educational levels?
11. Which strategy works best to inform various stakeholders in green policy and management about the importance of planting low-allergen trees?
12. How can the pilot of the spatial birch pollen forecasting model for the Leiden/The Hague region be scaled up to a national level, and how can multiple pollen species be included?
13. How can the output of the real-time pollen monitor, to be acquired by RIVM/LUMC, best be presented to the public?
14. What are the differences in outcomes between the two heat standards (Wet Bulb Globe Temperature and Predicted Heat Strain), and under which conditions (weather, exertion, clothing, vulnerability) do these differences occur? What does this mean for KNMI's heat stress indicator in operational heat risk assessment?
15. How will the timing of the start, peak, and end of the pollen season change under different climate scenarios for the Netherlands, and what pollen concentrations of common ragweed should we expect?
16. How will risks and disease burden due to heat, pollen, and air quality change in space, time, and intensity for different at-risk groups up to 2050, based on the new KNMI climate scenarios and expected social developments?

Method

We execute pilot studies, data collection and processing and literature research. We also want to be able to predict and assess the risks of pollen and heat better and faster, so that appropriate measures can be taken in time.

(Expected) results

• Broadening knowledge regarding (1) which groups are most vulnerable and will experience nuisance during periods of heat and/or high pollen concentrations (2) which (risk) factors can worsen nuisance (air pollution, weather type) (3) how different groups can behave best during heat and pollen exposure (3) how pollen spreads indoors and in streets with different vegetation.
• The project will result in clear action perspectives for (risk) groups in society, healthcare institutions and municipalities during heat and pollen peaks. This means that the knowledge can immediately be used in practice and in policy. Knowledge will also be passed on through education through knowledge institutes. In addition, information days/professional journals will be actively approached to pass on the knowledge.

Publications

• Project information in Dutch.
• Launch of project developing a healthy response to heat and pollen in a changing climate (GoHot) | ZonMw.
• Geen sneeuw maar pollen met kerst – Hoe omgaan met hitte en pollen in een veranderend klimaat? | Nature Today.