- Extended Pollen Season: Rising temperatures are causing plants to flower earlier and for longer periods. This means that pollen seasons are becoming longer, exposing people with allergies to pollen for a more extended time.
- Increased Pollen Production: Higher temperatures and atmospheric carbon dioxide (CO2) levels stimulate plant growth and pollen production. Some studies have projected an increase in pollen production by up to 200% by the end of the century.
- More Potent Pollen: Climate change may lead to an increase in the concentration of allergens per pollen grain. Higher CO2 levels have been linked to increased protein synthesis in plants, including the production of allergenic proteins.
- Changes in Pollen Dispersal: Altered weather patterns, such as stronger winds, can spread pollen over greater distances, affecting individuals who may not have been previously exposed to specific allergens.
- Urban Heat Island Effect: Cities tend to be warmer than surrounding rural areas due to the concentration of buildings and paved surfaces. This "urban heat island" effect can intensify pollen production and worsen hay fever symptoms.
- Increased Exposure to Allergens: With warmer temperatures, people are likely to spend more time outdoors engaging in activities that increase exposure to pollen, such as gardening, hiking, or participating in sports.
- Interactions with Air Pollution: Climate change-related increases in air pollution, such as smog and ozone, can further irritate and inflame the airways, exacerbating hay fever symptoms.
As a result of these factors, hay fever is becoming a more significant public health issue, affecting not only individuals with existing allergies but also increasing the risk of developing allergies in those previously unaffected.
