Spain Braces for Longer, More Intense Allergy Seasons: What You Need to Understand
Around eight million people in Spain dread the approaching end of winter, as it signals the start of allergy season. Experts have observed not only increasing severity but also an earlier onset of symptoms. A recent Spanish study analyzing the relationship between pollen and meteorological data sheds light on these changes.
Pollen Seasons are Expanding
Researchers at the University of Córdoba (UCO) studied daily pollen concentrations over 23 years (2001-2023) and discovered that flowering now begins earlier and ends later – almost four days each year. This means the pollen season in Spain now lasts 100 days longer than it did 25 years ago.
The Role of Wind and Weather Patterns
Previous studies have indicated that meteorological variables can extend the pollen season. This research confirms that wind is a key factor in understanding variations in pollen levels. The study utilized calculations of air mass back trajectories to understand how wind patterns influence pollen distribution.
The influence of wind is noticeable in both phases of the pollen season: before and after the peak concentration of pollen in the atmosphere. Gentle winds and short air mass trajectories favor pollen accumulation near its source. Conversely, stronger winds help concentrate pollen initially and promote greater dispersion later in the season.
“Once the pollen is in the atmosphere, the wind is the main agent conditioning its dispersion,” explains Miguel Ángel Hernández, a researcher at the UCO and lead author of the study.
Grass Pollen: The Primary Culprit
The lengthening season is particularly concerning because grass pollen is the most frequent cause of respiratory allergies. The behavior of grass pollen varies depending on weather conditions and geographical location.
Rainfall and Pollen Fragmentation
Abundant autumn rainfall can prevent some plant species from drying out as quickly, potentially impacting the following season’s pollen release. Recent record-breaking rainfall may therefore “affect the pollen season.”
Intermittent rain fragments pollen into microparticles that remain airborne longer, increasing allergy intensity. When pollen contacts humid air, it absorbs water, causing its membrane to rupture and release hundreds of allergenic protein-laden microparticles. These smaller particles stay suspended in the air for extended periods, even without wind.
Looking Ahead: Anticipating Future Scenarios
Understanding how pollen dynamics vary throughout the season helps in preventing and managing allergy seasons more effectively. Researchers are “characterizing the past to try to anticipate future scenarios.” Analyzing wind patterns historically can help predict how grass pollen will behave during specific weather events.
The influence of wind isn’t solely about intensity but also its origin. Air from the Mediterranean typically results in less severe allergy episodes than air from the west.
Some studies in northeastern Spain suggest that pollen dynamics are significantly influenced by meteorological conditions, including wind, which can redistribute fallen pollen.
What to Expect This Season
It’s still too early to predict the severity of this spring’s allergy season. Last year’s season was particularly severe due to heavy rainfall. Prolonged rainfall is likely to impact this year’s pollen season.
“We are going to have an intense season with high concentrations of pollen,” predicts Hermina García, a researcher at UCO. “And if the weather during the spring is favorable, it will also lengthen it.”
Frequently Asked Questions
Q: What is the main cause of respiratory allergies in Spain?
A: Grass pollen is the most frequent cause of respiratory allergies.
Q: How does wind affect pollen levels?
A: Wind disperses pollen, influencing both the accumulation and spread of allergens.
Q: Does rainfall impact allergy season?
A: Yes, intermittent rainfall can fragment pollen into smaller, more allergenic particles that stay airborne longer.
Q: Is the allergy season getting longer?
A: Yes, the pollen season in Spain now lasts 100 days longer than it did 25 years ago.
