Por María Izquierdo 
The Ministry of Environment, Housing, and Territorial Planning recommends taking precautions due to the prediction of high concentrations of dust particles in the air coming from North Africa for tomorrow, Friday, May 30, in the southwest area of the Community and during Saturday, May 31, and Sunday, June 1, throughout the territory of Castilla y León. It is advisable to avoid activities that involve physical effort for at-risk groups and sensitive individuals, as well as outdoor burning of plant residues.
May 29, 2025
Castilla y León | Ministry of Environment, Housing, and Territorial Planning
Prediction models announce the intrusion of dust particles from North Africa, which are expected to cause an increase in measured levels of these substances in the air in the southwest area of the Community for tomorrow, Friday, May 30, and throughout Castilla y León on Saturday and Sunday, May 31 and June 1. This is a completely natural process over which there is no human intervention, except for taking precautions to minimize exposure to these particles.
This alert is predictive, as the information is available through air quality models for PM10 particles (particles smaller than 10 microns). The prediction indicates that values may reach above 50 μg/m3 as a 24-hour moving average, determining very unfavorable air quality.
Although the Air Quality regulations in Spain and Europe do not establish an information threshold for this pollutant, the Ministry of Environment, Housing, and Territorial Planning recommends taking measures to minimize the impact of these particles:
- If the levels are not very high (up to regular): for the general population, although the predicted air quality during these hours may not affect them, it may pose a moderate risk to at-risk groups and sensitive individuals. Therefore, enjoy outdoor activities as usual. However, monitor for symptoms such as cough, throat irritation, shortness of breath, excessive fatigue, or palpitations.
- If the levels are higher (>regular), individuals in at-risk groups and sensitive individuals, such as those with cardiovascular or respiratory diseases or severe allergies, should consider reducing prolonged and vigorous outdoor activities. People with asthma or respiratory diseases should carefully follow their medication plan. Those with heart problems may experience palpitations, difficulty breathing, or unusual fatigue.
- Since the magnitude of the intrusion will vary depending on the time of day and in the coming days, it is recommended that anyone planning outdoor activities check the air quality in their area by accessing the websites listed below.
Furthermore, it is also recommended to avoid actions such as outdoor burning of plant residues and any activity that could emit particles in order to minimize the effects of this episode.
The Ministry of Environment, Housing, and Territorial Planning will monitor this episode, and real-time air quality data for the Community can be accessed at:
- Ministry of Environment, Housing, and Territorial Planning
- Ministry for the Ecological Transition and the Demographic Challenge
- European Environment Agency
- “ICA Air Quality Index” app available on the APP Store
For the interpretation of real-time data and in accordance with Order TEC/351/2019, of March 18, approving the National Air Quality Index, the reference values, such as daily averages, would be as follows (ANNEX I).