the stormy celiawhich entered this past Sunday from the southwest and will remain on the Peninsula on its way to the east, has left a exceptional presence of dust from the Sahara in suspension in almost the entire peninsula, although the phenomenon has been more noticeable in several areas of Levante.
The one known as calima, which has not occurred with this intensity for several decades, has given these areas an extraterrestrial aspect and has left impressive images. This morning, in fact, millions of cars have woken up full of mud in areas where this suspended dust has mixed with rainwater.
But the worst of this phenomenon is yet to come. According to Meteored’s prediction, the highest concentration of dust in suspension over large areas of the Peninsula will occur this Tuesday afternoon.
Normally from 40 µg/m³ It is considered that the amount of dust in suspension begins to negatively condition the quality of the air and, therefore, it is harmful to health. The main symptoms are linked to respiratory problems and irritation of the mucous membranes: cough, nasal obstruction and itchy eyes. If the phenomenon is persistent, bronchospasm, chest pain and asthma can occur, especially in people with allergies or pathologies.
This afternoon, the concentrations of dust in suspension could even exceed 300 µg/m³ in the most affected areas, so it is recommended to avoid prolonged outdoor activities that are not necessary.
The cloud will spread throughout the peninsular territory and the calima is not expected to leave the peninsular territory until this Thursday, when the wind will have a more marked northerly component.
What is haze?
Haze is the suspension in the atmosphere of non-aqueous solid particles extremely small, invisible to the human eye, but numerous enough to give the sky an opalescent appearance, according to the State Meteorological Agency (Aemet).
The size range of these particles ranges from units below microns to tens of microns and the origin is very varied: can come from soil, forest fire smokeindustrial emissions, salt spray, volcanic eruptions and even be composed of organic matter, such as bacteria, pollens, animal hair… When the origin is mainly a dust or sand storm, we speak of “dust haze”. ” or “suspended dust”.
The term haze is used when low visibility and high visibility coincide. relative humidity less than 70%. The degree of humidity is what differentiates it from mist, which is mainly made up of water droplets. In the Canary Islands and the Peninsula, episodes of haze are usually due to intrusions of Saharan dust, as is the case.
Two types of haze
Depending on the origin of the particles, there are two kinds of haze, as explained by eltiempo.es. Type A is known as ‘natural’ and is formed from the transport of sand, water salts (sodium) or other elements present in the environment. The B are the so-called special events, whose origin lies in pollution or forest fires and whose breathing is especially dangerous to health.
What happened this past Monday on the Mediterranean coast is a clear example of type A, which also occurs frequently in the Canary Islands when the easterly component winds They drag dust from the Sahara desert to the archipelago. An example of class B is the one that occurs in winter and with conditions of great atmospheric stability in large cities, such as Madrid. In this second case, the lack of wind and precipitation and thermal inversion favor a stagnation of pollutants over cities and reduce visibility and air quality.
This is how the calima affects more communities in Spain:
Precipitation and air quality
When there is type A haze and precipitation occurs, a phenomenon known as ‘rain of mud’ or ‘rain of blood’, when water droplets drag suspended dust particles and deposit them on the ground and objects. Something that could happen this Tuesday due to the rain forecast. If it is type B, it can lead to ‘acid rain’, which is harmful to the environment.
Regarding its effect on air quality, haze tends to make it worse, especially the PM10 index -particles dispersed in the atmosphere with a diameter of less than 10 µm-, details eltiempo.es. In Spain, in some episodes it has reached exceed 40 times the maximum recommended value.
The haze can also have negative consequences on health. The main symptoms are linked to respiratory problems and irritation of the mucous membranes: cough, nasal obstruction and itchy eyes. If the phenomenon is persistent, bronchospasm, chest pain and asthma can occur, especially in people with allergies or pathologies.