Dust storms that hit Israel during transitional seasons can cause significant health damage. A new study shows that one of the most effective ways to combat them is through forests, which know how to curb the dust and even use it as a fertilizer
By Naa Rubin, Angle, Science and Environment News Agency

In the last few weeks we woke up many times to mornings characterized by moderate to heavy haze. The haze accompanies the transition seasons and is caused by dust storms that arrive during this period. The phenomenon of desertification, a process in which many areas become more and more arid and the amount of biological activity in them decreases, causes the frequency of dust storms to increase. Various models predict the future location of the storms, their frequency and intensity, and the forecasts show that the general trend is an increase in the number of storms. Because of this, a broad attempt has been made to understand the positive and negative consequences of the dust storms.
"Dust storms form mainly in arid or semi-arid areas, where the vegetation cover is sparse, so strong enough winds are able to pick up the small soil particles and carry them for relatively long distances," says Dr. Avner Gross, a researcher at Ben Gurion University. Due to their frequency, intensity and large area that they can affect, dust storms have a huge impact on the climate and are responsible for many environmental phenomena, including Reducing precipitation, interfering with the proper functioning of satellite communications and significant air pollution.
The dust, which is transported as a substance with tiny particles, also reaches urban and rural environments inhabited by humans. In addition to the effect on the climate, the dust can also cause health problems in humans. The particulate matter measured during the storms sometimes far exceeds the maximum concentration of particulate matter recommended by various health organizations. In Israel, for example, which is located in a semi-desert area exposed to dust storms from both the east and the west, the concentration of particulate matter during storms can reach up to 2,000 microns per cubic meter of air and even more (when the maximum amount according to the World Health Organization should be less than 50 microns per cubic meter air). Among the health consequences of the dust are heart diseases, lung diseases, breathing problems, allergies and more.
Various studies have shown that vegetation may be a natural barrier to dust storms, thanks to the absorption of a large amount of the particulate matter that makes up the storm on the leaves. Photo: abhay singh – unsplash
Reduces 28 percent of atmospheric dust
How can the damage dimensions of the dust storms be reduced? Various studies have shown that vegetation may be a natural barrier to dust storms, thanks to the absorption of a large amount of the particulate matter that makes up the storm on the leaves. The storm surge comes in strong force, and when it finds its way through a forested environment, its concentration in the urban environment is reduced. This effect of the forest also exists here. Israel is located in a semi-desert area, characterized by large amounts of dust. When the forest is in the path of the storm, a large amount of dust particles accumulates on the vegetation, and the amount that reaches the urban area decreases.
Thus, for example, in the Lahav forest, which is located a little north of Beer Sheva, a study was carried out that showed that the pine trees on which a huge amount of dust accumulates, help to reduce the particulate matter in the surrounding settlements. "The pine trees were chosen because they were planted in large numbers in Israel in general, and in the northern Negev in particular, an area that dust storms frequent every year. The presence of these trees in a location exposed to dust creates an ideal research area for the interaction between dust and forests," says Dafna Oni, who carried out this study In the laboratory of Prof. Yitzhak Katara at Ben Gurion University. "It was found that pine trees are effective in absorbing dust compared to other trees because of their height and because the pine needles increase the surface area of the tree." The height of the tree, the shape of the leaves and its surface area, result in the refraction of the wind, and allow the enormous accumulation of dust particles on it. "During moderate storms (about 600 micrograms of dust per cubic meter), we found that at the edge of the forest the concentration of atmospheric dust decreased by 28 percent compared to an area without a forest," she adds.
Is the dust beneficial to the plant system?
When the storm and particulate matter are blocked by the forest, the amount of dust that accumulates on it is enormous. In fact, a completely new mass of matter is created, which comes from a distance and contains different chemical properties than the vegetation in the forest. This mass is added to the plant system and becomes part of it.
"Trees that are in the flow path of the dust storm interact with the particles that reach them. During the dust storms, the forest both improves the air quality in the nearby settlements and 'fertilizes' itself with nutrients," Oni says. "It's a win-win situation, where everyone benefits."
That is, in addition to the negative effects of the dust storms, they may also have a positive effect on the plant system. How It Works? The dust particles contain a high concentration of phosphate (a fertilizer that contains phosphorus and is essential for plants), the lack of which harms the normal functioning of the ecosystem and is a limiting factor for its growth. Through the dust, the phosphate can reach from far away to ecosystems where it is lacking, and enter the biochemical cycle of the system. When it is inside the plant system, it can help fertilize it.
"Phosphorus is an essential element for every living thing because it is the building block of important molecules in the living body. The main source of phosphorus is in the earth's crust, so it reaches plants mainly through the soil," says Gross. The causes of phosphorus deficiency are different in the different regions, but appear in many terrestrial systems. At the time of their original formation, many of the soils contained a sufficient amount of phosphorus, but in many of them it has decreased over time. In the tropical regions of South America, for example, the huge amounts of precipitation cause the phosphorus to be washed from the soil and removed from the system. In other areas, although the phosphorus appears in the soil, the plant system does not have the possibility to use it, and therefore it is not available to it. This is what is happening in Israel. "Low availability of phosphorus also exists in the Mediterranean region, especially in environments where there are calcareous soils with a high calcium content, this is because the calcium is able to bind the phosphorus in the soil relatively strongly and prevent its availability to plants."
Most of the world's dust is produced in the Sahara desert, from where it is transported long distances and can even reach the tropical forests of America. Photo: Willian Justen de Vasconcellos – Unsplash
In other parts of the world, on the other hand, the amount of phosphorus available in the soils is enormous. "The supply of phosphorus from external sources such as dust can help the primary production (turning inorganic material into organic material in the process of photosynthesis) of the ecosystem. Most of the dust in the world is produced in the Sahara desert. The dust from the Sahara can be transported long distances and even reach the tropical forests of America." Gross number.
"In research in our laboratory, we are testing the hypothesis that trees that evolved evolutionarily in phosphorus-poor systems that receive large amounts of dust, such as the tropical forests in America or forests in Israel or other areas affected by dust, have adapted to themselves the ability to assimilate the phosphorus carried in the dust through the leaves, thus giving themselves an advantage over plants that can take Phosphorus only through the roots," says Gross. Since dust storms often arrive in Israel, it is possible that the natural forests in Israel have adapted to this ability and thus the dust storms actually benefit the forests and provide them with their necessary phosphorus additions, which cannot be absorbed through the roots in the soil.
Possibilities for applying the discoveries in the field
As a result of the changing global climate, dust storms are expected to become more frequent, and their natural fertilization will continue to contribute to ecosystems. It is understood that at that time, the dust will continue to be a significant factor in air pollution, but it is possible that the understanding that the forest absorbs a large part of the dust can help reduce the dust. "It is possible that the results of the study will be used by planners, who can take into account the common wind direction of the dust storms and on days without a dust storm, and thus plan the location of the planting in relation to the settlement. This is because even on days without a dust storm there is a particle