The danger of hidden thieves

During heat waves (Khamsin in our language), when the level of ozone production increases - the absorption of ozone on the Earth's surface decreases, which creates more pollution in the air. This phenomenon caused the loss of the lives of about 460 people in Great Britain during the hot summer of 2006.

During heat waves (Khamsin in our language), when the level of ozone production increases - the absorption of ozone on the Earth's surface decreases, which creates more pollution in the air. This phenomenon caused the loss of the lives of about 460 people in Great Britain during the hot summer of 2006.

Plants on Earth play a vital role in reducing air pollution, but new research conducted at the University of York reveals that they may not be able to protect us when we need it most: during peak conditions when ozone production from vehicle emissions, industrial processes and other sources is highest.

The reason for this, as Dr. Lisa Emberson explains, is that during heat waves, when the soil is particularly dry, the plants themselves enter a state of stress and seal the water holes on the tops of their leaves in order to preserve the water stored inside them. This natural defense mechanism makes the plants more resistant to conditions of heavy heat and high ozone levels, but, at the same time, prevents them from absorbing the ozone itself and other pollutants.

"Plants are able to absorb up to 20 percent of the atmospheric ozone created worldwide, so their effect on air quality is significant," explains Dr. Emberson, a senior lecturer in York University's Department of the Environment. "What we tried to do in this study is to quantify this effect in terms of increased ozone levels and the price that humans pay for it."

The research group focused on the summer of 2006, when heat waves and droughts hit Britain and many other European countries. The researchers combined two models that were used to test human health and assess risks to ecosystems in order to compare two scenarios, one when the absorption of ozone by the vegetation is perfect, and the second when the absorption is the least. The difference between these two scenarios was equivalent to 16 days when ozone levels were above the safety threshold for human health across the whole of Britain, and equivalent to 20 such days across the east-central part and eastern Britain. Using these scenarios, the researchers estimated that 970 premature deaths could be caused due to these ozone levels where ozone absorption by the vegetation is the least during the June-July period; According to the researchers, 460 deaths could have been prevented if the plants had absorbed the ozone to their full capacity. All of these estimated premature deaths are in addition to the normal effects of the heat wave itself on human health and mortality.

"The people most sensitive to ozone pollution are those with respiratory and heart diseases," explains the lead researcher. "For example, ozone found at the lowest altitudes can lead to pneumonia, lower lung functions and increased frequency of shortness of breath (asthma). This is why in the garden during periods of high ozone concentration, especially in urban areas, it is recommended for people in risk groups not to perform physical activity." The findings of the new study were published in the scientific journal Atmospheric Chemistry and Physics.

The timing of the publication of the findings of this study comes with another heat wave currently affecting Britain, and Dr. Emberson says that it is likely that the absorption of ozone by the plants will again be reduced. At the same time, the severity of the phenomenon will depend on the degree of dryness of the soil, since the combination of these two factors, namely - the degree of heat and the severity of the drought, is the one that affects the plants to the greatest extent. The researcher claims that the study emphasizes the importance of understanding the future prevalence of these heat and dryness phenomena as well as how the extent of ozone absorption by plants is affected by dryness, extreme heat and interactions with other pollutants.

"The more we know, the better we can determine the degree of success of our efforts to reduce emissions so far, and whether we need additional efforts - in Britain itself, throughout Europe and beyond, since we know that pollutants such as ozone and its precursors are carried by the wind Everywhere," explains the lead researcher.

In addition, the main researcher claims, the research will be able to help the medical and public health authorities. For example, people can make the mistake of thinking that as long as they are outside the city they will not be exposed to poor air quality, so it is important to increase their awareness of this matter. Greater efforts can also be invested in reducing road traffic congestion and ozone emission levels from industrial sources every day, but especially during heat waves.

The news about the study