Summer starts in a couple of days. It is good when there is an opportunity for a summer time to leave somewhere far away from the asphalt of the cities melting from heat-to the sea, for example, or to the dacha. Unfortunately, for many, this luxury is not available: at least five days a week, citizens are forced to spend their time in the “stone jungle”. Residents of cities tend at the first opportunity, if you can not get into the forest, then at least often visit the city parks and squares.
We used to believe that green spaces in cities have a beneficial effect on human life in the difficult environmental conditions of cities. Plants help to purify the air, emit useful phytoncides.
But not everything is so rosy. Plants in cities, of course, have a lot of benefits. But, as it turned out, there is quite a significant harm. This damage was able to assess an international group of environmental scientists from the German Humboldt University. The results of their research and a group of scientists said.
City plants is guilty of 225 thousand deaths annually
It turned out that urban plants contribute to an increase in ground-level (tropospheric) ozone. This gas, according to the classification of harmful substances, belongs to the substances of the highest hazard class, representing a serious risk for a person – up to a possible lethal outcome.
All plants contribute to an increase in the amount of ozone. However, this is especially different representatives of the routine, dogwood and Aster. And if oranges and lemons (Rutaceae family) is not too frequent guests in our streets, Cornus (dogwood family), burdock and dandelions (Asteraceae) have spread considerably.
On beneficial and harmful ozone
Scientists distinguish two types of ozone. More precisely, ozone is the same: it is a gaseous substance consisting of three oxygen atoms. Ozone, which forms a stratospheric layer protecting life on our planet from solar radiation, is useful. Moreover, without it it would be impossible to exist and the very origin of life on Earth.
We have all heard about ozone holes-the thinning of the ozone layer as a result of the release into the atmosphere of chlorofluorocarbons, methyl bromide, carbon tetrachloride, hydrochlorofluorocarbons and others.
But triatomic oxygen compound toxicity is superior to combat toxic substances, such as chlorine. Therefore, the ozone that is in the lower atmosphere – in the troposphere-is deadly. In addition, the world health organization classifies ozone as a threshold substance. That is, any concentration of this substance is dangerous to human health.
What is the “fault” of plants, or how the formation of “harmful” ozone
In General, the plants are not to blame. The blame for the appearance of tropospheric ozone, however, as well as the destruction of the stratospheric layer, lies with the man, his destructive influence on the ecology of the planet.
Ozone formation is a photochemical reaction normal for our planet. Reaction between nitrogen oxides and volatile organic compounds under the influence of ultraviolet radiation. This is how, with the help of plants, millions of years ago and formed this protective screen of our planet – the ozone layer.
Plants emit organic compounds-monoterpenes and sesquiterpenes, isoprene, etc. Thanks to them, the smell of pine needles, marsh rosemary, orange. The hotter the sun shines, the more volatile organic compounds are released by plants, and as a result – the formation of ozone, which then rises to the upper atmosphere.
But the trouble is that these volatile organic compounds react with nitrogen oxides, which are contained in the exhaust gases of cars. As a result, in addition to the danger from the exhaust gases themselves (nitrogen oxides are ten times more toxic than carbon monoxide), ozone is formed.
According to scientists, the presence of plants increases by almost 60% the amount of ozone in cities. Given the number of cars in Metropolitan areas, such a volume of ozone does not have time to retire to the stratosphere.
The dangerous ozone
Being a chemically active compound – oxidant, ozone, getting into the body, causes oxidative stress. As a result, there is an avalanche formation of free radicals that negatively affect living organisms, causing their degradation.
Ozone primarily affects the respiratory tract, causing cough, pneumonia, exacerbation of attacks in asthmatics, emphysema and pulmonary edema. In people who are not prone to respiratory diseases, ozone causes increased fatigue, nausea, headache. And they also risk getting asthma, bronchitis and other problems.
Ozone contributes to the exacerbation or occurrence of allergies. And most importantly – ozone genotoxic. That means it’s a mutagen or a carcinogen. That is, ozone is a substance that causes gene mutations or tumors.
The most dangerous effects of ozone are on children, the elderly, people with cardiovascular diseases and, as mentioned above, those with respiratory problems.
Well, as a “bonus”: ozone destroys not only living organisms, but also building materials and structures.
How to protect yourself from ozone
Unfortunately, our life is arranged in such a way that most people are forced to live in cities. It is difficult to go against natural laws, and the process of ozone formation cannot be stopped. You can only reduce the amount by reducing the amount of exhaust gases. However, it is for the most part also outside the power of the layman.
The only thing you can do for your health and the health of your loved ones – to be as little as possible in the open sun, and the more not to engage in active physical activity in the heat: the hotter the sun shines, the more actively the process of ozone formation. The maximum falls on midday hours, at least-in the early morning.
The warning about avoiding the hot sun applies not only to citizens, but also to summer residents: ozone is carried at a distance of more than 100 kilometers from cities.