Air pollution reduces flower fragrance

A new study from the University of Virginia says air pollution from power plants and cars is damaging the scent of flowers and thus limiting the ability to follow the scent of the Pollinated insects. This partly explains why wild populations of some pollinators, particularly bees need nectar for food, are declining in some parts of the world, including California. and the Netherlands.

Jose D. Fuentes - Professor of Environmental Science at the University of Virginia and co-author of the study - said 'Fragrance molecules emanating from flowers are in less polluted environments, such as in in the 1980s, it was possible to move between 1,000 and 1,200 meters; but in the polluted environment in the direction of the wind blowing in the big cities today, they can only bring the fragrance from 200 to 300 meters. This will make it more difficult for flower-pollinating pollinators. '

The potential result is a vicious circle where pollinators struggle to find enough food to maintain their quantity, and because of that the flowering plants will not be pollinated enough to multiply and Diversified development.

The professor of Virginia Jose Fuentes University (in the middle) and the students of Quinn McFrederick (left) and James Kathilankal (right) are the authors of this study. (Photo: Dan Addison)

Other studies and practical experiences of farmers show that in recent years the number of bees, especially bumblebees and butterflies has been significantly reduced. Fuentes and his University of Virginia research team, including Quinn McFrederick and James Kathilankal, argue that air pollution - especially during the hottest part of the summer - could be a cause. .

In order to investigate this factor, they created a mathematical model to calculate how the fragrance of flowers spread in the wind. The aroma molecules emitted from the flower are volatile and quickly adhere to contaminants such as ozone, hydroxyl and nitrate radicals, which will lose the scent emitted. This means that instead of spreading with the pristine scent at long distances in the wind, the scent has changed its nature and in some respects the flower is no longer fragrant. This forces pollinators to look far and longer and may have to rely on more eyesight and rely on less scent.

Scientists have calculated the level of scent and distance that scent can fly under different conditions, from the levels of relatively unpolluted industrial money changes, to the current conditions. in some rural areas wind direction from big cities.

Fuentes said 'It is clear that air pollution reduces the scent of flowers by about 90% in previous periods of heavy industries and automobiles. And the more pollutants in an area, the greater the risk of scent of flowers will be reduced. '

The study is published online in the Atmospheric Environment.

The study was funded by the US National Science Foundation.