August 1, 2008 Biochemists have shown that air pollution inhibits the distance that flower's fragrances can travel. Scent molecules usually travel easily in the air, but pollutants break them apart, which destroys the smell. The researchers found that these delicate odors responsible for attracting bees and other pollinating insects are traveling as little as one-third of their former distances.
Soon, it may be harder to stop and smell the roses. Something is killing off flower's sweet smell. Now, we can discover what the culprit is.
Ah, the sweet smell of flowers can be hard to resist. When you go and visit a garden the first temptation you have is to smell a flower, explains Jose Fuentes, Ph.D., atmospheric scientist University of Virginia in Charlottesville, Va.
But hurry up and catch a whiff while you still can.
Atmospheric and environmental scientists report that flower's scents are being destroyed. What's to blame for the disappearing aromas? Pollution. Fumes from cars and factories are pumping pollutants into the air, which may be destroying flower's fragrances.
"What we find is that these fragrances only travel one-third of the distance that they used to travel," Dr. Fuentes says.
Flowers produce scent molecules that travel easily in the air. Pollutants break apart the fragrance molecules, destroying their smell. Our noses will miss the pleasant fragrance, but bee's depend on it.
"The pollinators are spending more time trying to locate food and less time trying to actually harvest food that they need," Dr. Fuentes notes.
Wiping out flower scents could have a major impact on bee populations. But we can help bring back the bees and flower smells.
Dr. Fuentes explains, "One specific action that we can take is to really work towards having a very clean environment."
Flower populations may also diminish because plants need bee's to pollinate that allows flowers to reproduce. Now, we can make a clean effort for a chance to smell the flowers.
HOW WE SMELL: A smell is the sensory response to the complex mixtures of chemicals in the air around us, called odorants. We are able to sense these chemicals because they bind to protein receptors that line the cells in our nose. Each kind of receptor can only detect specific chemical compositions, producing the sensation of different smells. These receptor proteins are produced from about 1,000 different genes: almost 3 percent of our total gene count.
THE NOSE KNOWS: Our sense of taste is partially enhanced by smell, which is why food may taste bland when we have a cold that blocks the nasal passages. Nerve receptor cells within the nose detect odors carried into the organ by air, and transmit signals to the brain through the olfactory nerve.
ABOUT AIR POLLUTION: Air pollution is made up of many kinds of gases, droplets and particles that can remain suspended in the air. This makes the air dirty. The easiest way to visualize airborne particles (also called aerosols) is to exhale outside on a cold day and watch the fog come out of your mouth when water vapor forms water droplets. The same thing happens in the atmosphere, but for different reasons. Under certain conditions individual molecules come together and form particles -- a chemical soup. In the city, air pollution may be caused by cars, buses and airplanes, as well as industry and construction. Ground-level ozone is created when engine and fuel gases already released into the air interact when sunlight hits them. Ozone levels increase in cities when the air is still, the sun is bright and the temperature is warm.
The American Geophysical Union and the American Meteorological Society contributed to the information contained in the TV portion of this report with support from the Camille and Henry Dreyfus Foundation, Inc.