Air pollution is so grave that bees are also feeling its negative impact on our planet.

The tiny insects, which rely on their sense of smell to survive, are suffering from "pollution confusion," which result in the rapid decline in their population. As pollinators, their massive drop in numbers may also result in the shortage in crop yield in the long run.

Plants usually release a scent that bees use to track and locate their food. Because of the scent's volatile nature, it instantly mixes with pollutants in the ozone, including hydroxyl and nitrate radicals, and results in a chemical reaction.

To find out how and up to what extent the chemical reaction affect bees' ability to find food, researchers led by Pennsylvania State University conducted a study.

Long travels for tiny bees

The researchers ran 90,000 simulations to represent the bees' movements amid altering scent levels modified by concentration of air pollutants and wind patterns.

The experiment revealed that as air pollution increases, the lifetime and travel distance of the odor molecules emitted by the plant it pollinates decreases. The chemical change messes with the bee's efficiency to successfully locate the plumes of floral scents they need to find their food.

"Many insects have nests that are up to 3,000 feet away from their food source, which means that scents need to travel long distances before insects can detect them," said Jose D. Fuentes, professor of meteorology and atmospheric science at Penn State in a press release.

"Each insect has a detection threshold for certain kinds of scents and they find food by moving from areas of low concentrations of scents to areas of high concentrations," he added.

In addition, the study revealed that as the odor molecules are broken down to pieces, the bees' foraging time also increases. This results in having less food to bring back to their colonies. Less food for these species means population decline.

"It's similar to being asked to get a cup of coffee at the nearest cafeteria while you are blindfolded. It will be hard to locate the coffee shop without using visual cues. The same could happen to insect pollinators while foraging for food in polluted air masses," Fuentes said.

The study, which was published in the journal Atmospheric Environment, comes after research suggest that bee populations are in severe decline due to rapid urbaziation which causes them to lose their natural habitat.

The U.S. Department of Agriculture and the National Institute of Food and Agriculture's Bee Informed Partnership notes that more than 28.1 percent of America's bee colonies were lost during the 2015-2016 winter season.