The pollution-modified plant odours can confuse bees and, as a result, bees' foraging time increases and pollination efficiency decreases, the study said.

This happens because the chemical interactions decrease both the scent molecules' life spans and the distances they travel.

While foraging for food, insects detect floral scent molecules in the air. Wind currents can carry these molecules up to thousands of feet from their original source to where bees have their hives.

"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 Fuentes, Professor at Pennsylvania State University in the US.

Plant-emitted hydrocarbons break down through chemical interactions with certain air pollutants such as ozone.

This breakdown process results in the creation of more air pollutants, including hydroxyl and nitrate radicals, which further increase the breakdown rate of plant odours.

The researchers sought to understand how these chemical interactions, which start with the presence of air pollutants, would impact bees' ability to find food.

The researchers ran 90,000 simulations representing various bees' foraging and movement patterns amid differing scent levels modified by air pollution and diluted by wind speeds.

The team reported in the journal Atmospheric Environment that, as air pollution increases, hydrocarbons' lifetime and travel distance decreases.

The changes in air chemistry impacted the number of bees able to detect food sources in a given time frame.

"We found that when we confused the bees' environment by modifying the gases present in the atmosphere, they spent more time foraging and would bring back less food, which would affect their colonies," Fuentes said.