Diesel fumes may be reducing the availability of almost half the most common flower odours that bees use to find their food, new research has found.The new findings suggest that toxic nitrous oxide (NOx) in diesel exhausts could be having an even greater effect on bees’ ability to smell out flowers than was previously thought.NOx is a poisonous pollutant produced by diesel engines which is harmful to humans, and has also previously been shown to confuse bees’ sense of smell, which they rely on to sniff out their food.