Amid the smog, butterflies, bees and other insects are having a hard time smelling the flowers they so dutifully pollinate. Researchers found that common, ground-level air pollutants such as nitrogen oxides (found in diesel exhaust fumes) and ozone react with floral scents, leading to reduced pollination, according to a newly published study in the journal Environmental Pollution. “We knew from our previous lab studies that diesel exhaust can have negative effects on insect pollinators, but the impacts we found in the field were much more dramatic than we had expected,” said Robbie Girling, pr…