Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen

► O3 reduces the viability of ragweed pollen. ► ROS and allergens of ragweed pollen were not affected by O3 exposure. ► O3 enhances the activity of the ROS-generating enzyme NAD(P)H oxidase. ► O3 increases ragweed pollen allergenicity through NAD(P)H-oxidase stimulation.