Unlike spring allergies which are usually caused by tree pollen, summer allergies are usually caused by grass pollen. Almost any type of grass can cause allergic symptoms, including Bermuda, fescue, Kentucky bluegrass, and more.
Summer allergies can also be worsened by smog and poor air quality. While smog is not an allergen by itself, poor air quality can cause irritation and worsen your other allergy symptoms. This summer has been particularly bad for smog and air quality in Central Ohio, thanks to an active Canadian wildfire season that has spread smoke over much of the United States.
Indoors, the summer can also be a time when mold grows throughout homes due to an increase in warm, damp air, causing symptoms in those with mold allergies. Dust mite populations also tend to peak in the summer, which can cause allergic reactions in some people.