Molds are part of the fungus family. They form spores to reproduce. Mold spores are released into the air and cause allergies. People with allergies to mold spores sneeze often, and suffer from itchy, runny, stuffy noses. People with asthma may develop flare-ups from spores.
Pollen is made up of tiny particles from trees, grasses, and weeds.
Plants release billions of these particles into the air in order to fertilize other plants. It is common for people with asthma to also have hay fever. Cockroaches are one of the worst allergens. Most people who are allergic to cockroaches do not know it. Dust in the home may contain dead cockroaches and cockroach waste.