Many common substances can be allergens. Pollens, food, mold, dust, feathers, animal dander, chemicals, and environmental pollutants cause people to suffer allergic reactions.
Pollen arises from trees, grass, and weeds – it floats in the air during the spring, summer, and fall seasons. As these pollens travel in the air people encounter them in their noses, eyes, ears, and mouths. Small particles of pollen are easily carried through long distances by wind and tend to cause allergies.
Mold is a fungus, typically found in damp dark places. These microscopic spores also fly in the air and trigger allergy symptoms. Mold colonies reproduce and release spores year-round, they become dormant when temperatures drop below freezing but do not die.