Allergens are anything that triggers an allergic reaction in an individual.  A typical indoor environment is full of pollutants that can be characterized as allergens, and they take away from the well-being of an occupant.

Some Allergens:

Pollen, dust mites, dust mite fecal matter, pet dander, mould spores, fungal spores, and cockroach fecal matter.

Harmful Effects:

Allergens typically cause “allergic reactions” with a degree of severity that varies from one individual to another and can be minor ailments such as nasal congestion, red eyes, sneezing, wheezing, rash or life-threatening such breathlessness, acute vomiting, diarrhea, major inflammation of skin and internal organs, and cardio-vascular failure.