Which allergens present in homes and offices cause most frequent allergic reaction among sensitive people?

Many allergens present in an indoor environment such as the homes or offices can contribute to allergic reactions in sensitive people. These include the following:

1) dust mite droppings
2) mold
3) animal dander
4) cockroach debris
5) tobacco smoke and smoke from wood–burning stoves
6) household chemicals

Beside, all these can also aggravate respiratory problems when encountered indoors. Most indoor allergens are small particles that can easily become airborne and inhaled. People suffering from asthma could have a tough time because many types of indoor allergens can irritate their airways and cause an asthma attack.