Understanding Immunology:
Your body is made up of natural defense systems to protect you against harmful substances. Physical barriers such as the skin, nose hair, and eyelashes prevent contaminants from getting inside your body. Immunological barriers like white blood cells and lymphatic organs recognize foreign invaders and work to neutralize their effects in deferent ways.

When the immune system has been weakened or compromised, your body does not have these means to fight against foreign invaders. Cancer patients undergoing chemotherapy, AIDS/HIV patients, young children and the elderly are particularly at risk.

Understanding Toxicology.
Toxicology is the study of the negative effects of contaminants. Studies are done using animals to see the levels at which chemical cause health effects. The data that is obtained from animal studies then applied to humans, with safety factors added.

Health Effects.
There are ways that you can be exposed to contaminants: inhalation, ingestion or skin contact.

The following table shows some common air pollutants and their potential health effects.

Common Air Pollutants	Symptoms
Radon	Lung Cancer
Volatile Organic Compounds (VOC's)	Irritation; Cancer
Tobacco Smoke	Eye, Nose and Throat Irritation; Lung Cancer
Odors; Bioeffluents	Discomfort
Carbon Monoxide, Carbon	Fatigue, Chest Pain
Carbon Dioxide, Ozone	Impaired Vision and Coordination, Nausea, Headaches, Dizziness, Confusion, Flu-like Symptoms, Weakness, Disorientation
Nitrogen	Eye, Nose and Throat Irritation, Impaired Lung Function and Increased Respiratory Infections
Microbial Allergens	Humidifier Fever; Hypersensitivity Pneumonitis; Eye, Nose and Throat Irritation
Legionella bacteria	Legionnaires Disease; Pontiac Fever; Eye, Nose and Throat Irritation, Wheezing and Coughing, Fatigue, Skin Rash, Severe Allergic Reactions, May Cause Cancer
Formaldehyde & Other Aldehydes	Eye, Nose and Throat Irritation, Wheezing and Coughing, Fatigue, Skin Rash, Severe Allergic Reactions, May Cause Cancer