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Allergies Health Center

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Environmental Illness - Toxic Chemicals in Our Environment

Bacteria, molds, viruses, and other biological contaminants

Bacteria and molds can breed in stagnant water that builds up in humidifiers, drain pans, and ducts, or where water collects on carpet, ceiling tiles, and insulation. Humidifier fever is an illness caused by toxins from microorganisms that grow not only in large heating and cooling systems in buildings but also in home systems and humidifiers. Legionella pneumophila is an indoor bacterium that can cause Legionnaires' disease.

Some viruses can survive on household surfaces, such as counters or floors, or they can get spread through the air when an infected person sneezes or coughs. You can help control viruses by:

  • Cleaning household surfaces with a disinfectant.
  • Having adequate ventilation in your house.
  • Having anyone with a viral infection, such as a cold or the flu, cough or sneeze into the bend of the elbow or into a tissue.

Pet dander, pollen, dust mites, molds, and rat and mouse urine are allergens that can cause asthma attacks, allergic rhinitis, and other lung problems. Symptoms of illness caused by biological contaminants include sneezing, watery eyes, shortness of breath, lethargy, dizziness, and digestive problems.

Exposure early in life to indoor allergens such as molds may increase the risk of allergies or asthma.5 Allergies to molds can also make asthma attacks worse or cause other breathing problems.

Keep your home clean and as free from dust as possible to help reduce allergens. There are many ways to control dust and dust mites in your home, such as washing bedding in hot water to kill dust mites and eliminating furnishings, such as drapes, that collect dust. Also, there are many steps you can take to control animal dander and other pet allergens.

Exhaust fans that vent to the outdoors and are installed in kitchens and bathrooms can help get rid of moisture that allows microorganisms, including molds, to grow. When modern building materials get wet, they provide an ideal place for the growth of molds, which can make asthma attacks worse and may cause other respiratory symptoms. Ventilating attic and crawl spaces and keeping humidity levels below 50% can help prevent moisture buildup in building materials. There are other ways to control indoor molds, such as preventing leaks, removing wet materials, storing fireplace wood outside the home, and using a dehumidifier during humid weather.

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