Environment & Health

Big Picture

There are many environmental factors that can affect human health, including pollution, carcinogens, and bioterrorism. These three, if not properly controlled, will have severe effects on human health. Air pollution can worsen lung diseases or cardiovascular issues, and carcinogens can cause cancer. Bioterrorism, if not caught, can lead to death, as in the case of the anthrax scare in 2001.

Key Terms

Air Quality Index (AQI): Takes into consideration the levels of pollutants in the air and how these pollutants affect human health.

Pollution: When chemicals, heat, and noise are added to the environment beyond its capacity to absorb them.

Cancer: Disease that occurs when the cell cycle is no longer regulated and cells divide out of control.

Carcinogen: Anything that causes cancer, either naturally formed or created by man.

Tumor-Suppressor Gene: Normally works to prevent cells with damaged DNA from dividing.

Tumor: A cluster of cells that can either be benign or malignant.

Bioterrorism: When diseases are intentionally released or spread.

Air Quality & Pollution

If the Air Quality Index(AQI) is high, then people should not go outdoors because the pollutants can have severe effects on their health. Those with asthma, respiratory illnesses, or other lung problems should avoid exposure to polluted air, because it can make these problems worse. There are two main pollutants studied when figuring out the AQI:

  • Ozone: A gas that forms when pollutants are heated by the sun.
  • Particulates: Small particles that are formed as a result of burning fossil fuels.

Smog is a combination of the two pollutants above, and it is unhealthy to go outside when there is visible smog (visible smog means that the AQI is high).

Air Quality Index
Image credit: EPA, Public Domain

While we may think that most pollutants are found outdoors, there are many harmful pollutants in the air inside our homes as well. Examples of indoor pollutants include mold, bacteria, radon, and carbon monoxide. Inhalation of carbon monoxide quickly leads to death.

All forms of pollution, not just air pollution, can have a negative impact on human health. Some of the health effects of pollution are shown to the right.

Effect of pollution on helath
Image credit: Mikael Häggström, Public Domain


Environment & Health cont.


Cancer happens when a genetic mutation in a cell causes it to reproduce uncontrollably. Most carcinogens produce mutations in genes that control the cell cycle. For example, mutations in the tumor-suppressor genes could cause cells with damaged DNA to go unnoticed and reproduce, thus causing some sort of tumor.
Examples of carcinogens:

  • Viruses (example: hepatitis B)
  • Radiation (the most common is UV radiation)
  • Tobacco smoke
  • Chemicals in food

Tumor and cancer are not the same thing:

  • If a tumor is benign, it remains at one part of the body and does not prohibit any of the body’s normal functions.
  • If the tumor is malignant, it can grow uncontrollably and can grow into other tissues.

Sometimes, cells of the malignant tumor can spread to other parts of the body via the bloodstream and then grow in other parts of the body, further weakening the body.


When treating cancer, doctors try to remove the tumor without removing the healthy cells in the body. Surgery, chemotherapy, and radiation are all treatments that attempt to attain this goal.
A patient is more likely to beat the cancer and survive when the cancer is detected early and the tumor is still small and controllable. Knowing the early signs of cancer and getting routine tests help to detect cancer early.


Viruses, bacteria, or toxins produced by bacteria can be spread through the air, food, or water or through contact with the skin. One of the best-known incidents of bioterrorism in the United States happened in 2001 when someone sent anthrax spores through letters, infecting whoever opened those letters.