Homeostasis is the process by which the body maintains normal conditions for things like temperature, heart rate and growth rate. Environmental pollution can dramatically affect homeostasis because chemical pollutants can behave like hormones, which are the molecules that organs use to "talk" to each other.

Disruption of homeostasis can occur in many ways. These include direct damage to the organs involved in maintaining homeostasis, mimicry of hormones that control homeostasis and deficiencies in vitamins that are needed to maintain healthy organs. Disruption of homeostasis by environmental pollution can result in cancer, neurological diseases and breathing problems.

Endocrine disrupting chemicals (EDCs) are chemicals that behave like hormones. Hormones regulate things like growth, hunger, weight, water balance and reproductive organs. Thus, EDCs can dramatically affect a person’s health.

Common EDCs are plastics such as BPA (bisphenol A), which leach from plastic food and drink containers. EDCs can start their bad effects in the womb, before a person is born. EDCs have been linked to obesity, altered mental behavior, cancer and infertility.

Air pollution is inhaled into the lungs, which can damage the lungs. However, particles in the air can go from the lungs to other organs in the body, causing damage elsewhere. Air pollution contains nano-sized particles that can enter the bloodstream from the lungs and travel to nerves throughout the body. They can also end up in the brain.

These particles cause damage wherever they go, resulting in inflammation at that location. Inflammation is the activation of the immune system, as if the body is fighting off an infection by a virus or bacteria. A study from Turkish researchers, published in the "Journal of Toxicology," reports that air pollution has been linked to neurological disorders, including stroke, Alzheimer’s disease and Parkinson’s disease.

Vitamin A is essential for normal vision and healthy organs. Vitamin A is part of the protein in the eyes that absorbs light. It also is important for a healthy immune system.

Air pollution containing molecules called polyhalogenated aromatic hydrocarbons (PHAH) have been shown to cause vitamin deficiency. These chemicals get into the body and increase the breakdown of Vitamin A. It is believed that they block the functions of enzymes that make Vitamin A.

Air pollution can contain particles that react with metal ions that are naturally found in the body. For example, iron atoms help carry oxygen in the blood and are one of the trace elements needed for healthy bodies. The particles in air pollution have chemical arms that react with iron to form harmful products. These particles get stuck in the lungs, react with iron, and can result in an accumulation of iron in the lungs.

The harmful products that are made when air pollution reacts with iron atoms starts damaging the lungs, causing the immune system to react as if there is infection. Mucus begins to build up and breathing problems occur.

Homeostasis can apply to other things besides the body. Environments and ecosystems also maintain a certain homeostasis by having steady climate, weather, temperatures, organism populations and nutrient cycles like the water and nutrient cycle.

Like human homeostasis, ecosystem homeostasis is affected by pollution and new and toxic chemicals entering the environment. This can affect important factors like pH levels, salinity, temperature and climate that will affect an ecosystem's homeostasis.

For example, changes to temperature of ocean waters have lead to massive death of algae and other microscopic aquatic organisms, which has, in turn, lead to coral reef bleaching. This affected the homeostasis of the environment and has drastically affected the entire coral reef ecosystem.