The Resurrection of the “Miasma Theory”

The fight against a 108-year-old pathogen.

(Image Credit: Dmitry Ryzhkov)


Since the emergence of the car in 1908, automobile emissions have been destroying the American environment and body alike. In the 17th century, epidemiologists coined the term miasma. Miasma is defined as an oppressive or unpleasant atmosphere that surrounds or emanates from a source. Under the theory, experts speculated that disease was transmitted through poisonous vapor saturated with particles from decomposed matter. Diseases such as cholera and the bubonic plague were thought to stem from “bad air”.  In the 1800s the “miasma theory” was replaced by the “germ theory”, which suggested disease was caused by pathogens, not pollutants. Fortunately, the creation and diligent study of the 17th century “miasma theory” was not wasted. The “miasma theory” aligns perfectly to 21st century automobile pollution. In the United States, automobiles account for 15% of national greenhouse gas emissions. The short list of harmful pollutants released by vehicles includes: mono-nitrogen oxides, particulate matter, hydrocarbons, carbon monoxide, sulfur dioxide, and various greenhouse gases. Each pollutant poses a different threat to human health. Although 17th century epidemiologists wrongly applied the “miasma theory” to disease transmission, 21st century environmentalists should resurrect the theory to understand American automobile pollution.

21st century Americans are experiencing two different types of automobile pollution, external and internal. As the “miasma theory” suggests, disease and discomfort arise in response to pollution. Automobile emissions are an overlooked disease. Our body is an environment, and its health is being challenged by a 108 year old pathogen. Automobiles first pollute the external environment, however, what is an external issue quickly becomes an internal catastrophe. Airborne automobile pollution does not discriminate. Once inhaled, the pathogen is capable of causing widespread human internal environmental damage. The health of our internal environment is directly related to the health of our external environment. In an automobile crazed America, where one half of citizens live in areas that do not meet federal air quality standards, the health of the internal human environment is being contested.

Vehicle emissions are difficult to quantify. The “miasma theory” assists in framing the convoluted and multi-dimensional problem of vehicle emissions. Human malignancies are generally explained by differences in environment (Vandenbroucke 1988). Perhaps this once defunct theory of disease transmission has more relevance today than it ever has. In the 17th century, the “miasma theory” falsely suggested diseases were created in the presence of “bad air”. However, in an automobile crazed 21st century America, “bad air” has proven to cause disease. Asthma and Cancer rates for urban residents are on the rise. Human exposure to automobiles, including the associated airborne fine particles and carcinogenic constituents, are tied to increased cancer levels (Lewtas 2007). Humans often have narrow scopes when attempting to quantify problems. Even the most intelligent person has trouble connecting the dots at times. No longer should the external environment be separate from the internal human environment, internal health is dependent on external health. The previously defunct “miasma theory” assists in understanding the disease that is 21st century American automobile emissions.



  1. Vandenbroucke, “Is The Causes of Cancer’ a Miasma Theory for the End of the Twentieth Century?” International Journal of Epidemiology: Vol 17 No 4. 1988.
  2. Joellel Lewtas, “Air pollution combustion emissions: Characterization of causative agents and mechanisms associated with cancer, reproductive, and cardiovascular effects” Reviews in Mutation Research: Volume 636, Issues 1–3. 2007.
  3. The Union of Concerned Scientists, “Car Emissions & Global Warming: Transportation is one of the largest sources of US global warming emissions—but cleaner vehicles can help”. 2015.

Image: Dmitry Ryzhkov


Student Author: Aleks Taylor (The University of Vermont)

Faculty Advisor: Rob Williams, UVM Professor of Communications. (The University of Vermont)


Bio: My name is Aleks Taylor, I am a political science – environmental studies double major at the University of Vermont.



I am a political science - environmental studies double major at the University of Vermont.
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