We already know that air pollution hurts the environment, makes our cities smoggy, smells bad, can damage our lungs, and causes many other ill effects. Recent evidence now shows that it could also increase the incidence of appendicitis.

The appendix is a tube-shaped sac extending 3-6 inches from the ascending colon, situated in the lower right abdomen. It consists of tissue that absorbs toxins (lymphatic) but medical scientists don’t fully understand its functional role within the digestive tract.

For unknown reasons, the appendix can swell with infection and inflammation, which develops into a condition called appendicitis. This happens very quickly and the likely result is rupture of the appendix within 24 hours, spreading infection into the surrounding tissue, potentially leading to a sometimes-fatal condition (peritonitis). To avoid serious complications, it requires immediate medical attention in which a surgeon removes the swollen appendix in a procedure called an appendectomy.


Abdominal pain is the main symptom of appendicitis, and it has some unique characteristics. The onset of abdominal pain is usually sudden, often causing a person to wake up at night. It can begin near the navel and then move lower and to the right. It is generally a new and different pain and it rapidly gets worse, making moving around, taking deep breaths, coughing, or sneezing extremely painful. Other key symptoms are loss of appetite, slight fever, nausea, constipation or diarrhea, inability to pass gas, abdominal swelling, and sometimes vomiting.


Anyone can develop appendicitis, but it is most common in individuals from 10-30 years of age. Since its recognition as a medical condition in 1886, the prevailing theory of its cause is blockage, either by fecal matter or by lymph node swelling. However, this notion does not account for variations in incidence observed by age, gender, ethnic background, family history, geographic clustering, and seasonality. Research shows that appendicitis is much more common in industrialized nations than in developing ones. When nations such as the US and the UK worked on improving air quality, their incidence of appendicitis dropped drastically. This suggests that air quality may play a role in the development of the inflammation.

In a recent study, published in the Canadian Medical Association Journal,1 researchers gathered information from 5,191 adults in Calgary who had appendicitis, and studied the concentration of specific air pollutants for the seven days leading up to their hospitalization. The air pollutants monitored at these stations include ozone, nitrogen dioxide, sulphur dioxide, carbon monoxide, and suspended particles with aerodynamic diameters of <10μ and <2.5μ.

Results revealed that more subjects had appendectomies throughout the summer days, when people were more likely to be spending time outside or leaving windows open during times when pollution concentrations, especially nitrogen dioxide (from car exhaust) and ozone, were at the highest levels. This associated risk was greater in men, possibly because men are more likely to work outdoors, which increases the duration of their exposure to the polluted air. The researchers also note that their study did not include children, a particularly important group considering that children have a higher incidence of appendicitis and tend to spend more time outside than adults do.

This study suggests that short-term exposure to high levels of air pollution could trigger some cases of appendicitis. However, the research team suggests that more investigation is necessary to confirm whether air pollution really does have an impact on cases of appendicitis. If researchers are able to repeat these results in future studies, it could explain the link between appendicitis and its increased incidence in the industrialized world. Possibly, by improving air quality, we could prevent some future cases of appendicitis.

First published in the Inside Tract® newsletter issue 179 – 2011
1. Kaplan, GG et al. Effect of ambient air pollution on the incidence of appendicitis. Canadian Medical Association Journal. 2009;181(9):591-7.