Acetaldehyde and Air Pollution

What do ALDH2 Deficiency, the cause of "Asian Glow", and air pollution have to do with each other? Both can pose serious threats to your health, and both involve a dangerous, carcinogenic compound called acetaldehyde.

ALDH2 Deficiency is a genetic enzyme deficiency present in about 40% of people of East Asian descent. People with the deficiency are unable to break down acetaldehyde, a compound that builds up in your body when you drink alcohol, which results in an alcohol flush reaction, sometimes known as Asian Glow.

In addition to building up in your body when you drink alcohol, acetaldehyde is also a toxic pollutant found in the air we breathe. It should come as no surprise that people who are chronically exposed to high levels of acetaldehyde in the air show symptoms associated with alcoholism. Initial exposure to high levels of acetaldehyde in the air cause eye, skin and respiratory tract irritation. Studies of rats who were exposed to high levels of acetaldehyde in the air they inhaled have shown increased occurrence of tumors in their nasal and throat passages.

Plants produce acetaldehyde when they respirate, and it is a very common compound used in pesticides, herbicides, pharmaceuticals, dyes, plastics and the manufacturing of many other products. Acetaldehyde is difficult to avoid completely, however, there are certain things that increase the amount of acetaldehyde in the air. In addition to its use in manufacturing many different products, acetaldehyde is present in the biggest contributors to air pollution: car exhaust, tobacco smoke, coal refining, and waste processing. Indoor fireplaces and wood-burning stoves are also major contributors to high acetaldehyde air concentrations inside the home, where acetaldehyde levels can often be significantly higher than outdoors. In short, acetaldehyde is everywhere and we are breathing it in all the time.

While acetaldehyde may be ubiquitous in the air we breathe, people who live in large urban cities are exposed to much higher levels. The more air pollution there is, the more acetaldehyde there is. This is bad news for people living in large cities like Los Angeles and Beijing, which consistently have high levels of air pollution. Of the 187 hazardous air pollutants they are required to control, the EPA lists acetaldehyde in the top 30 urban air pollutants that pose the greatest potential health threat in urban areas. The US Department of Health and Human Services claims acetaldehyde as “anticipated to be a human carcinogen” based on its 2016 Report on Carcinogens.

If all of the toxins we are exposed to in air pollution are bad for our health, why the concern about acetaldehyde specifically? This brings us back to ALDH2 Deficiency. Most people are aware of Alcohol Flush Reaction (Asian Glow), which is caused by a mutated ALDH2 enzyme, but there are other more serious health issues that can arise in people with the deficiency. In addition to the immediate discomfort when drinking alcohol, there are also long term health risks that are caused by the buildup of acetaldehyde in the body. These include increased risk of cancer and liver damage. 

Recommendations for those with ALDH2 Deficiency

People who have ALDH2 Deficiency should be even more concerned about their everyday exposure to acetaldehyde. Exposure to air pollution creates negative health effects for everyone, but people with ALDH2 Deficiency have the extra burden of being unable to effectively break down one of the most dangerous of those toxins: acetaldehyde.

Due to this, those with ALDH2 Deficiency should be careful to avoid major acetaldehyde sources when possible. If you live in an urban area with high air pollution, acetaldehyde is not very simple to avoid. Getting out of the city when possible, and choosing to exercise in parks or surrounding nature rather than in the city can be very beneficial, since we breathe heavily when exercising. Try to avoid having fires inside the home, which is one of the biggest contributors to indoor acetaldehyde. 

Avoiding other sources of acetaldehyde is important as well. To do this, you can avoid smoking and limit foods and beverages high in acetaldehyde like ripe fruit, coffee, tea, and artificial flavors. Limiting alcohol consumption will help reduce exposure to acetaldehyde. Finally, avoiding diets high in sugar can be very important, as this leads to increased acetaldehyde production in the stomach.

References: 

United States Environmental Protection Agency. 2000. Health Effects Notebook for Hazardous Air Pollutants: Acetaldehyde - CAS 75-07-0 Hazard Summary. 

National Research Council (US) Committee on Emergency and Continuous Exposure Guidance Levels for Selected Submarine Contaminants. Volume 3. Washington (DC): National Academies Press (US); 2009. 2, Acetaldehyde. 

NTP (National Toxicology Program). 2016. Report on Carcinogens, Fourteenth Edition.; Research Triangle Park, NC: U.S. Department of Health and Human Services, Public Health Service.