Breathing Danger: How Air Pollution Causes Lung Cancer

You may be aware that smoking cigarettes and exposure to secondhand smoke can lead to lung cancer, but did you know inhaling other air pollutants also threatens your health? Unlike tobacco smoke, other substances and contaminants in the air are not immediately noticeable, requiring a significant concentration (in color or smell) to catch our attention. Excessive, frequent exposure to such particles can trigger pulmonary diseases, including asthma, pneumonia, chronic obstructive pulmonary disease (COPD), and today’s topic of discussion: lung cancer.


Suspecting the Health Consequences of Air Pollution

Air pollution’s potential to cause various pulmonary complications has been making headlines since the 19th Century, when scientists noticed “smog” (a combination of smoke and fog) in big cities like London and New York resulted in several deaths. In addition, researchers noted a marked difference in lung cancer cases between air-polluted cities and rural areas, prompting further investigation.

A 1978 environmental health study suggested a synergistic relationship between cigarettes and air pollutants in causing lung cancer, given the rising incidence of pulmonary-related mortalities in England. Even King George VI, a heavy smoker, succumbed to lung cancer at the age of 56.

However, at the time, the scientific and medical communities lacked concrete evidence on the mechanisms by which ambient (outdoor) air pollution magnifies the consequences of smoking on human health. According to the above study, in the absence of smoking, the combined effect of all atmospheric carcinogens is not accountable for over 5 cases of lung cancer per 100,000 individuals each year in European populations.


Confirming the Link Between Air Pollution and Lung Cancer

Fast-forwarding to recent years, scientists have established a connection between air pollution and lung cancer. According to the World Health Organization (WHO), “air pollution is associated with a broad spectrum of acute and chronic illness, such as lung cancer, COPD, and cardiovascular diseases.”

Specifically, ambient air pollution is responsible for about 16 percent of all lung cancer deaths worldwide, 25 percent of COPD-related deaths, 17 percent of heart disease and stroke, and 26 percent of mortalities due to respiratory infections.


Explaining the Vulnerable Nature of the Lungs

To understand how atmospheric pollution and fine particulate matter affects the lungs, we will first specify what PM2.5 is and how it affects the respiratory system.

Fine particulate matter, or PM2.5, can have harmful effects on the lungs when inhaled. These tiny particles, measuring 2.5 micrometers or smaller in diameter, are small enough to bypass the body’s natural defense mechanisms in the upper respiratory tract and penetrate deep into the lungs.

When you breathe in PM2.5 particles, they can cause inflammation and damage to your lung tissue, leading to a range of respiratory problems. For example, they can aggravate pre-existing respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD), causing coughing, wheezing, and shortness of breath. Long-term exposure to PM2.5 also increases the risk of lung cancer, as well as other life-threatening conditions like heart disease and stroke.

According to many researchers, PM2.5 particles may cause health issues by triggering oxidative stress and inflammation in the lungs, as well as impairing immune system functions. To protect respiratory health and reduce the risk of associated health problems, doctors recommend reducing exposure to PM2.5 and other air pollutants.


Types of Fine Particulate Matter

Some examples of particle pollution or harmful PM2.5 include:

  • Dust and dirt, including soot from the road, agricultural practices, and construction activities.
  • Wildfires, as smoke and ash from a fire can produce high levels of PM2.5 particles.
  • Combustion sources, such as emissions from motor vehicles, power plants, industrial processes, and wood-burning stoves.
  • Chemical reactions, including those that occur in the atmosphere, which can generate secondary particles from pollutants like sulfur dioxide, nitrogen oxides, and ammonia.

It is worth mentioning that the composition of PM2.5 varies depending on its source, and some particles may be more harmful than others. However, exposure to any form of PM2.5 can have negative health effects on the respiratory system and overall health.


Lung Cancer Incidence Due to Air Pollution

According to the results of a 2019 socioeconomic analysis conducted in 295 counties in China from 2006 to 2014, the relationship between PM2.5 and lung cancer is more prevalent in urban areas with low economic and educational status.

In 2022, another systematic review and meta-analysis of cohort studies noted the long-term effects of outdoor air pollution. Upon examining 409,945 individuals between 1991 and 2011, the researchers found that long-term exposure to air pollution had a pooled risk ratio for lung cancer and COPD mortality of 1.08. In other words, people residing in areas with polluted air are more likely to develop pulmonary diseases, including lung cancer. 

Both studies mentioned originate in the Republic of China, as the country’s struggle with poor air quality ensues. According to IQAir, out of 131 countries, China is the 25th most polluted country worldwide. While Chad, Iraq, and Pakistan are the top three most polluted destinations, there are more studies on the subject by Chinese researchers due to science and technology in Mainland China being one of the most competitive in the world.


Workplace Pollution and Lung Cancer Development

The study of industrial pollution and its impact on human health has been a topic of concern for several decades. Through the years, researchers have identified a number of byproducts from industrial waste, all of which could lead to lung cancer and premature death. These include:


1. Benzo[a]pyrene

In 1974, a study conducted in Los Angeles, California, investigated the link between lung cancer and exposure to benzo[a]pyrene and other aromatic hydrocarbons. These chemicals are common in the petrochemical industries, and evidence suggests that they may have a synergistic effect with tobacco use in causing lung cancer.


2. Inorganic Arsenic

Similarly, exposure to arsenic air pollution raised lung cancer-related deaths among employees in the smelting and refining industries, all of whom dealt with inorganic arsenic, copper, lead, and zinc.


3. Waste Gas Emission

Today, many of us are aware that waste gas emissions from industrial sites contribute to the development of several cancers. A 2018 retrospective study conducted between 1983 and 2010 found a positive connection between gas emissions and malignant disorders, including cancer of the colon and rectum, prostate, kidney, bladder, thyroid, and lung. The byproducts responsible for increasing risks for these cancers include industrial soot, dust, sulfur dioxide, and other gaseous pollutants.

These studies highlight the importance of reducing industrial pollution and implementing effective measures to mitigate the potential health risks associated with exposure to chemicals and byproducts.


Treat Lung Cancer Before It’s Too Late

Don’t wait any longer. If you have lung cancer, seeking immediate medical attention is crucial to improve your chances of recovery. Act now and take charge of your health.

Click here for our blog Disclaimer.