Could Pollution Cancel Out the Health Benefits of Walking?

Even though walking is one of the best things you can do for your body, researches has shown that strolling along heavily polluted streets, may actually cancel out many of the benefits associated with walking.

A team of researchers recruited over 100 people. One third of these were healthy, the other third had chronic obstructive pulmonary disease and one third had ischemic heart disease, which is caused by a narrowing of the arteries.

Some of the people were instructed to walk for two hours per day along heavily trafficked street, while the others spent the same amount of time walking through a quiet park. Three to eight weeks later, the groups swapped routes. After each outing, researchers measured pollutant concentrations in each environment, along with a number of health markers in the participants, including lung capacity, breathlessness, wheezing, coughing and arterial stiffness, which is related to high blood pressure.

After walking through the park, researchers saw big improvements in their lung capacity and arterial stiffness. But after walking along the street people saw only modest improvements in lung capacity and a worsening of arterial stiffness, suggesting that the air quality nullified many of walking’s health

What threatens our health in daily walking?

Traffic-related air pollution has been associated with various health risks for human populations living near roadways. Understanding the relationship between traffic density and dispersion of vehicle-released air pollutants is important for assessing human exposure to near-road air pollutants. The most common pollutants are:

  • Black carbon (BC): BC is the most harmful to public health of all air pollutants. Black carbon particulate matter contains very fine carcinogensand is therefore particularly harmful. Even relatively low exposure concentrations of Black Carbon have a direct effect on the lung function of adults and an inflammatory effect on the respiratory system of children.


  • Carbon monoxide (CO): is a colorless, odorless, and tasteless flammable gas that is slightly less dense than air. Carbon monoxide is colorless, odorless, and tasteless, but highly toxic. It combines with hemoglobinto produce carboxyhemoglobin, which usurps the space in hemoglobin that normally carries oxygen, but is ineffective for delivering oxygen to bodily tissues.


  • Nitrogen dioxide (NO2): For the public, chronic exposure to NO2 can cause respiratory effects including airway inflammation in healthy people and increased respiratory symptoms in people with asthma. NO2creates ozone which causes eye irritation and exacerbates respiratory conditions, leading to increased visits to emergency departments and hospital admissions for respiratory issues, especially asthma.

Even when driving a car it is necessary to be aware of all pollutants that can harm our health. Read more in our article "Air quality on the road"