Every year, air pollution is responsible for almost 7 million deaths, including 29% of deaths due to lung cancer.
The air pollution impact in our health
Air pollution is a significant and far-reaching threat to public health, with 99% of the world’s population breathing unhealthy air, according to the World Health Organization (WHO). 
The risks associated with air pollution are like those caused by smoking tobacco. Indeed, exposure to air pollution can lead to cancer, stroke, respiratory, cardiovascular diseases, and other health issues. Nearly half of lung cancer cases in people who have never smoked are estimated to be related to air pollution. [1,2]
Causes of air pollution
Air pollution is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.
Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution. Pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide.
Particulate matter (PM) is composed of chemicals such as sulfates, nitrates, carbon, or mineral dusts. Vehicle and industrial emissions from fossil fuel combustion, cigarette smoke, and burning organic matter, such as wildfires, all contain PM.
A subset of PM, fine particulate matter (PM 2.5), have a diameter of less than 2.5 microns and is 30 times thinner than a human hair. PM 2.5 represents a major health risk. It can be inhaled deeply into lung tissue and contribute to serious health problems.
PM 2.5 is a significant factor associated with lung cancer and has been classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC) since 2013. [1,2]
What can I do?
Taking action to reduce exposure to harmful pollutants directly reduces the risk of cancer and disease, while creating an environment that indirectly improves general health by encouraging physical activity.
Pollution is the result of both collective and individual actions. Each of us may not be able to change the world but remember each one of us has a superpower! Through our actions, we can contribute to a healthier world.
Authors: Cidália Gonçalves, Sónia Silva, Nádia Moura (Liga Portuguesa Contra o Cancro)