By: Cassandre Clermont
Good air quality is important for health, as is healthy eating and physical activity. The air we breathe allows our body to function; therefore it is essential that it is made up of healthy gases in enough quantity. On Earth, more frequent smog episodes have been linked to the increase in greenhouse gas emissions. Smog is an accumulation of air pollutants that consists mainly of fine particles and tropospheric ozone. Smog can cause many health problems, up to and including premature death. In Canada, according to a study carried out over the period from 2014 to 2016, approximately 14,600 deaths per year are caused by air pollution from human activities [6].
The mildest symptoms of short-term exposure to smog are irritation and dryness of the throat, difficulty breathing, fatigue, and excess mucus [1]. However, the more serious consequences involve an increased risk of having a heart attack and stroke [2]. In addition, long-term exposure can lead to the development of chronic cardiovascular diseases such as heart failure, atherosclerosis, hypertension and cholesterol [3]. It can also cause chronic respiratory illnesses like chronic bronchitis, asthma, and lung cancer [1]. Obviously, the people most vulnerable to these harmful effects are the elderly, young children and all people with pulmonary, heart and chronic diseases like diabetes [1]. In addition, people living or working outside in industrial and urban areas are at higher risk.
Recent studies have shown that smog mainly increases mortality from cardiovascular diseases more than pulmonary [3]. Coarse, fine and ultrafine particles from air pollution are the main compounds that cause damage to the body. Fine particles (PM 2.5) are associated with long-term mortality [4] and coarse particles (PM 10) are associated with short-term mortality [3]. These particles cause vascular oxidative stress; oxidative stress is an attack of cells by free radicals which leads to the formation of plaques in the vessels [2]. They also cause inflammation, which leads to increased clotting factors and platelet activation, which can then lead to the formation of a clot that can block a blood vessel [2]. The blockage of a blood vessel is a serious health problem that is one of the causes of infarction and stroke. A recent study published in the journal ACS Nano [5] suggests that ultrafine particles have another function; they can pass from the lungs to the bloodstream, which can cause an increased risk for the obstruction of a blood vessel.
In the event of a smog warning, it is recommended to spend less time outdoors, especially for physical work. Of course, it is also advisable to avoid contributing to smog, by using alternative modes of transport to the automobile. Also, certain foods such as Brussels sprouts, fish oil, broccoli and cauliflower can reduce the harmful effects of smog  [3].
Air pollution is therefore a worldwide phenomenon that causes premature death. In addition, it must be considered that global warming is worsening the harmful effects of smog. It is therefore essential, in the coming years, to remedy this significant health hazard.