Learning Module | Health THREATS
Chapter Two
2. Air Pollution
Introduction to Air Pollution
Air pollution is a complex mixture of particles. Sources of air pollution include both solid and liquid particles suspended in the air (known as Particulate Matter), various gases (such as ozone, nitrogen dioxide, and carbon monoxide), and biological molecules. [1]
Although largely in Canada we are able to enjoy clean air, some significant examples of air pollutant sources include vehicle emissions, industrial emissions (for example, sawmills, pulp and paper mills), in addition to smoke produced from indoor and outdoor burning. [2]
The Ozone
Two components of air pollution that pose a significant risk to health include Particulate Matter and Ground Level Ozone. [3]
Particulate Matter.
Particulate matter (PM) is a general term for a mix of solid and liquid particles suspended in air.
The impact of climate change on PM is less understood than ozone, but one notable source of PM is from wildfire smoke. [4]
PM2.5 penetrates deep in the lungs, in addition to being able to enter the bloodstream – resulting in primarily cardiovascular and respiratory impacts. [5]
PM is considered to be the air pollutant of greatest concern in B.C. [6]
Ground level ozone.
High levels/ chronic exposure to ground level (or tropospheric) ozone is responsible for adverse health effects, such as premature mortality, and a variety of morbidity effects. [7]
In Canada, average ground level ozone levels have increased by 10% between the years 1990-2010 (although peak ozone levels are declining). [8]
Warm temperatures catalyze the production of ozone, and the warming effects of climate change will likely function to further increase levels of ground level ozone. [9]
Images retrieved from: http://publications.gc.ca/collections/collection_2019/sc-hc/H144-51-2019-eng.pdf
“Air pollution is a threat to health in all countries, but it hits people in low- and middle-income countries the hardest.”
GLOBAL SCALE
Air pollution is considered to be the largest environmental risk to health on a global scale, [10] far exceeding others, such as lack of clean water and sanitation. Disparities are highlighted, with lower-income countries facing higher PM2.5 levels. It was responsible for 8.7% of global deaths in 2017, primarily due to its contribution to respiratory and cardiovascular mortality and mortality. [11]
In 2020, 23% of COPD deaths, 12% of ischemic heart disease deaths, and 12% of stroke deaths were attributable to daily exposure to household air pollution. This was also responsible for 44% of pneumonia deaths in children less than 5 years old, [12]
IN CANADA
In comparison to the rest of the world, Canada has one of the lowest fine particle air pollution exposure levels, but its effects are not insignificant.
Air pollution is associated with approximately 15,300 premature Canadian deaths per year, with 1,900 in British Columbia. [13,14]
The cost of health impacts attributable to air pollution is $120 billion, approximately 6% of Canada’s GDP in 2016. [15]
In one of the largest analyses to date, ambient air pollution exposure was associated with decreased lung function and increased COPD prevalence. This association was stronger in those with lower incomes. This was further confirmed by a 2019 study, finding that ambient air pollution in Canada was associated with lower lung function, with 27% of participants living in Vancouver, BC. [16,17]
HEALTH IMPACTS
Effects from Particle Pollution.
Smaller particles, (including PM2.5) deposit deeper in the lungs, in small airways and alveoli. Healthy individuals rely on clearance/ detoxification methods include nasal filtering (bypassed if mouth breathing), cough/ sneeze reflex, muco-ciliary clearance, and phagocytosis to remove foreign debris from the lungs. [18]
Chronic or high dose PM exposure can lead to inflammation, bronchoconstriction, and resulting cell injury and death. [19,20]
A study in Utah found that years when the local steel mill (a significant source of PM) was closed, there was a 2-3x reduction in children’s hospital admissions for asthma and bronchitis compared to years when the mill was open. [21]
Effects from Aeroallergens.
Pollen production, allergenicity, and length of pollen season tends to increase when exposed to raised temperature and CO2 levels.
Ragweed, which is one of the most common allergens in Canada, has increased its growing season by over 3 weeks since 1995. [22]
This resulting increased aeroallergen exposure is expected to increase both the incidence and prevalence of respiratory allergies and asthma. [23]
Cardiovascular Effects.
PM exposure is associated with increased risk of cardiovascular morbidity and mortality. [24]
Inhaled particles cause alveolar inflammation, which “spills over” into circulation, causing endothelial disruption and systemic inflammation. [18,24]
A study by Nowka et al. found that over half of cardiovascular disease (CVD) patients were unaware of the association between air pollution and CVD. Additionally, over 90% of these patients stated their healthcare provider had never discussed this association, or strategies to reduce exposure. [25]
Read more about the impact climate change has on cardiovascular health here.
Keeping AT RISK populations in mind can lead to conversations addressing modifiable risk factors, and the prevention of adverse health outcomes.
Populations especially vulnerable to the effects of air pollution
The elderly.
The young.
Those with chronic respiratory or cardiac disease.
ADDRESSING MODIFIABLE RISK FACTORS & PREVENTING ADVERSE HEALTH OUTCOMES
Educate patients about the health effects of air pollution.
There is confusion surrounding the connection between climate change, air quality, and patient health. [26]
Understanding on the effects of climate on air pollutants and aeroallergens, their effects on respiratory and cardiovascular health, and how to reduce these exposures will equip you to educate patients and reduce vulnerability. [19]
For example, patient education about lengthening allergy seasons, and areas high risk for exacerbations allows for patients to take initiative for their health. Asthma education programs have been shown to reduce asthma related emergency department visits and hospitalizations. [27]
Discuss adaption strategies with patients.
Consider proactively starting discussions with those most vulnerable to the effects of air pollution, such as children, the elderly, and people with chronic respiratory and cardiovascular diseases. [28]
When asking about patient lifestyle, focus on modifiable risk factors that can help minimize air pollutant exposure. Some examples include:
Their activities (time of day, location, exertion level)
Location of residence
Safety of work environment, and any exposures to air pollutants
Possible integration of air cleaners, masks or medications [18]
Some common adaptation strategies include:
Reduce/ stop smoking
Limit fireplace and woodstove use
Monitor outdoor air quality (via the Air Quality Health Index from Health Canada, or the Plume app)
Choose less strenuous activities during times of poor air quality
Reduce time spent near high traffic areas [29]
Share resources with patients.
BC Air Quality Health Index - Find out current air quality in BC
FNHA Wildfire Information - Access the most recent provincial wildfire resources
Plume Lab’s Air Quality App - Keep up to date with air quality on your mobile device
Outdoor Air Quality - A primer for BC physicians with resources to inform patients
Patient Resource: Air Pollution - Guide to indoor and outdoor air quality
Advocate for air quality improvement.
Having this foundation of knowledge can allow you to advocate for expansion of current research on changing pollutant levels, allergic sensitization, and overall health trends shaped by climate change.[19]
Advocacy work that increases awareness of the impacts of air pollution can lead to more funding for systems to combat these outcomes. One example is improved warning systems for physicians and the public to forecast and be aware of times of reduced air quality or increased pollen levels, so preventative measures may be taken. [30]