Qualité de l’air à Castlegar

What is the current level of air pollution in Castlegar?

Castlegar is the second-largest community in the West Kootenay region of British Columbia, Canada. It is situated at the confluence of the Colombia and Kootenay Rivers in the Selkirk mountains. The 2016 census estimated the population to be approximately 8,000 people.so it is not a large city.

During the middle of 2021, Castlegar was experiencing a period of air quality that was classified as being “Unhealthy for sensitive groups” with a US AQI reading of 104. This United States Air Quality Index number is calculated using the levels of six of the most commonly found air pollutants, namely, nitrogen dioxide, sulfur dioxide, ozone, carbon monoxide and both sizes of particulate matter, being PM2.5 and PM10. It can be used as a standard when comparing air quality in other cities around the world. If data is unavailable for all 6 pollutants, a figure can still be calculated by using what figures there are. For Castlegar, both sizes of the PM pollutant were recorded. PM2.5 was 36.7 µg/m³, whilst PM10 was 61 µg/m³. The World Health Organization (WHO) has a recommended level of 10 µg/m³, so with this figure, it can be seen to be over three times the recommended level, although no level is considered to be safe.

With pollution at this level, the given advice would be to stay indoors and close all doors and windows to prevent the ingress of more polluted air. The use of an air purifier would be beneficial if one is available.

Avoid exercising outside until the quality improves and if venturing outside is unavoidable, then wearing a good quality face mask is essential. The table that is published at the top of this page should help with that decision or download the AirVisual app for constant updates as to the state of the air on your mobile device.

Is the level of air pollution in Castlegar consistent throughout the year?

Air quality is very volatile and therefore can easily change quickly because it is influenced by several things. According to the 2020 figures which were published by IQAir, it can readily be seen that the worst month for air quality was during September when the recorded figure was 56 µg/m³, which firmly placed it in the “Unhealthy” category. Any figure between 55.5 and 150.4 µg/m³ is classified as such. During November, the air quality was “Good” when a figure of 10.8 µg/m³ was recorded. For the remaining 10 months of the year, Castlegar achieved the target figure of less than 10 µg/m³. This figure is suggested by the World Health Organization (WHO) as a figure for cities to work towards, although no level of air pollution is safe. The months when the air quality was at its best were May and June when the figures were 4 µg/m³ for both months. Looking at the overall figures, it appears that from April until the end of August is the time of year when air quality is at its best. Unfortunately, there were no records kept before 2020 when the average mean reading was 10.8 µg/m³ which is slightly above the WHO target figure. This figure is quite surprising because of the restrictions imposed by the COVID-19 situation. Many vehicles were temporarily unused as their drivers were not required to work from the office, instead, they were furloughed and allowed to work from home. This had the effect of drastically reducing pollution within the city center. Many small factories and non-essential production units were also temporarily closed which again lead to an improvement in air quality.

What are the sources of this air pollution in Castlegar?

There are many sources of air pollution. Wood smoke from home heating has been the leading contributor to PM2.5 pollution in British Columbia; however, smoke from wildfires has had an increasing influence over the past few years. Due to the general state of climate change and the fact higher temperatures are becoming more regular, wildfires seem to be more prevalent than ever before. There were many times during the summer of 2018 when Castlegar’s readings exceeded the province’s 24-hour air quality PM2.5 objective of 25 µg/m³. Wildfire smoke from forest fires in California, Oregon and Washington states often engulfs British Colombia which turns the sun into an orange ball. The scale of pollution can be seen through some figures. A recorded figure of PM2.5 was 463.7 micrograms per cubic meter when a value of 25 is what is considered to be a safe level. On a scale of 1 to 10, Castlegar would be a 10+, indicating a very high health risk.

Following record consecutive seasons of wildfires in British Columbia, interest in the impact of wildfires has increased, especially as the frequency and severity of fires are expected to increase. In 2018, British Columbia recorded its worst wildfire season as 2,115 fires broke out and 1.35 million hectares were burned. These numbers exceeded those of the 2017 wildfire season (which was previously the worst season in terms of area burned), in which more than 1.22 million hectares burned. In 2018, wildfires in British Columbia accounted for about 60 percent of the total area burned in Canada, compared to an average of 7 percent for the period 1990 to 2018.

Fires play an important role in the health, diversity and renewal of forests. However, they emit greenhouse gases, pose risks to human health and safety and can have serious consequences and lead to economic disruption. An estimated $ 615 million was spent on management and firefighting activities in 2018.

Other sources include prescribed burning, heavy-duty diesel vehicles, and industry.

Can anything be done to improve air quality in Castlegar?

The Smoky Skies Bulletin is a type of public advisory to report on the changing nature of wildfire smoke. It is issued when areas of the province are being impacted or have reasonable potential to be impacted by wildfire smoke within 24 to 48 hours. These bulletins are based on available pollutant concentrations information, satellite information, smoke forecast models and visual observations, and are not intended to manage local emission sources. They are used for information purposes only. They were first issued in 2017 and are issued between 1st May and 30th September which is considered to be the main part of the year affected by wildfires.

What are the problems created by wildfires?

For a fire to start, three elements must be present: heat, fuel and oxygen. Together they form what is called the "fire triangle". The heat is the spark or the source that causes the fuel to ignite. It can be caused by people, such as lighting a match, or by natural causes, such as lightning. The fuels are vegetation, such as trees, leaves and twigs on the ground or other materials that can burn. Oxygen is a component of the air necessary for combustion. These three elements must be present for a fire to ignite and continue to burn. If only one or two of these components is present, a fire cannot start.

To control or extinguish a fire, at least one element of the fire triangle must be removed. Extinguishing a fire - either containing or extinguishing the fire - is successful when the fire triangle is broken by removing heat, fuel or oxygen.

An uncontrolled forest fire can devastate everything in its path, spreading for miles, crossing rivers and roads. Each year, between 60,000 and 80,000 forest fires occur, destroying between 3 and 10 million hectares. While forest fires have different consequences on the environment, depending on their importance and frequency, the causes are also diverse.

Lightning is attributed to be the main cause of the outbreaks of forest fires of natural origin. For example, it represents nearly 30 percent in Quebec! 43 percent of forest fires caused by humans are linked to carelessness (carelessly discarded cigarette butts, garbage dumps, burning). They can also occur as a result of power surges and damage to power lines.

Forest fires increase the levels of carbon dioxide in the atmosphere, contributing to the greenhouse effect and climate change. In addition, the ash destroys much of the nutrients and erodes the soil, causing flooding and landslides.

The use of chemicals in firefighting adds another problem to the already dramatic consequences of forest fires. According to a recent study by the Higher Council for Scientific Research (CSIC), the chemicals in “flame retardants " used to extinguish fires accumulate in the soil for years and stunt the natural growth of native species.

What are the detrimental effects of air pollution in Castlegar on our health?

Even strong, healthy people can experience health impacts due to polluted air including respiratory irritation or breathing difficulties during intense exercise or strenuous outdoor activities. The actual risk of adversative effects depends on your current health status, the pollutant type and concentration, and the length of exposure to the polluted air.

High levels of air pollution can have immediate effects such as adding stress to the heart and lungs by making them work harder in order to supply the body with the amount of oxygen it needs.

Some cells can quickly become irrevocably damaged in a relatively short time and pre-existing cardiovascular and respiratory illnesses can become aggravated.

Long-term exposure can lead to the accelerated aging of the lungs leading to loss of capacity and a marked decrease in their functional ability. Diseases such as asthma, bronchitis, emphysema, and possibly cancer easily develop under these circumstances.

Air is a mixture of many gases but its main constituents are: dioxygen (21%) and dinitrogen (78%) and other gases (1%).

Man directly or indirectly causes air pollution by releasing polluting substances into the atmosphere. Our lungs filter an average of between 10,000 to 15,000 liters of air each day, and this can be as much as up to four times more for a working athlete. Thus, the quality of the air we breathe has consequences on our health, but also on the environment.

Atmospheric pollution refers to the increasing concentration in the air of polluting gases and particles. Gases polluting the atmosphere are emitted by natural sources (volcanoes, vegetation, erosion, etc.) but also produced by humans (transport, industries, heating, agriculture, etc.). In cities, the increase in these pollutants is mainly linked to the emission of toxic gases from motor vehicles and factories. Among the toxic elements and particles constituting air pollution are;

• sulfur dioxide (SO₂) which is mostly absorbed in the throat, causes coughing and shortness of breath.
• ozone (O₃) and nitrogen dioxide (NO₂) which penetrate, as far as the bronchi; they can pass in our organism at the level of the pulmonary alveoli and can be responsible for the aggravation of asthma attacks.
• particles, the largest of which (PM10) are retained in the nose or throat, they make us cough or sneeze, the others (less than 0.001 mm) go even further into the respiratory system as they are so small they can easily bypass the body’s defense system and travel as far as the alveoli which are found at the base of the bronchial tubes. From here they can easily transfer into the bloodstream and travel throughout the body.

It is difficult to distinguish the short-term effects from the long-term effects, the effects linked to background pollution from those linked to pollution peaks and the quantities from which the pollutants act. Many diseases are due to air pollution, such as lung cancer, asthma, pneumonia.

Acute bronchitis is caused by weakening and irritation of the bronchi to atmospheric pollutants, which stimulate the presence of a virus or bacteria. Chronic obstructive pulmonary disease (COPD) is a complication of chronic bronchitis. It is permanent and not reversible.

The number of cases of cancers of the respiratory tract attributable to atmospheric pollution is difficult to estimate, insofar as this pathology is associated with several risk factors (tobacco smoke, radon (radioactive gas), emissions from diesel engines and gasoline). The number of cases identified remains low compared to other diseases associated with air pollution.

Coughs, rhinitis, and bronchiolitis in children are among the respiratory pathologies that can be triggered or worsened by air pollution. Among heart diseases, it is a risk factor for myocardial infarction, cerebrovascular accidents (stroke) and angina pectoris.