Qualité de l’air à Halifax

What is the air quality index of Halifax?

Halifax, officially known as the Halifax Regional Municipality (HRM), is the capital of the Canadian province of Nova Scotia. It lies on the east coast of Canada. In 2016, the estimated population stood at 403,000 people.

Agriculture, fishing, mining, forestry, and natural gas extraction are major industries operating in and around Halifax.

At the beginning of 2021, Halifax was enjoying a period of “Good” quality air with a US AQI reading of 31. This classification is in line with the recommendations from the World Health Organisation (WHO). The recorded level of PM2.5 was 7.6 µg/m³. With a level as low as this, doors and windows can be opened to allow the ingress of fresh air into the rooms. All types of outdoor activity can be freely enjoyed without fear.

Does the level of air quality differ in Halifax throughout the year?

The air quality deteriorates as the weather gets colder and indoor heating is needed during the colder winter months. Wood burning is particularly bad as a source of air pollution. The amount of pollution produced varies as to the dryness of the wood that is used. Normally any wood that is over two years old is dry enough to be used safely. Otherwise, kiln-dried wood is suitable.

What is the main source of air pollution in Halifax?

The main sources of air pollution in Nova Scotia come from the burning of fossil fuels for electricity generation and transportation. Residential wood burning is also a major source of air pollution in Nova Scotia.

Atmospheric ozone (O₃) is a secondary pollutant produced via complex chemical reactions involving precursors like nitrogen oxides (NO_x), Volatile Organic Compounds (VOC) and carbon monoxide (CO).

At certain times of the year, Halifax is subject to the pollution caused by forest fires, both locally and from a distance. The origin of some of these fires is from natural causes, such as lightning, but others are classed as being suspicious. The extinguishing of these fires can be very challenging due to their remoteness and the intense dryness of the area. Some fires have been burning for some time and are deeply rooted in the underlying vegetation.

A recent study found that Nova Scotia alone accounts for a quarter of the sulphur dioxide (SO₂) pumped into the air in all of Canada, owing to the continued reliance on huge amounts of coal to be burned in generating electric power. The province's power generation emits sulphur dioxide at an annual 145-kilogram-per-capita, which is more than eight times the national average and 1.35 times more than the next closest province. It has been suggested that natural gas would be a cleaner fuel as it produces far fewer pollutants than coal or heavy oil. Looking towards the future, though, wind-power has been suggested as a source of sustainable power.

What can be done to improve the air quality in Halifax?

All residents can help reduce air pollution by reducing the amount of driving, choosing more fuel-efficient vehicles and maintaining them with regular engine tune-ups and avoiding unnecessary trips. The use of public transport, cycling, walking, or carpooling will help reduce both air pollution and traffic congestion.

Air pollution can be reduced by turning off the engine when the vehicle is parked. Ten seconds of idling uses more fuel than restarting the vehicle's engine!

Cutting down on the use of small engine motors will also help reduce air pollution. By eliminating the use of small gas-powered engines such as lawnmowers, leaf blowers, chain saws, lawn and garden tractors, ATVs, snowmobiles, outboard motors and personal watercraft will also help to reduce air pollution.

The Nova Scotia Energy Strategy classifies the province's commitments to the reduction of air pollutant emissions from the generation and consumption of energy, in line with national standards. They are actively involved in reducing the amount of sulphur dioxide (SO₂), mercury (Hg) and nitrogen oxides (NO_x) emissions.

In Halifax, carbon monoxide (CO) levels are 63 per cent lower than 25 years ago, particulate matter concentrations PM2.5 and PM10 are down 50 per cent, sulphur dioxide (SO₂) levels are down 90 per cent and nitrogen dioxide (NO₂) levels are down by 20 per cent.

What are the effects of breathing Halifax’s poor quality air?

Air pollution has been shown to negatively affect humans' cardiovascular and respiratory systems. Lung tissue can be easily damaged with direct exposure to air pollutants such as ozone, potentially causing lung inflammation and impairment of lung function.

Health Canada estimates that approximately 5,900 Canadians die every year from air pollution. A 2008 study conducted by the Canadian Medical Association estimated that almost 3,000 Canadians die annually from short-term exposure to polluted air, while another 18,000 die annually due to long-term effects of air pollution. The study estimated the economic impact of air pollution to be around $8 billion, including lost productivity, health care costs, deaths and a decrease in quality of life.

Particulate matter (PM10 and PM2.5) means solid or liquid particles of smoke, dust, and other things that are suspended in the air. When air is polluted with particulate matter, these particles enter our breathing system with the oxygen that the body needs.

When the particulate matter enters the nose or mouth through the breath, the fate of each particle depends on its size, for instance, the smaller the particles, the deeper they penetrate the body. PM2.5 with a diameter of less than 2.5 micrometres is included in the 'fully suspended substances' (TSP). They are so small that the hairs in the nose fail to arrest their progress and get inside the respiratory system. They pass through our respiratory tract into our lungs where the metal elements present on the surface of the particles oxidise the lung cells, damage their DNA and increase the risk of causing cancer. Particle contact with the lung cells causes swelling, irritation, disturbance, and obstruction of airflow causing lung breathing difficulties such as COPD (Chronic Obstructive Pulmonary Disorder), Cystic Lung Disease, and bronchitis. The risk of diseases increases.

As soon as PM2.5 enters the bloodstream through the alveoli, they make them narrow by causing inflammation in the blood vessels or by making fatty scab tissue. This increases blood pressure or causes blood clots to form. Due to this, the flow of blood reaching the heart and brain can be restricted, which can lead to stroke or heart attack. In recent years, researchers have begun to notice that particulate matter pollution is also associated with a decrease in cognitive functions too.