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Pollution & air quality

Outdoor air quality

Climate change

Climate change means long-term changes in the Earth's climate system. Scientists expect that climate change could mean more days of warm temperatures and high humidity. This is bad news- smog has always hurt human health the most on hot and humid days; if we have more of these days, the health effects of smog will get worse.

Varying temperatures can also change the amount of allergens that get released from trees and other plants. As the allergens mix with other air pollution, people with asthma and other lung diseases could get worsening symptoms.

Read the Lung Association's Backgrounder on Climate Change (PDF)

Canada's energy use

Canada's per capita energy use is one of the highest in the world. Many factors increase our use of energy: our cold climate, wide distances from cost to coast to coast, travel needs, a high standard of living, energy-intensive industry base and relatively low energy prices.

A 1996 Environment Canada statistic estimated that 72% of our energy comes from the combustion of fossil fuels, 12% hydroelectricity, 10% nuclear power, 6% wood, and a negligible amount from alternative sources of power such a wind and solar energy. Of the energy consumed in Canada, transportation uses about 27%, industry uses about 39%, and the remaining 34% is used in agriculture, homes and businesses.

Fossil fuels and pollution

Our use of fossil fuels in vehicles, industry and energy generation contributes to air pollution and climate change. If Canadians used less fossil fuel, we'd see benefits to the environment and to health. One way of reducing our use of fossil fuels is to try alternative energy sources.

What are fossil fuels?

Fossil fuels are made up of decomposed plant and animal matter which store energy that was converted from sun energy more than 65 million years ago. Fossil fuels consist of coal, oil/petroleum, and natural gas. Of these, world reserves of coal are the most abundant, followed by natural gas and then oil. It is estimated that cost-effective reserves of oil will run out in the next century. In 1992, natural gas surpassed oil as the leading fossil fuel consumed in Canada. Fossil fuels are naturally located underground. Coal is a black-coloured rock-like substance, oil or petroleum is a thick dark liquid, and natural gas which is mostly methane, is colourless, usually odourless and is lighter than air. Crude oil must be refined to produce gasoline, diesel fuel, aviation fuel, home heating oil, ship oil and oil to burn in power plants to make electricity.

How to fossil fuels harm the environment and human health?

The combustion of fossil fuels (and to a lesser extent, biomass material) releases many air pollutants that harm our health. These include sulphur oxides (SOx), nitrogen oxides (NOx), volatile organic compounds (VOCs), particulate matter (PM), carbon monoxide (CO) and toxics such as mercury. Besides direct effects on lung and heart health, some of these chemicals also combine in the atmosphere to produce acid rain, ground-level ozone and smog.

As well, fossil fuels are a major contributor to atmospheric carbon dioxide (CO2 ) levels, one of the most important greenhouse gases affecting climate change. Most scientist agree that climate change will have a significant effect on human and ecosystem health over the next century.

What are some alternative energy sources?

Hydroelectricity: Canadian consumption of hydropower is above the world average. Hydroelectric projects are expensive to build but have low operating costs, and longer life spans than coal or nuclear plants. They use a renewable resource, emit no air pollution or greenhouse gases but significantly impact natural ecosystems and man-made landscapes during construction. The environmental impact of several small hydroelectric facilities is less than an equivalent large facility.

Nuclear Power: Nuclear power is dependent on the very concentrated energy in uranium. Nuclear power stations are expensive to build and it has been estimated that nuclear generated electricity is more expensive than major alternatives such as hydro and coal. Nuclear reactors produce no greenhouse gases and the entire fuel cycle produces about one-sixth as much CO2 per unit of electricity as does the use of coal. The challenge of safe storage of nuclear waste and the threat (albeit statistically small) of unintended release of radioactive material has resulted in lack of public support for this technology. Despite the relatively unused capacity to acquire energy from nuclear technology, uranium is not a renewable resource. Uranium is not plentiful enough, using today's reactors, to provide for total global energy needs for more than about ten years!

Wood: If the wood used for energy comes from a carefully managed woodlot, wood is a renewable energy resource. Most of Canada's use of wood for energy is achieved by the forest products industries which use waste wood to produce steam and electricity for their own energy needs. More than 6% of Canadian single family homes use wood as the primary source of heat, and another 13% use wood to complement their heating systems. Wood burning can hurt human health; it releases CO2 and particulate matter into the air. High-efficiency wood stoves release less pollution indoors and out.

Wind Power: The use of wind for energy has increased greatly over the past decade because of its technical reliability and declining cost. Wind can either provide mechanical power, such as for pumping water, or can generate electricity. It is a renewable resource and is a clean source of power. At present, in Canada, wind power is best suited to remote regions which lack conventional resources but its use in other areas is increasing. The challenges to increased use of wind power is the amount of land that would be needed to house windmills sufficient for commercial needs, and a change in mind set that would encourage the restructuring of the power grid to accept wind power energy. Several areas of Canada are well suited to further develop this resource.

Solar Power: "Active solar technology" converts radiation from the sun into thermal energy which can heat air or water. "Photovoltaic technology" converts sunlight directly into electricity using solar cells made from semi-conductor materials. This latter technology is expensive and cost effective for large applications only in remote areas where traditional power costs are high. Continuous advances in this technology are expected to increase its use in the future. Solar energy is a renewable resource and is a clean source of power. For this reason, and to offset monthly power costs, an increasing number of people are using solar power to augment traditional power sources in their homes and businesses.

Biomass Energy: Energy stored in plant material can be converted into usable power by combustion. Wood is one commonly used source of biomass energy. Grasses, such as switchgrass, have excellent potential. Pelleted switchgrass can be produced at an estimated cost equivalent to $.25/litre of heating oil, and has the same energy efficiency as oil used in a high efficiency furnace. Switchgrass, like most biomass products, requires extensive use of land. Although biomass products are renewable resources, combustion does produce some air pollution. It has been estimated that switchgrass produces 90% less CO2 than does an equivalent amount of coal. Biomass can also be converted into liquid fuels such as ethanol which can be used to run motor vehicles.

Geothermal energy: The earth absorbs solar radiation. Ground-source heat pumps use either earth or groundwater as a source of heat in winter and as a reservoir for heat in the summer. Installation of heat pumps can cost an amount equivalent to installing a well. Cost recovery occurs after only a few years as the heating/cooling efficiency is 170-260% (this means that you get heat energy with no energy input). An increasing number of residences and businesses are using this technology to supplement traditional energy sources.

What you can do:

Global energy demands continue to rise. In order to provide humans with energy needs over the long term, we need to encourage lifestyle changes that reduce our per capita use of energy, reduce our use of non-renewable energy sources, particularly fossil fuels which cause air pollution and contribute to climate change, and use energy sources that are renewable and non-polluting.

There are many things that you can do as an individual, as a family, community or business:

  • Car pool, use a bicycle or walk to work.
  • Insulate and ventilate your house.
  • Use a clothesline instead of the dryer.
  • Turn down your thermostat.
  • Petition your electric power company to use cleaner technology.
  • Be thoughtful with your use of water, especially hot water.
  • Use landscaping techniques to make the most use of sun and shade to heat or cool your house.
  • Reduce, reuse and recycle.

For more information on climate change, see the New Brunswick Climate Change Public Education and Outreach Hub

The connections between climate change, air quality and respiratory health

The Intergovernmental Panel on Climate Change report released on February 2, 2007 indicated virtual scientific certainty that the climate is changing at a rate faster than has been experienced for all years that humans have records, and that the cause of this rapid change is human activity.

Human contributions to climate change

The principle human cause of climate change is the burning of fossil fuels - coal, oil, gas, diesel, etc. A second leading cause is intensive agriculture, which releases methane into the atmosphere. The principle greenhouse gas produced from fossil fuels is carbon dioxide, but methane is also released. These gases rise in the atmosphere and when located in the upper atmosphere they act like a blanket, preventing the sun's heat that has already reached the earth from dissipating to outer space.

Climate change will increase average global temperatures. Increased temperatures result in a faster movement of water through the water cycle, and warmer air can hold more water vapour. The result of this is that the increased temperature is also related to unusual precipitation and wind patterns. Thus climate change and weather are linked.

Fossil fuels also release air pollutants

Burning fossil fuels also releases air pollutants- sulphur oxides (SOx), nitrogen oxides (NOx), volatile organic compounds (VOCs; there are many), carbon monoxide (CO), and other toxic compounds. SOx and NOx react in the atmosphere to produce particulate matter. NOx and some VOCs react in the atmosphere to produce ground-level ozone. Particles and ozone together make smog, which can travel long distances on the prevailing winds, or can be trapped close to the ground during a weather inversion (often with little wind). Thus air pollution and weather are linked. 

All of these air pollutants can cause serious health effects. Health effects are best understood for particulate matter smaller than 2.5 µg/m3 and ground-level ozone. There is no safe level of exposure to either of these substances. Increased levels of exposure may cause congestion, difficulty breathing, asthma attacks and occasionally death. PM2.5 is associated with an increase in heart attacks. Long-term exposure to PM2.5 is associated with low birth weight and reduced lung development in children. Health risks are higher in vulnerable populations - the very young, the elderly, those with pre-existing respiratory disease (such as asthma or COPD) or cardiovascular disease, and those exercising or doing strenuous work in locations with elevated air pollution.

Impacts of climate change

Climate change will have many impacts. These include an increase in global average temperatures, changes in precipitation and weather patterns, droughts, forest fires, desertification or floods, changes in growing seasons and ability to grow crops, changes in food and water supply and safety, changes in the distribution of wildlife and plants, changes in the distribution of certain disease-causing agents, changes in ocean temperatures and current patterns, sea level rise, increased storm surges and salt water intrusion into fresh water reserves, loss of infrastructure, displaced populations of people, socio-economic challenges.

Specifically with respect to respiratory health, the following impacts are now occurring or may occur in the future:

  1. An increase in air pollution in certain regions, especially downwind of emission sources. With rising temperatures, air pollution may increase as a result of increased use of air conditioners, refrigerators, and freezers, which can cause power plants to burn more fuel. In those regions that have air pollution associated with warm weather (i.e. locations that have their warm weather carried on southerly winds coming from heavily industrialized areas) a greater number of hot days will also mean a greater number of days with elevated air pollution and associated deleterious impacts on health. 

    The atmospheric chemistry that forms ground-level ozone and secondary particulate matter (smog) is complex. These reactions are driven in part by photochemical influences, and temperature does not directly affect the formation of these substances. Temperature can affect the precursors of smog, but care should be exercised when making direct connections between temperature and an increased rate of chemical reactions.

    There have been an increasing number of instances where people have been exposed to the combination of unusually high temperatures and elevated air pollution. Days with these combined threats are likely to become more frequent as a result of climate change. High temperatures, especially over several days, and elevated air pollution have resulted in high mortality rates in some regions, for example in France in 2003 where thousands of deaths were attributable to air pollution and heat.

  2. An increase in forest fires in some regions, as a result of drier conditions. Burning wood releases particulate matter, carbon monoxide, polyaromatic hydrocarbons (PAHs) and many other toxic chemicals, which make breathing difficult, reduce the immune system defenses against respiratory infections, and can cause heart attacks. Long term or repeated exposures can cause cancer.

  3. An increase in mould growth, and possibly a change in the types of moulds in regions affected by elevated levels of precipitation. Changes in precipitation patterns will cause unusual floods and water intrusion in buildings which are not built to withstand heavy rains and winds. Moisture accumulation within buildings creates ideal conditions for mould growth. Exposure to mould is known to cause asthma in some individuals. 

    Species of mould previously unusual in Canada have been found in some locations, such as British Columbia. Exposure to Cryptococcus gattii in certain forested areas has resulted in a low incidence of infection in people and other animals. Rarely, some people have fever, aches, and respiratory problems which can be severe.

  4. An increase in certain types of plants and their pollen. Increased levels of carbon dioxide in the atmosphere and increased temperatures have been shown to foster the growth of certain plants, such as ragweed, and result in increased pollen production. This will lead to an increase in the frequency and severity of asthma and allergy attacks.

  5. Changes in the distribution of deer mice infected with hantavirus. The variant of Sin Nombre virus (SNV) in the United States and western Canada can cause a respiratory distress syndrome in people. Contact with the urine and fecal material of infected mice can result in infection in humans. Changes in precipitation and drought can change predator/prey relationships which in turn affect the distribution of mice.

  6. Warmer marine water may favour the growth of certain algae responsible for "red tides", which sometimes produce harmful toxins. Recent evidence associates an increase in asthma attacks during red tides in some southern states such as Florida. The alga off the coast of Florida isKarenia brevis. Toxins released from these are carried as aerosols into the air and cause irritation of the nose and throat and exacerbate asthma attacks. This alga is not found off the coast of Canada, but other red tide algae do grow here, and it is possible that warming waters could extend the range of K. brevis.

  7. Less likely to occur in Canada, is the direct transmission of malarial parasites. Certain species of malaria cause respiratory symptoms, including Plasmodium vivaxwhich occurred naturally in Canada until the late 1800s. A warming climate may extend the range of the mosquitoes which are able to transmit malaria. However it is likely Canada's surveillance, control and medical systems (which effectively terminated transmission of malaria in the late 1800s) would limit any impact in Canada.

Possible negative air quality impacts of certain actions to reduce greenhouse gases

As we take action to reduce our production of greenhouse gases, some reduction strategies may also cause greater air pollution, for example:

  1. Biomass burning. Biomass such as wood and other plant material is considered to be "carbon neutral" when burned as an energy source because the plant absorbs approximately as much CO2 while it grows as it releases when it is burned. However, many units that burn biomass, including even the best wood stoves, have insufficient controls to eliminate toxic air emissions. Thus policies recommending biomass burning as strategy to reduce GHGs should not be supported until technology is advanced and regulations are in place to greatly reduce the air emissions.

  2. Energy efficiency measures in buildings that only focus on insulation and draft reduction without proper ventilation. Sufficient ventilation is essential to prevent mould growth and will assist with reduction in radon. Exposure to certain moulds is known to cause asthma in susceptible individuals. Radon is the leading cause of lung cancer in non-smokers. The Canadian guideline for radon in buildings has been reduced from 800 Bqs/m3 to 200Bqs/m3, thus triggering a need to test buildings and remediate if necessary.

  3. Switching from gasoline to diesel-fueled vehicles. Diesel is a more efficient fuel than gasoline and for each kilometer driven diesel produces fewer greenhouse gases. Combustion of diesel however produces many more toxic air pollutants than combustion of gasoline. While it is possible to reduce particulate emissions by using low-sulphur diesel and particle filters on the exhaust system, it is more difficult to reduce other toxic emissions from diesel exhaust.

Positive air quality impacts from actions to reduce greenhouse gases

Unlike many of the air pollutants released when fossil fuels are burned, carbon dioxide cannot be easily removed using "end of pipe" technology such as scrubbers, bag houses, filters etc. Thus until new carbon-capture technology is produced, the only way to reduce carbon dioxide emissions is to reduce the demand for energy through energy efficiency measures, burn fossil fuels more efficiently, or switch to other sources of power such as wind, solar, hydroelectric or tidal. Even nuclear power, with its other environmental and safety considerations, produces little CO2 and has lower air emissions. Selecting any of these mechanisms to reduce carbon dioxide will also greatly reduce the emission of air pollutants.

In contrast, traditional actions to reduce air pollutants have used "end of pipe" technology, or selection of low sulphur fuels to reduce SOx emissions. However, these actions do not reduce emissions of greenhouse gases. 

Any new directions for reducing either air pollutants or greenhouse gases must take all emissions into account so as to reduce both types. The best measures to combat climate change will also positively impact air quality, either directly by reducing air pollutant emissions or indirectly by reducing the negative impact of climate change on air quality. 

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