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What is Happening?Smog, the term given to a haze in the air, is a potential risk to health. The key smog pollutants are ground-level ozone (O3) and fine airborne particulate matter (PM). A major source of these two smog pollutants is the burning of fossil fuels in vehicles, factories, thermal power plants, and home furnaces. Soil, road dust, fires and industrial and agricultural activity also contribute to the fine particle mass. Both these smog pollutants are monitored in the valley by the Lower Fraser Valley Air Quality Monitoring Network, operated by the Greater Vancouver Regional District (GVRD) and supported in various ways by other agencies. For this Smog Indicator, three Fraser Valley monitoring sites which have data records for both ozone and particulate are used (Langley, Surrey and Chilliwack- see Map). Unlike the stratospheric ozone high above the earth’s surface that filters out harmful ultraviolet rays from the sun, ground-level ozone can be harmful to human health. Although ground-level ozone occurs naturally, excessive levels are the result of human activity. This happens when nitrogen oxides (NOx) from the combustion of fossil fuels and volatile organic compounds (VOCs) found in solvents, oil-based paints and gasoline, react in the presence of warm temperatures and sunlight. Airborne particulates are minute particles small enough to remain suspended in the air and together with other air pollutants give smog its colour. Common terminology uses PM10 to refer to all particles less than 10 microns in diameter, and PM2.5 to refer to particles less than 2.5 microns in diameter. For comparison, a human hair is approximately 70 microns wide. Regional air quality is most often assessed by comparing monitoring data to national and provincial guidelines or objectives. On the basis of this type of comparison, air quality is characterized as good, fair or poor. On days when smog levels are expected to produce poor air quality, public advisories are issued. The levels at which such advisories are issued are 82 ppb over a one-hour period for ozone and 50 µg/m3 over a 24 hour average for particulate matter. However, recent research indicates that there is no ‘safe’ or threshold level of human exposure to either ground-level ozone or particulate matter below which health effects do not occur (National Ambient Air Quality Objectives For Ground-Level Ozone and For Particulate Matter, Science Assessment Documents, 1999). Reductions in ambient levels of these smog pollutants are expected to have public health benefits. Reference Levels are defined as the lowest ambient ozone and particulate matter concentrations at which statistically significant increases in human health effects have been detected. The Federal-Provincial Working Group on Air Quality Objectives and Guidelines (1999) established Reference Levels for PM10, PM2.5 and ozone. These Reference Levels are 20 ppb 1-hour daily maximum for ozone and 25 µg/m3(PM10) and 15 µg/m3 (PM2.5) averaged over a 24 hour period for particulate (National Ambient Air Quality Objectives for Ground-Level Ozone, July 1999 and National Ambient Air Quality Objectives for Particulate Matter, 1999). Comparison of air quality data in relation to these Reference Levels therefore provides a measure of potential health risk. The percent of time each year that ground-level ozone and particulate matter data exceed Reference Levels is being tracked as an indicator of potential health risk. The analysis of the data in this manner is intended to provide the Fraser Valley residents with an informative and relevant indicator of the status and trends in their air quality.
Source: Data from Environment Canada, National Air Pollution Surveillance (NAPS) Network, Ottawa, Ontario and GVRD, Burnaby, BC. 2004. The ozone and PM10 data are from the Surrey, Langley and Chilliwack monitoring sites. Potential health risk trends are expressed as the percentage of time each year ozone and PM10 exceed the Reference Levels at the three sites. (Reference Levels are: ozone 20 ppb one hour daily maximum, PM10 25 µg/m3 24 hour daily average). In 2003, smog levels exceeded the Reference Level in the Fraser Valley about 44% of the time for the ground-level ozone pollutant and about 7% of the time for fine airborne particles (PM10). The graphed data show that since 1994 there has been no discernable trend in the potential health risk from ozone but there appears to have been an increase in the potential health risk from PM10 levels since 2000. Since higher levels of smog pollutants pose higher risks, the annual profiles of potential risk are graphed in increments of 10 above the Reference Levels. For example, the higher ozone levels of 40 ppb or more were exceeded an average of 5% of the time between 1994 and 2002. By comparison Prince George, Williams Lake and Kelowna exceeded 40 ppb on average 8-10% of the time while in the eastern Canadian cities of Kingston to Sault Ste. Marie it was 11 to 12% of the time (see comparison data for ozone and PM10). Any increases, particularly at the higher risk levels, can be identified for assessment and action. As subsequent years of data are added to the established baseline, this indicator will track long term trends in smog levels.
Source: Environment Canada, National Air Pollution Surveillance (NAPS) Network, Ottawa, 2004. For more information on the data set see Graph Data. During the period of 1994 to 2002, ozone levels in the Fraser Valley exceeded the Reference Level (20 ppb) on average 36% of the time. This is generally comparable to other cities in BC and Canada for that time period. Between 1995 and 2002, particulate matter (PM10) levels in the Fraser Valley and in the Vancouver - Burnaby area exceeded the Reference Level (25 µg/m3) on average 5-6% of the time. This was lower than other cities in BC [Kelowna (12%), Williams Lake (20%) and Prince George (25%)] or in the Prairies (29 - 40%) or the Windsor - Montreal corridor (25 - 42%). For more information on PM10 levels observed in other BC communities consult BC Ministry of Water, Land and Air Protection indicator on air quality impacts from fine particulates. It can be seen in the graphs above that ozone levels are highest during spring and summer. This is particularly so when temperatures are warmest and the air is stagnant. Particulate (PM10) concentrations can be high at varying times of the year as they are primarily determined by meteorological conditions and within valley sources. However, it is known that fossil fuel combustion in mobile sources contributes mostly to the finer particulate size ranges such as PM2.5. In 2000, it was estimated that 45 percent of Fraser Valley PM2.5 emissions came from mobile sources (GVRD and FVRD 2002). Because these smaller particles have been implicated in adverse health effects, monitoring for PM2.5 has been recently initiated at a number of Fraser Valley sites. At present, only the Chilliwack monitoring site has a period of record for PM2.5 dating back to mid 1995. These data show that between 1996 (first full year of data) and 2003, PM2.5 exceeded the Reference Level of 15 µg/m3 between 0.3 to 3.1% of the time. As the PM2.5 data base grows for the Fraser Valley, future updates of this indicator will include and place more emphasis on the trends in PM2.5. Why is it Happening?The Fraser Valley encompasses the GVRD and that portion of the FVRD bounded by the Coastal Mountains to the north and the Cascade Mountains to the southeast. These geographical features, along with the summer sea breezes off the Strait of Georgia, restrict air-flow patterns and contribute to the area’s smog problem. Summer-time weather conditions and the atmospheric pollutant emissions from human activities are the other factors that allow the formation and accumulation of air pollution. The poorest air quality usually occurs during the summer when a high pressure system produces clear sunny skies, high temperatures and light local winds. Temperature inversions trap pollutants near the ground and light winds transport them throughout the Fraser Valley where they undergo photochemical reactions to form smog. Click to view the Smog Animation.
Most of the smog in the Fraser Valley is generated locally. In ozone formation, the major sources of VOCs are motor vehicles, the evaporation of gasoline from gas pumps and from solvents. Oxides of nitrogen are produced mainly by the high temperature burning of fuels, such as by internal combustion engines, certain manufacturing industries and factories. Ozone concentrations tend to be dominated by transportation sector emissions. A significant amount of the total mass of pollutants contributing to ground-level ozone comes from light-duty vehicles.
The graph above shows how total vehicle kilometers traveled has increased by almost 50% since 1985. The region continues to experience population growth with increased vehicle numbers and a trend to higher emission sport utility vehicles. There were 1.29 million registered motor vehicles on Greater Vancouver roads as of 2004 and that number is expected to increase by 60% in the next 20 years. Statistics Canada reported that in 1996 almost 600,000 people in the GVRD drove vehicles to work with 14% of those commuting trips exceeding 20 km. While vehicles are being used more, a 1999 TransLink survey of travel by GVRD adult residents found that only about 12% of trips involve public transit (TransLink 2000). Annual use of public transit dropped to 64 trips per capita in 2000 from 67 trips in 1991 (GVRD 2001). Why is it Significant?Smog is harmful to people when inhaled into the lungs. Each year the effects of smog cause people to die prematurely, suffer temporary or long term health effects or just be inconvenienced. New research has shown that it is not possible to define a ‘safe’ smog level. Health effects start to occur at very low levels of both particulate matter and ground-level ozone and increase steadily as concentrations increase. The elderly, small children and people with respiratory or cardiovascular disease, are more likely to feel the effects of smog. But, even healthy adults develop symptoms at high levels of exposure. Recent studies have demonstrated an association between ozone exposure and development of asthma while other studies implicate other smog pollutants including particulate matter. Canadian and U.S. researchers have also found new evidence that inhaling smog has a direct effect on the heart and blood vessels. A recent assessment by the BC Lung Association ( Bates et al. 2003) focuses on understanding the relationship between exposure to air pollutants and resulting illness and premature death. Elevated ozone concentrations are associated with increased incidence of respiratory disease in humans (National Research Council 1991). Short term exposure to ozone can irritate the eyes, nose and throat producing symptoms like coughing or difficult breathing. After a few days of repetitive exposure respiratory symptoms subside but the damage may continue to occur deep in the lungs. Asthmatics are more sensitive to air pollutants in general and asthma attacks increase substantially with higher ozone levels (National Ambient Air Quality Objectives for Ground-Level Ozone - Science Assessment Document 1999). The evidence is strong for an association between hospitalizations for respiratory diseases and exposure to ozone at levels commonly encountered in Canada. Health Canada has determined from Canadian respiratory hospitalization data that every 10 ppb increase in the one-hour maximum ozone level equates to a 1% increase in respiratory hospital admissions and a 0.6% increase in mortality. Similarly, increases in hospital Emergency Department visits are associated with increases in ambient ozone concentrations. These risk studies included 16 Canadian cities where the mean ozone concentrations were well below the current objective of 82 ppb (1-hr maximum). A 1996 study of 58 Fraser Valley farm workers over two summer months revealed lung capacity declined about five per cent the day following exposure to even low ambient ground level ozone levels (Brauer et al. 1996). Population groups with high levels of exertion and who spend large amounts of time outdoors may be particularly susceptible to ozone effects. It has also been inferred that repeated inflammation from ozone exposure over a lifetime can produce sufficient respiratory tissue damage to reduce lung function in later life (Tepper et al. 1991). Epidemiological evidence also strongly suggests a link between particulate matter and aggravated respiratory symptoms related to coughing and difficult breathing, chronic bronchitis, emphysema and decreased lung function. These problems are specific to the heart-lung system and can lead to lost school and work time, restricted activity, asthma attacks, emergency room visits, hospital admissions, and death. Even at low concentrations of PM, such as those experienced currently in the Fraser Valley, there are potential risks to human health. These health effects have focused on increasingly smaller particles (PM2.5) which may remain in the air for days or even weeks and can easily reach the deepest recesses of the lungs. In 1995, Fraser Valley annual health costs due to PM10 were estimated at $420 million to $900 million (BC MELP 1995).
In 1995, a UBC Dept. of Medicine researcher estimated that increases in fine particle pollution cause 82 premature deaths in BC every year, 146 hospitalizations due to asthma, lung and heart disorders and 354 extra emergency room visits for asthma, chronic bronchitis or emphysema (Vedal 1995). For each 10 µg/m3 increase in PM10 there is an estimated 0.8 % increase in hospitalizations, a 1.0 % increase in emergency room visits, a 9.5% increase in days of restricted activity and a 4.1% increase in school absenteeism due to respiratory symptoms. Although only a relatively small segment of the population is susceptible to the very adverse effects of fine particle pollution, a sizable group can be affected by the less adverse effects. Based on a more recent study of the air quality of the lower mainland (Brauer et al., July 2000), Medical Health Officers expressed the view that between 15 and 150 deaths per year in the Fraser Valley may be attributable to air pollution. This is even though the levels of air pollutants (including ozone and PM10) in the Fraser Valley are generally lower than most of the Western US cities of similar or larger size. The pollutants of smog produce adverse effects on more than the health of humans. The yield and quality of agricultural crops such as the Fraser Valley's high-value crops of strawberry, lettuce and broccoli are negatively impacted by ozone enrichment (Janzen et al., 1999). Increased exposure of strawberry plants to ozone reduces the number and weight of good fruit resulting in fruit losses as high as 15% in the Fraser Valley. Ozone causes leaf injury to broccoli and the severity of leaf damage was found to be directly related to ozone enrichment (Janzen et al., 1999). Crop damage in the Fraser Valley due to ozone is estimated to be in the millions of dollars. Ozone can also damage synthetic materials, cause cracks in rubber, accelerate fading of dyes and speed deterioration of some paints and coatings. A 1993 and 1994 study in the Fraser Valley indicated fine particle pollution was responsible for visibility frequently being degraded below publicly acceptable levels in the central valley (Pryor and Barthelmie 1996). Visibility conditions that affect views in the valley have an influence on both residents and tourists, and impacts on tourism can result in economic implications for the region. McNeil et al., 2000 estimated that for a single extreme visibility event tourist revenues losses could amount to about $7.45 million in the Greater Vancouver area and $1.32 million in the Fraser Valley area. What is Being Done?Jurisdiction over air quality in the Fraser Valley is a shared responsibility of GVRD, FVRD, the British Columbia Ministry of Water, Land and Air Protection (BC MWLAP) and Environment Canada. All these agencies work collaboratively and with the North West Air Pollution Authority which has responsibility for the US side of the air shed. The GVRD has a detailed Air Quality Management Plan for the District and issues a daily Air Quality Index (AQI) report for communities in both FVRD and GVRD parts of the Fraser Valley. In cooperation with the other agencies, Environment Canada provides daily reports on the air quality and weather history of the Fraser Valley and other areas of BC. It also issues daily forecasts for maximum ground-level ozone for the Fraser Valley during the summer months. On days when smog levels are expected to be high, special advisories are issued by the three agencies. The Burrard Thermal plant is required to cut emissions during serious ozone episodes . A wide range of initiatives aimed at reducing smog are underway. The GVRD's Air Quality Management Plan includes more than 50 emission reduction measures for many source sectors. Industrial point sources, area sources such as residences and the industrial/commercial/institutional sectors, and on-road and off-road mobile sources are all included in the Plan. Through adoption of the Plan in 1994, the GVRD committed to lowering annual emissions of common air contaminants by 38%. Additional information on the Plan and the progress being made can be found at the GVRD website. The Government of Canada has passed new regulations to reduce air pollution resulting from tailpipe emissions. These include regulations to reduce the level of sulphur in diesel fuel (January, 1998) and gasoline (June, 1999) and the level of benzene in gasoline (November, 1997). In May 2000, Environment Canada also announced a national program with immediate and long term actions to reduce pollutants that contribute to smog and declared particulate matter toxic under the new Canadian Environmental Protection Act (CEPA 1999). More recently (February, 2001) Environment Canada announced a 10 year regulatory road map for cleaner vehicles and fuels, initial measures to reduce smog causing emissions from industrial sectors, improvements to the cross country network of pollutant monitoring stations and expansion of the public reporting by industry on pollutant releases (click for more details). In April 2001, the federal government firmed up this road map through an action plan called Interim Plan 2001 on Particulate Matter and Ozone which announced actions underway or contemplated to reduce emissions of particulate matter and the formation of ground level ozone. For example, current regulated vehicle standards will be replaced by new standards that will reduce NOx emissions by approximately 88 per cent from passenger cars and up to 95 per cent for light-duty trucks, including sport/utility vehicles (SUVs). New regulations are also to be introduced to reduce sulphur in on-road diesel fuel to 15 parts per million by 2006, down from today's average of 320 parts per million. The BC AirCare Program, the first air care program in Canada, requires all light-duty vehicles in the Fraser Valley to be inspected for exhaust emissions and emission-control systems. On January 1, 2001 AirCare II was implemented, incorporating the latest innovations in emissions systems technology and test procedures to ensure AirCare continues to make a difference in Fraser Valley air quality. Health Canada continues to undertake national epidemiological studies on health effects and risk factors related to smog. Environment Ministers identified PM and ozone as priorities for Canada-Wide Standards. Federal, provincial and territorial governments participated in the development of Canada Wide Standards (CWSs) for both fine particulate matter PM2.5 and ground -level ozone. The CWSs are in the form of ambient air management targets (Ozone 65 ppb, 8 hr average and PM2.5 30 µg/m3, 24 hr average), with schedules for achieving the target levels by 2010. Environment Ministers endorsed these standards at their June 2000 meeting. These CWSs will be an important first step towards the long term goal of minimizing risks to human health and the environment. Canada has many regions where air quality is better than the levels set out in the CWS. However, there is no apparent lower threshold for health effects. Therefore, Environment Canada will continue to implement practicable pollution prevention and best management practices that have been identified as the best course of action by the Government of Canada and other jurisdictions.
Petroleum refiners lower the volatility of gasoline sold in the Fraser
Valley during the summer months and most service stations in the GVRD
have been retrofitted with gasoline-vapor recovery systems to contain
VOC vapours associated with storage tank loading. Use of ethanol in gasoline
has the potential to improve the urban smog problem by reducing hydrocarbon
emissions (VOCs). There are about 3.5 billion litres of gasoline sold
in BC each year and the amount of ethanol currently being used in
In August of 2001, under the GBEI Clean Air program, a major scientific air quality field study, called Pacific 2001 was undertaken at various locations in the Fraser Valley. It involved over 130 researchers representing federal, provincial and local governments, private research institutes and the university community from Canada, USA and the United Kingdom. The study's overall objective was to provide a better understanding of the sources, formation and distribution of PM and ozone in the Fraser Valley. A better understanding will help provide credible guidance on developing appropriate future strategies to reduce the risks to human health and the environment associated with these pollutants. It will also assist in the development and evaluation of regional PM computer models (used to support policy development) and to predict both PM and ozone formation. On October 22, 2003, the British Columbia Ministry of Water, Land and Air Protection (BC MWLAP) and Environment Canada, released a report on particulate matter concentrations in BC. The findings in this report can help Lower Fraser Valley agencies and interested parties in planning initiatives and strategies to reduce PM levels.
For more information contact: Peter.Schwarzhoff@ec.gc.ca Check the following sites for additional information on this indicator: Environment Canada web sites:
Other federal government web sites:
The following Web sites are not under the control of Environment Canada (EC) and they are provided solely for the convenience of users. Environment Canada is not responsible for the accuracy, currency or the reliability of the content. Environment Canada does not offer any guarantee in that regard and is not responsible for the information found through these links, nor does it endorse the sites and their content. Users should be aware that information offered by non Government of Canada sites that are not subject to the Official Languages Act, and to which Environment Canada links, may be available only in the language(s) used by the sites in question. Regional web sites:
Others:
For references used in this indicator click here. |
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