WOODSMOKE AND AIR POLLUTION by JasoRobinson

VIEWS: 71 PAGES: 8

									WOODSMOKE AND AIR POLLUTION
Sitting in front of a roaring fire on a chilly winter night may be romantic, but
unless you have an advanced-combustion wood stove or fireplace insert,
significant quantities of more than 100 pollutants associated with
woodsmoke could be making their way into your home and the outside air.
Several of these chemicals are carcinogenic, and linked with risks to human
health and the environment.
The burning of residential fuel wood      How are these pollutants created? If     In conventional fireplaces and wood
is an important source of air pollution   you watch wood burn, you will see        stoves, large volumes of these
in Canada, according to a 1995            that flames appear over only a portion   unburned compounds are sent
emissions inventory released by                                 of the log,        directly up the chimney and into the
Environment Canada and                                                             atmosphere. One way of minimizing
other members of a                                                                 emissions from wood burning is to
federal-provincial task                                                            maintain a healthy fire—with a
force. The inventory                                                               chimney temperature of 150-200oC
shows that residential                                                              considered optimum for combustion.
fuel wood combustion is                                                            Reducing the air flow by closing
responsible for about 25                                                           dampers or burning fresh wood with
per cent of fine particu-                                                          a high moisture content reduces the
lates found in Canada’s                                                            combustion temperature and greatly
air pollution, 15 per                                                               increases the formation of creosote
cent of volatile                                                                     and atmospheric pollutants. Dark or
organic compounds                                                                    smelly smoke rising from a chimney
(VOCs), and 10 per                                                                  is an indication that the fire is not
cent of carbon                                                                     hot enough, and is releasing large
monoxide.                                                                          quantities of emissions.

Residential fuel wood combustion is                                                                        Illustration: Alain Reno
a major source of fine particulate        while smoke issues from different                                    Continued on page 2
emissions in Quebec, the Atlantic         areas.This smoke is a complex mix of
provinces and the Northwest               particulates and volatile incomplete        I     N       S      I       D       E
Territories. Ontario, Manitoba and        combustion products that are being
British Columbia also receive             distilled out of the wood.These                 Monitoring River Ecosystems:
                                                                                     3    Citizens Pitch In
significant volumes of air pollution      incomplete combustion products
from residential wood burning, which      include volatile and semi-volatile         4    Tracking Canada’s Deadly Storms
is a concern in many urban areas of       organic compounds as well as carbon
the country where usage is                monoxide, polycyclic aromatic              5    New Sensor Revolutionizing
                                                                                          Oil Spill Detection
concentrated. In mountainous regions      hydrocarbons (PAHs) and other toxic
of British Columbia, weather patterns     chemicals. Fine particulates can cause     6    Climate Change Increasing
                                                                                          Ozone Loss in the Arctic
exacerbate the problem by trapping        eye and throat irritations, headaches,
smoke near ground level in populated      allergies and aggravate cardio-            8    Endangered Turtles Struggle
                                                                                          for a Place in the Sun
valleys for extended periods of time.     respiratory problems.


       Environment    Environnement
       Canada         Canada
    Continued from cover




                                                                                                  Key features of an advanced-combustion wood stove




    An even more effective way to reduce
    pollutants is to use these clean
    burning practices with an advanced-
    combustion appliance. Such
    appliances have two simultaneous
    combustion zones—the first at wood
    level, where conventional burning
    takes place, and the second in the area        The results of the 1995 emissions            Canada, and in assisting decision-
    immediately above, where volatiles are         inventory will be helpful in making          makers in the development of
    temporarily detained by a deflector            more accurate assessments of the             guidelines aimed at reducing air
    and burned off before leaving the              environmental impacts of emissions           pollution in the future.
    combustion chamber. Advanced-                  from residential wood burning in
    combustion wood stoves certified
    under Canadian Standards Association
    or United States Environmental                      U R B A N A I R Q UA L I T Y
    Protection Agency performance
    standards reduce toxic emissions, emit
                                                          A B U R N I N G I S S U E
    80-95 per cent fewer particulates, and
    are up to 20 per cent more fuel-                Growing concerns over the health and environmental effects of wood burning in
    efficient than conventional models.             urban areas have prompted a four-month project to measure and analyze
                                                    woodsmoke emissions in Montréal. The project, which is being carried out by
                                                    Environment Canada scientists in cooperation with the Montréal Urban
    Environment Canada has helped                   Community and the provincial public health department, is aimed at improving
    promote these technologies by                   knowledge on the content and volume of woodsmoke emissions, determining
    providing support to change-out                 local exposure to toxic pollutants, and identifying meteorological conditions
    projects in communities in British              that may exacerbate the problem.
    Columbia, New Brunswick and Nova
    Scotia, where retailers provide people          Since December 1, 1998, monitoring equipment stationed at Rivière-des-
    with financial incentives to swap their         Prairies, at the east end of Montréal Island, has been collecting data on
    old wood-burning appliances for new,            particulate matter, polycyclic aromatic hydrocarbons (PAHs) and volatile organic
    high-efficiency ones. Hundreds of               compounds, as well as weather information such as wind speed and direction,
    households have made a switch as a              temperature, humidity and visibility. So far, signals received from the site show
                                                    large increases in emissions of particulate matter and PAHs after five o’clock in
    result of these projects, which also            the evening. Since there is little vehicular traffic in the area, it is likely that
    included seminars and workshops on              the main source of these emissions is wood-burning appliances.
    better burning techniques. A similar
    effort involving Environment Canada,            Scientists are planning to use the information gathered this season to develop a
    the Hearth Products Association of              woodsmoke forecasting program that will enable them to warn citizens to
    Canada and several other                        minimize wood burning in conditions where air quality is seriously threatened.
    organizations is currently running in
    Eastern Ontario.

2                                             Connecting Canadians With Their Environment
MONITORING PROGRAMS TEACH CITIZENS TO
SAFEGUARD HEALTH OF RIVER ECOSYSTEMS
Students, members of environmental organizations and other community
volunteers in central British Columbia are helping scientists monitor
the water quality of the Salmon River by collecting, identifying
and counting insects, clams, crayfish, snails, leeches, worms and
other tiny aquatic invertebrates that make the tributary their home.
This volunteer-based monitoring            enrichment or sedimentation. Some            as an early warning of potential
program—developed by scientists at         macroinvertebrates are more sensitive        water pollution problems.
Environment Canada’s National              to water pollution or other habitat
Water Research Institute in                disturbances than others. However,           Scientists working with communities
Saskatoon in consultation with local       understanding which types of                 to develop these programs are
groups and government agencies—            pollutants are involved or why               confident that these techniques can
enables people with little or no           certain types of animals are present         be applied elsewhere in the country
science background to take an active       or absent requires more information          and can play an important role in
role in safeguarding their local           than a simple count can provide.             raising public awareness about
environment by teaching them basic                                                      pollution prevention and environ-
scientific sampling techniques. And it     A second aspect of the monitoring            mental stewardship. Researchers from
provides the scientific community          program involves measurements of             the Institute are already providing
with valuable information on how
the river’s ecosystem is changing
over time.

Aquatic macroinvertebrates are
prime subjects for such studies for
several reasons. First, they are
relatively easy to sample—not only
because they are large enough to be
seen without a microscope, but also
because they are a primary food
source for many important species of
fish, and therefore abundant in most
streams. Second, because they do not
stray far during their lives, they
indicate a river ecosystem’s state of
health by revealing the effects of                                                 Volunteers collecting samples from the Salmon River, B.C.
short- and long-term environmental
variations on local conditions.            key water quality variables and the          hands-on training to and preparing
                                           sampling of algae. Once again,               an instruction manual for groups in
Once the composition of the                community volunteers are enlisted to         Atlantic Canada, so that communities
invertebrate community has been            take samples, but, in this case,             on the other side of the country will
determined, inferences can be drawn        professional laboratories perform the        be able to participate in volunteer-
about the health of the stream at the      analysis. Often, this level of               based monitoring programs and
sites sampled and, ultimately, about       monitoring is carried out in                 become more aware of local water
the extent of habitat degradation          partnership with government                  quality issues.
caused by impacts such as organic          agencies, which use the information


                                         Connecting Canadians With Their Environment                                                           3
    TRACKING CANADA’S DEADLY STORMS
    Tropical cyclones with winds that rotate at speeds of more than 103.6
    kilometres per hour, hurricanes are devastatingly powerful storms that
         usually travel over a large area during their lifespan. As they make
               their way from Africa across the Atlantic Ocean to the east
                     coast of North America and venture into the northern
                       latitudes, they undergo significant behavioural changes—
                        a phenomenon known as extra-tropical transition.

                                                  from one side of a hurricane to the                       causing widespread and intense
                                                  other—with stronger winds to the                          flooding in heavily populated coastal
                                                  east and torrential rain to the west. It                  areas and on low-lying farmland.
                                                  has also been found that, although
                                                  hurricanes weaken as they pass over                       In addition to sharing information
                                                  cooler waters, on rare occasions they                     with the international hurricane
                                                  interact with extra-tropical storm                        community through the committees
                                                  fronts and re-intensify. Hurricane                        of the World Weather Research
                                                  Hazel, which caused 81 deaths and                         Program and World Meteorological
    Meteorologists at the Canadian                $100 million damage in southern                           Organization, Canada’s Atlantic
    Hurricane Centre in Halifax, Nova             Ontario in 1954, was such a hybrid.                       meteorologists are helping to ensure
    Scotia, are on the leading edge of                                                                      public safety at home by working
    studies in extra-tropical transition, as      Although few of the two or three                          closely with the National Hurricane
    well as in the danger that storm-             hurricanes Canada’s Atlantic provinces                    Centre in Miami, Florida, issuing
    induced waves and tides—known as              average per year make landfall,                           technical and public bulletins, and
    “storm surges”—pose to coastal                considerable damage has been caused                       assisting emergency responders in
    communities.They are using complex            in the past by torrential rains and                       contingency planning. By
    computer models and data from ships’          high and forceful wind-driven waters                      encouraging land-use planners to
    logs, public archives and other historic      that sweep the coastline where the                        consider this information when
    records to diagnose these storms and          eye of the storm approaches nearest.                      developing flood plans, managing
    better understand the physics that            Pioneers in the study of storm surges,                    dikes and building coastal
    drives them. In January 1999, a scien-        Environment Canada scientists have                        infrastructure, science is helping to
    tist from China and a researcher from         created the largest database on the                       mitigate the future impacts of these
    McGill University joined the team in          subject on the Atlantic coast, using                      deadly storms.
    Halifax to contribute their expertise         archival information and forecasts to
    to these studies for the next year.           identify areas that are most vulnerable
                                                  to the effects of such a
    What they have learned, so far, is that       disaster.Water marks on
    hurricanes move more like regular             buildings from the
    winter storms in northern latitudes           devastating Saxby Gale of
    than they do down south, where they           1869—the model of a
    tend to be more erratic.They also             worst-case scenario—
    travel up to five times faster—a              indicate that ocean water
    serious concern given the fact that a         levels reached two metres                                DIRECTION OF
    large number of small boats are on            above the high-tide mark.                                HURRICANE MOVEMENT                         AFRICA
    the water during the June-to-                 With sea levels rising and
    November hurricane season.While               storms becoming more
    hurricane forecasting always requires         intense due to climate                       SOUTH AMERICA
    extreme precision due to the                  change, scientists estimate
                                                                                    Typical path of hurricanes originating off the coast of Africa; the storms
    concentrated impact of these storms,          that such a storm today              gather energy as they cross the warm waters of the Atlantic Ocean.
    it is an even greater challenge in            would cause sea levels to rise                          Above left: Hurricane Hortense made landfall in
    northern latitudes because effects vary       nearly a metre higher—                                             Nova Scotia on September 15, 1996.




4                                              Connecting Canadians With Their Environment
SENSOR A REVOLUTION IN SPILL DETECTION
Detecting spilled oil that has washed up on a remote beach can
be like finding a needle in a haystack. Because certain airborne
sensors used to track spills have a narrow field of view, it can take
hours of flight time to locate a spill and several more to carry out
the physical inspection needed to verify sensing data. In difficult
environments, such as in heavily weeded waters, along shorelines and
in ice and snow, even the most advanced sensors have proven unreliable,
leaving some spills undetected and sensitive environments and species at risk.
Beginning early this year, the world’s        including polycyclic aromatic              and classify contamination as light
most advanced system for detecting            hydrocarbons (PAHs) found in               refined, crude or heavy refined oil, as
and classifying oil spills will begin         petroleum oils—to become excited           well as estimate the percentage of oil
operation aboard a DC-3 aircraft              and give off light in the form of          coverage on either side of the flight path.
based in Ottawa. Developed with the           fluorescence. Few other compounds
help of a consortium of agencies that         in the environment show this               Factory acceptance tests conducted
                                              tendency. In addition, different classes   on the new scanning laser
                                              of oil fluoresce with different            fluorosensor have proven the
                                              intensities and exhibit different          technology capable of detecting and
                                              spectral signatures, meaning that the      classifying even minute quantities
                                              bands of colour in each class’s            (only 0.5 per cent of the total area
                                              spectrum are unique.                       illuminated) of a weakly fluorescing
                                                                                         oil on a sand background. Used
                                              SLEAF is the new generation of the         properly, this kind of precise
                                              Laser Environmental Airborne               information will help to mitigate the
                                              Fluorosensor (LEAF), which was             potentially disastrous effects of an oil
                                              developed in Canada in 1992.The            spill on sensitive marine and coastal
                                              main shortcoming of the original           environments by eliminating the
                                              fluorosensor was that it illuminated       need for costly and time-consuming
                                              an area only 10 centimetres wide           physical inspections, and by directing
Narrow bands of oil at the high-tide line     and 30 centimetres long at an              responders to sites that require
of a sandy beach
                                              altitude of 100 metres, making it easy     remediation.
includes Environment Canada and               to miss spills on beaches and
the U.S. Minerals Management                  shorelines, where oil tends to pile up
Service, the Scanning Laser                   in a narrow band at the high-tide
Environmental Airborne                        line.The new sensor is equipped
Fluorosensor (SLEAF) is the first             with a high-powered laser strong
real-time sensor able to detect and           enough to operate at an altitude of
classify oil in even the most difficult       600 metres—giving it a field of view
environments.                                 six times as large as that of LEAF.
                                              One of two conical scanning mirrors
This sensor collects fluorescence data        is used to direct the laser beam in a
from various surfaces in the marine           circular pattern, enabling it to collect
and terrestrial environment. It does          400 samples per second in a swath
this by shining a beam of ultraviolet         up to 200 metres wide. Advanced               SLEAF survey charts will include surface features,
light onto the surface of the Earth,          detection and classification                      latitude and longitude, and the survey track.
                                                                                                    The lines extending from each side of the
causing certain compounds—                    algorithms enable SLEAF to detect                   survey track represent oil coverage detected.




                                            Connecting Canadians With Their Environment                                                           5
    CLIMATE CHANGE INCREASING OZONE LOSS
    IN THE ARCTIC STRATOSPHERE
    Climate change may enhance the frequency and depth of severe
    stratospheric ozone loss in the Arctic and could delay the recovery of
    the Arctic ozone layer by a decade or more, according to an Environment
    Canada report that reviews recent science on the issue. Findings show
    the greenhouse gases that are warming the lower atmosphere are causing
    cooling in the Arctic stratosphere in spring—thereby promoting the
    formation of polar stratospheric clouds that allow ozone-destroying
                   substances to cause more damage.
                                                    Two factors make ozone destruction in the polar regions brutally efficient during the
                                                      spring. One is the polar vortex, a nearly closed circulation system that isolates the
                                                        polar stratosphere from sunlight and the surrounding atmosphere, causing it to
                                                          become extremely cold. At temperatures of -80oC or lower, a second factor
                                                            comes into play: the formation of polar stratospheric clouds.These frozen
                                                             clouds cause ozone-depleting substances that are normally stable and
                                                              therefore harmless to the ozone layer to break down into forms that are
                                                               easily broken apart by solar radiation.With the return of sunlight in the
                                                               spring, these unstable compounds release large volumes of chlorine and
                                                                bromine—powerful ozone-depleting catalysts, each molecule of which
                                                                can destroy thousands of ozone molecules before returning to the
                                                                troposphere and being removed by other chemical reactions.
                                                                                                                                              Continued on facing page




    An EC scientist takes weather measurements at Alert,
    on the northeast tip of Ellesmere Island, NWT.




                                                                                                    A computer model of the possible minimum and maximum Arctic ozone
                                                                                                            depletion until the year 2060 (Source: Arctic Ozone, 1998)




                                                                       Measurements of a single air mass as it moves around
                                                                       the Arctic vortex show how ozone concentrations decrease
                                                                       with accumulated exposure to sunlight, January 4 to
                                                                       February 9, 1992. (Source: Arctic Ozone, 1998)



6                                                          Connecting Canadians With Their Environment
                                                                                                Stratospheric ozone observatory at Eureka,
                                                                                                      on the west coast of Ellesmere Island
Continued from facing page

Most of the world’s ozone is               reduced ozone levels over southern           processes. Climate change and ozone
produced over the tropics, but it is       Canada as ozone is redistributed in          depletion should be treated not in
distributed all over the world by          the atmosphere.                              isolation, but as interrelated parts of a
winds. Ozone forms in the                                                               common strategy for moderating
stratosphere when oxygen atoms             Further monitoring and research on           the human impact on the
liberated by powerful ultraviolet          the Arctic ozone layer is necessary to       atmosphere.
(UV) rays combine with intact              understand trends and atmospheric
oxygen molecules. It is gradually
destroyed by sunlight and natural
chemical reactions, but there is                 A        L       L                 A       B         O           U           T
usually enough new ozone coming in
to replenish losses. In recent years,
excessive volumes of ozone-
                                                              S             &                   E
depleting substances released into the           SCIENCE AND THE ENVIRONMENT BULLETIN
atmosphere by human activity have
                                                  is a bi-monthly publication produced by Environment Canada to
caused ozone depletion. In six out of             provide information on leading-edge environmental science and
the last nine years, unusually low                                   technology to Canadians.
ozone values have been observed
over the Arctic during the spring                Find out more about the subjects in this issue and previous ones by
                                             visiting our S&E Web site at [www.ec.gc.ca/science]. The on-line version of
with ozone losses of up to 45 per              the Bulletin often contains additional information and graphic material
cent reported in 1997.                              and provides links to other relevant sites and documents. Many
                                                  departmental publications mentioned in the Bulletin are posted on
                                               Environment Canada’s Green Lane at [www.ec.gc.ca], or can be ordered
With lower stratospheric                                     from the Inquiry Centre at 1-800-668-6767.
temperatures spurring the more
frequent formation of these clouds              Media representatives and others interested in conducting further
and ozone-depleting industrial                 research may obtain the names and phone numbers of departmental
                                               scientists involved in these and related initiatives by contacting the
chemicals expected to be at or near                Bulletin’s editor, Paul Hempel. He can be reached by e-mail at
peak levels for the next 10 to 20            Paul.Hempel@ec.gc.ca and by telephone at (819) 994-7796. Readers are
years, the situation could worsen in         welcome to e-mail their comments and suggestions to this same address.
the coming decades. Larger
                                                       Our goal is to make S&E Bulletin as useful as possible.
depletions in the ozone will expose                               Please share your ideas with us!
highly sensitive Arctic lifeforms to                                      ISSN   1480 - 3801
significant increases in UV radiation
from the sun, and could lead to

                                        Connecting Canadians With Their Environment                                                           7
                                                                     A PLACE IN THE SUN
                                         Reaching down through a wire cage, a field
    Illustration:                     researcher carefully handles a newly hatched
    Canadian Museum of Nature
                              spiny softshell turtle. After its weight and other data
    have been noted, the hatchling gets a free ride to the next stage of its life—
    at the water’s edge. If its habitat remains undisturbed, this turtle may live to
    adulthood. Many of its number, however, haven’t been quite that fortunate.
    Spiny softshells need sandy or gravelly                      found in the Lake Champlain area of          established that a large part of the
    shoreline for nesting, but also use the                      Quebec where recovery efforts are            threat to this species comes from a
    area—often a large rock—to take in                           being carried out jointly with the           loss and degradation of nesting,
    the sun.This basking activity is                             United States.                               basking and hibernation sites. Radio
    important to researchers because it                                                                       transmitters placed on turtles have
                                                                 While there is heavy predation of            shown that they can travel distances of
                                                                 spiny softshell eggs and hatchlings by       up to 30 kilometres in a year, while
                                                                 animals such as raccoons, foxes and          some move less than half a kilometre.
                                                                 coyotes, people are the most                 This suggests to researchers that, if all
                                                                 significant problem—with one-                the right habitat elements are present,
                                                                 quarter of the nests at some sites lost      the turtles won’t move far. Further
                                                                 due to human disturbance.To help             radio tracking in future will help the
                                                                 make nesting more productive,                recovery team determine where the
                                                                 recovery team workers install wire           turtles go for the winter, enabling
    Softshells use their tube-shaped snouts as snorkels, so
                                                                 cages over the nests after they have         further habitat protection of those areas.
    they can breathe while under water.                          been laid from mid-June to July.These
                                                                 cages help prevent interference until        Starting with the 1998 nesting season,
    gives them an opportunity to observe                         the hatchlings are born some time            the recovery team, in cooperation
    the species more closely. Unfortun-                          between late August and October.             with Environment Canada, has begun
    ately, basking also attracts attention                                                                    studying the role contaminants might
    from boaters and cottagers, who may                          When they hatch, the young are               play in infertile eggs recovered from
    unintentionally disturb a nesting site.                      about the size of a two-dollar coin.         hatched or failed nests. In the
                                                                 The male of the species is olive brown       meantime, efforts continue in working
    The spiny softshell turtle was listed as                     with pronounced spots on its shell           with landowners who have spiny
    a threatened species by the                                  that are coloured a light tan in the         softshells on their property, and in
    Committee on the Status of                                   centre.The female does not have such         protecting and rehabilitating nesting
    Endangered Wildlife in Canada in                             pronounced spotting, but is the larger       sites as much as possible. So far,
    1991. A recovery team, made up of                            of the two sexes, growing to slightly        Ontario landowners have been very
    scientists from Environment Canada,                          larger than a dinner plate—but just as       receptive to habitat protection—an
    the Ontario Government and non-                              flat. Although their shells are not really   important aspect of any effort to
    governmental organizations, began                            soft, they have a leathery feel and not      protect species at risk.
    work a year later to stabilize and                           the hard slick surface found on most
    increase the size of the population.                         other kinds of turtle shells.
    Although exact numbers are difficult
    to pinpoint, estimates put 500-1,000                         As with many recovery efforts for
    softshells on the Sydenham and                               species at risk, much of the initial
    Thames rivers in southern Ontario                            work with the spiny softshell focuses
    and about the same number in other                           on determining the full extent of its
    parts of the province, such as Long                          habitat, tracking its movement,
    Point National Wildlife Area.The                             gathering data on size and general
    species has also been observed in the                        health, and sharing information. So
    Ottawa River. Less than 100 are                              far, the recovery team involved has                                     Softshell hatchlings



8                                                             Connecting Canadians With Their Environment

								
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