ENVE 4003

1
ENVE 4003

• AIR POLLUTION - INTRODUCTION
• Overview, definitions, issues, air quality
  objectives.
• Atmospheric issues and air pollutants,
• sources and definitions of pollutants,
• Health effects,
• Air quality standards

2
AIR POLLUTION

• What is it that is not a poison? All things are
  poison and nothing is without poison. It is the
  dose only that makes a thing poison Paracelsu
  s, 1493-1541
• Air pollution is the presence of undesirable
  material in air, in quantities large enough to
  produce harmful effects
• human health
• vegetation
• property
• global environment
• climate change
• aesthetics

3
Atmospheric Issues

• Acid rain
• Smog
• Ground-level ozone formation
• Stratospheric ozone depletion
• Global climate change
• Human health effects

4
Acid Rain
Acid deposition is a general term that includes
more than simply acid rain. Acid deposition is
primarily the result of emissions of sulphur
dioxide (SO2) and nitrogen oxides (NOx) that can
be transformed into dry or moist secondary
pollutants such as sulphuric acid (H2SO4),
ammonium nitrate (NH4NO3) and nitric acid (HNO3)
as they are transported in the atmosphere over
distances of hundreds to thousands of kilometres.
5
Smog

• Smog refers to a noxious mixture of gases and
  particles that often appears as a haze in the
  air. It has been linked to a number of adverse
  effects on health and the environment
• The two primary pollutants in smog are
  ground-level ozone (O3) and particulate matter
  (PM). High levels of smog are typically
  associated with the summer due to the presence of
  sunlight and warmer temperatures. However, the
  smog problem actually occurs throughout the year,
  with winter smog (due to particulate matter
  contributions rather than ozone) being a serious
  concern when stagnant air causes a build up of
  pollutants in the air. This is usually caused by
  increased wood heating and vehicle usage in the
  winter months.

6
Stratospheric Ozone Depletion

• Stratospheric ozone depletion refers to the
  degradation of the earth's ozone layer and its
  ability to shield ultraviolet (UV) radiation from
  the Earths surface. Pollutants, such as
  chlorofluorocarbons (CFCs), destroy ozone (O3) in
  the stratosphere. These pollutants were more
  widely used in the past, but continue to be
  accidentally released from refrigeration and air
  conditioning systems, or come from using some
  solvents and foams.
• The result is a thinning of the ozone layer,
  particularly in the Polar Regions. Any loss of
  ozone in the stratosphere will allow more
  ultraviolet radiation to reach the earth's
  surface, which has many significant impacts on
  human and environmental health, such as increased
  incidence of sun burns.

7
Ground level ozone formation

• Stratospheric ozone depletion is a different
  issue than ground level ozone. In the case of
  stratospheric ozone, the concern is the loss of
  ozone in the upper atmosphere which protects us
  from ultraviolet radiation. However, the concern
  for ground level ozone is quite the opposite as
  we wish to reduce its abundance in the lower
  atmosphere. Ground level ozone degrades our air
  quality, impacting human and plant health, and is
  the major component of smog. Unfortunately,
  ground level ozone cannot move or be shipped to
  the stratosphere.

8
Climate Change

• Climate change refers to changes in the climate
  or long-term, average weather for a particular
  location. Climate change can be caused by natural
  processes, such as the change in the suns
  strength, and also by human activities, in
  particular those that alter the chemical
  composition of the atmosphere through the
  build-up of greenhouse gases (GHGs).
• Collectively, GHGs act like a blanket and trap
  heat that comes from the earth. This blanket
  effect is natural and an essential part of life
  on earth. However, atmospheric concentrations of
  GHGs have grown significantly since
  pre-industrial times largely because of fossil
  fuel use and permanent forest loss, and are
  leading to accelerated changes in our climate.
  Wind patterns, precipitation, storm events, and
  temperatures will all be affected and will, in
  turn, impact life on earth.

9
Pollutants

• SO2
• NOx (NO and NO2)
• CO
• Pb
• PM (PM10, PM2.5, ultrafine)
• VOCs
• CFCs

• O3
• CO2
• POPs
• Hg

10
Criteria Air Contaminants and Related Pollutants

• CAC, in particular, refer to a group of
  pollutants that include
• Sulphur Oxides (SOx)
• Nitrogen Oxides (NOx)
• Particulate Matter (PM)
• Volatile Organic Compounds (VOC)
• Carbon Monoxide (CO) and,
• Ammonia (NH3)
• In addition,
• Ground-level Ozone (O3) and
• Secondary Particulate Matter (PM)
• Are often referred to among the CAC because both
  ground-level ozone and secondary particulate
  matter are by-products of chemical reactions
  between the CAC.

11
Basic Questions

• Which are the pollutants involved in each of
  the atmospheric issues?
• or,
• Which atmospheric issues are associated with each
  of these pollutants?
• How are they involved?
• What are the main sources of the pollutants

12
(No Transcript)
13
Figure 1.1 de Nevers

• Sources - Atmospheric phenomena - Receptor Effects

14
AIR POLLUTANTS

• Gases (CO, NOx, SO2, VOCs)
• Particulate Matter (PM, PM10, PM2.5, TSP)
• ash, dust, smoke, mist
• Primary found in the atmosphere in the same
  chemical/physical form as when it was emitted
  from its source (CO, SO2, some VOCs, some PM)
• Secondary Formed in the air as a result of
  physical/chemical transformations of primary
  pollutants (ground-level ozone, some PM, some
  VOCs)

15
Figure 8.9 (8.11) de Nevers

• Atmospheric PM size distribution

16
SOURCES OF AIR POLLUTANTS

• Combustion coal, oil, wood, biomass
• Stationary sources power plants, space heating
  in buildings
• Mobile sources (transportation)
• motor vehicles, off-road vehicles, ships,
  trains
• Industrial processes
• metal smelters, manufacturing processes
• Agriculture
• Natural sources, volcanoes

17
SOURCES OF AIR POLLUTANTS

• Point power plant stack, industrial plant stack
• Line a highway
• Area a landfill, domestic furnaces in a
  metropolitan area, motor vehicle emissions in
  a metropolitan area
• Volume an industrial plant complex, segments of
  a highway treated as volume sources
• Considerations of scale may lead to a change in
  the definition of a particular source

18
HEALTH EFFECTS OF AIR POLLUTANTS

• Short-term, high concentration exposures leading
  to acute effects
• Long-term, low concentration exposures leading to
  chronic effects
• Dose-response relationship
• Threshold type
• No-threshold type

19
CONCENTRATION, DOSE, EXPOSURE

• Dose C V
• C concentration of pollutant, mass /volume
• usually a function of time
• V volume of inhaled air
• dV/dt, rate of inhalation is a function of
  bodily activity
• Integrated Dose ? C (dV/dt) dt
• Exposure ? C dt

20
Figure 2.1 de Nevers

• Types of dose-response relationship

21
Thresholds

• NOAEL, no observed adverse effect level
• levels which indicate a safe, lifetime exposure
  level for a given chemical from long-term
  toxicological studies
• LOAEL, lowest observed adverse effect level
• The lowest dose in an experiment which produced
  an observable adverse effect

22
POLLUTANTS AND HEALTH EFFECTS

• Relation between elevated concentrations of
  pollutants and respiratory problems, morbidity
• Relation between elevated concentrations of
  pollutants and daily deaths, mortality
• Relation between elevated concentrations of
  pollutants and lifetime cancer risk
• Populations at risk, the young, the elderly,
  people with respiratory ailments

23
HEALTH EFFECTS ASSESSMENT

• Animal studies
• expose animals (mice, rats) to the pollutant of
  concern under controlled conditions and observe
  effects, extrapolate results to humans
• Epidemiology
• observe effects in populations of similar
  characteristics except for exposure to the
  pollutant of concern

24
Figure 2.3 (2.4 ) de Nevers

• Mice, ozone dose response

25
Figure 2.4 (2.5 ) de Nevers

• Epidemiology for SO2 exposure and respiratory
  disease in children

26
PROTECTION OF HUMAN HEALTHTable 2.3 de Nevers

• Occupational health and safety
• Short Term Exposure Limits (STEL)
• Time Weighted Averages (TWA)
• National Ambient Air Quality Objectives (NAAQO)

27
Table 2.B1 State of Canadas Environment 1991

• Canadas national objectives regarding ambient
  air quality

28
Table 2.B2 State of Canadas Environment 1991

• How Canadas national objectives regarding
  ambient air quality relate health and
  environmental effects

29
Canada-wide standards

• In 1998, the federal and provincial environment
  ministers (with the exception of Quebecs) signed
  the Canada-Wide Accord on Environmental
  Harmonization, under which they agreed to develop
  Canada-Wide Standards (CWS) for certain
  pollutants that threaten environmental and human
  health.

30
CWS Current Status

• Ministers have endorsed the following Canada-wide
  Standards
• fine particulate matter
• ground-level ozone
• benzene
• mercury from incineration and base metal
  smelting.
• dioxins and furans for waste incinerators and
  pulp and paper boilers burning salt-laden wood
• petroleum hydrocarbons in soil
• mercury in lamps and dental amalgam waste
• dioxins and furans emissions from iron sintering,
  and steel manufacturing.

31
CWS Current Status

• Additional CWSs are under development for
• dioxins and furans emissions from conical waste
  burners and
• mercury emissions from electric power generation.

32
Canada-wide standards

• PM2.5
• A CWS for PM2.5 of 30 µg/m3, 24 hour averaging
  time, by year 2010
• Achievement to be based on the 98th percentile
  ambient measurement annually, averaged over 3
  consecutive years
• Ozone
• A CWS of 65 ppb, 8-hour averaging time, by 2010
• Achievement to be based on the 4th highest
  measurement annually, averaged over 3 consecutive
  years

33
Air Quality index, AQIhttp//www.airqualityontari
o.com/science/background.cfm

• an indicator of air quality, based on hourly
  pollutant measurements of some or all of the six
  most common air pollutants SO2, O3, NO2, TRS,
  CO, PM2.5
• 0 32 Good
• 32 49 Moderate
• 49 99 Poor
• 99 lt Very poor
• At the end of each hour, the concentration of
  each pollutant that the AQI station monitors is
  converted into an AQI sub-index. The pollutant
  with the highest sub-index defines AQI.