Lecture 6: Air Pollution

Question 1

T/F
pollutants can be from natural sources

Answer 1

true
eg fires/ volcanoes

Question 2

primary pollutants=

Answer 2

pollutants emitted into the enviro in a form that can be directly harmful, or can react to form harmful substances
eg. ashes

Question 3

secondary pollutants=

Answer 3

harmful substances formed when primary pollutants react with constituents of the enviro (often atmosphere)
eg. tropospheric ozone

Question 4

point sources of outdoor air pollution=

Answer 4

emanates from a discrete location (eg a power plant)

Question 5

non-point sources of outdoor air pollution=

Answer 5

emanates from diffuse points, many sources (usually moving)
- eg. planes, most modes of transportation

Question 6

what is CEPA?

Answer 6

Canadian Environmental Protection Act

• created in 1999 (implemented in 2000) to regulate the production & use of toxic substances

Goals:
- reduce pollution
- protect enviro
- protect human health

Question 7

What 4 categories does CEPA cover for air pollutants?

Answer 7

1. criteria air pollutants: pollutants for which max allowable [ ] have been established
2. persistent organic pollutants (POPs): volatile compounds that have long residence times
3. heavy metals: dense metals, toxic in low [ ]
4. toxic air pollutants (everything else) eg CFCS

Question 8

SO2 falls under which category of air pollutants?
- produced how?

Answer 8

criteria air contaminants
- smelly, colorless gas
- produced primarily from fossil fuel combustion

Question 9

NO2 falls under which category of air pollutants?
- produced how?
- contributes to?

Answer 9

criteria air contaminants

• produced mostly by combustion engines
• smelly red-brown gas: contributes to smog and acid precipitation

Question 10

particular matter (PM) falls under which category of air pollutants?
- produced how?

Answer 10

criteria air contaminants
- tiny solid or liquid particles
- produced by combustion & dust

Question 11

Volatile Organic Compounds (VOCs) falls under which category of air pollutants?
- produced how?
- what is it?

Answer 11

criteria air contaminants
- C compounds that are volatile
- household chemicals, engine combustion, solvents, industrial processes

eg. methane, propane, butane

Question 12

carbon monoxide (CO) falls under which category of air pollutants?
- produced how?
- what is it?

Answer 12

criteria air contaminants
- colorless, odorless gas (dangerous)
- combustion of fuel, waste, wood

Question 13

ammonia (NH3) falls under which category of air pollutants?
- what is it?
- produced how?

Answer 13

criteria air contaminants
colorless gas, smells like urine
- produced by livestock waste, fertilizer production

• can combine with sulfates and nitrates to create PM2.5 (secondary PM)

Question 14

tropospheric ozone falls under which category of air pollutants?
- what is it?
- how is it produced?

Answer 14

criteria air contaminants
- colorless gas
- secondary pollutant, created from the interaction b/w sunlight, heat, NOx, and C compounds

Question 15

the good ozone is in the _____
ozone is a pollutant when it is in the _____

Answer 15

stratosphere= good
troposphere= bad

Question 16

POPs primarily come from ___ sources

Answer 16

anthropogenic

Question 17

Human exposure to POPs is mainly through ___
EXCEPT:
____

Answer 17

food

chlordane
- used against insects on crops (50s and 60s)
- now banned, but we’re still being exposed to it b/c it’s persistent (via the fields it was sprayed on)

Question 18

what are the 2 heavy metals of concern?
3 problems with them?

Answer 18

lead and mercury

Problems:
1. associated with particulate matter, easily transported in the atmosphere
2. toxic, even in low [ ]
3. can bioaccumulate

Question 19

give 3 examples of toxic air pollutants (other stuff that doesn’t fit into the other categories)

Answer 19

• asbestos (in insulation, fire retardant)
• CFCs (refrigerants, solvents)
• methyl bromide (used in soil & shipped materials to control pests)

Question 20

smog=

Answer 20

mixture of air pollutants that form primarily over urban areas
(typically not harmful on their own, but they are when they mix)

Question 21

industrial smog=

Answer 21

produced from the incomplete combustion of coal or oil
grey
- can cause acid rain

Question 22

photochemical smog=

Answer 22

produced from light-driven reactions b/w pollutants and atmospheric components
- brown
- NO2 involved in secondary reactions to create more pollutants

Question 23

Canada’s air quality health index is calculated based on relative risks of which 3 common air pollutants?

Answer 23

• tropospheric ozone
• particulate matter
• NO2

Question 24

outdoor air pollution affects non-humans. give 2 examples

Answer 24

• acid rain (inc acidity of water and soil)
• high levels of mercury in birds near power plants (inhalation)

Question 25

what are the 3 main atmospheric cells?

Answer 25

• Polar cell (poles)
• Ferrel cell (middle)
• Hadley cell (equator)

Question 26

cold air is ___(heavier/ lighter) and ____(descends/ rises)

warm air is __ and ___ and absorbs more __ (forms clouds)

Answer 26

cold: heavier, descends

warm: lighter, rises, absorbs water

Question 27

where do secondary pollutants form?

Answer 27

in the free troposphere, above the boundary layer (~1km)

Question 28

thermal inversion caused the terrible smog in Beijing. Explain how a terminal inversion works

Answer 28

cold air= stagnated close to the ground, trapped by warm air above

Normal situation:
Cold air
Cool air
Hot air

Thermal Inversion:
Cold air
Inversion layer (warmer air)
Cold air- trapped with no convection (inc pollution)

Question 29

fog in the river valley is an example of a

Answer 29

localized thermal inversion

Question 30

when a thermal inversion ends, what happens?

Answer 30

the stagnated air moves somewhere else (including the pollution)

the Beijing pollution moved to western north america!

Question 31

T/F
air pollution can change the weather
give example

Answer 31

true

eg. in asia: pollution has worsened winter cyclones b/c of more aerosols in the air)