10 gaseous pollutants I

Question 1

what are we going to discuss in lectures 10 and 11?

Answer 1

-status or air pollution on human health (impact of air pollution)
-major types of air pollutants
-primary air pollutants: sources and toxicity
-secondary air pollutants: sources, environmental processes, toxicity
-air quality regulations

Question 2

what are the health consequences of air pollution in canada?

Answer 2

according to health canada report released in 2021, air pollution:
-causes 15,400 premature deaths per year
-10,000 deaths due to chronic PM2.5 exposure (8% of all nonaccidental death of people >25 yrs)
-1,300 deaths due to acute NO2 exposure
-2,800 deaths due to acute O3 exposure

-economic cost of hospitalization, emergency room and doctor’s office visits: 114 billion CAD in 2016

Question 3

what are major types of air pollutants?

Answer 3

-gaseous
-particulates
-droplets or mist
-smog

-CO2 isnt characterized as an air pollutant

Question 4

what is the gaseous type of air pollutants?

Answer 4

-inorganic (e.g. SO2, NOx species, CO, O3)
-volatile organic compounds or VOCs (e.g. hydrocarbons, halogenated compounds)

Question 5

what is the particulate type of air pollutants?

Answer 5

-particles (0.01-100 um in diameter)
-other gases and liquids will absorbed to particulates

Question 6

what is the droplets or mist type of air pollutants?

Answer 6

-small liquid droplets (1.0-2.0 um) will remain suspended in air
-other gases or liquids will dissolved in droplets

Question 7

what is the smog type of air pollutants?

Answer 7

-combination of smoke and fog (gases and particulates)
-brown or yellow haze in big cities

Question 8

what are some important physical processes in air pollution?

Answer 8

-volatilization
-advection
-deposition
cold precipitation

Question 9

what is volatilization?

Answer 9

-from water, soil and other surfaces or produced directly
-may adhere/dissolved into particulate/droplet

Question 10

what is advection?

Answer 10

-vapor, particulates or droplets quickly borne away by air currents
-transported great distances if carried into higher atmosphere

Question 11

what is deposition?

Answer 11

dry
-particulate settling on land/water due to gravitational pull
-most particulates are charged -aggregation
-likely greater contributor than wet, even in damp conditions

wet
-dissolved pollutant carried to earth via liquid droplets (e.g. rain or dew)

Question 12

what is cold precipitation?

Answer 12

-vapour form of volatile pollutant precipitates as liquid/solid (in absence of water or particulate) and falls to earth because of colder temperatures
-occurs mainly at higher latitude, and/or higher altitude

Question 13

what are the two categories (types) of air pollutants?

Answer 13

-primary air pollutants: harmful chemicals that enter directly into the atmosphere
-secondary air pollutants: harmful chemicals that result from chemical interactions of primary pollutant or primary pollutants reacting with other compounds normally found in atmosphere

Question 14

what is sulfur dioxide? what are the sources and toxicity?

Answer 14

sulfur dioxide (SO2) is a primary air pollutant
-anthropogenic source: combustion of fossil fuels, smelting of mineral ores

toxicity
-plants: affects photosynthesis, transpiration, and respiration
-humans: chronic lung diseases such as broncho-constriction, pulmonary edema

Question 15

what are nitrogen oxides? sources? toxicity?

Answer 15

NO, NO2 which are primary air pollutants
-they are oxidizing (can oxygen hemoglobin which means it can not longer carry oxygen)
-anthropogenic source: combustion of fossil fuels (petroleum from cars)

toxic effects
-plants: inhibition of photosynthesis and lipid biosynthesis
-humans: irritation of lungs, lowered hemoglobin, depressed immune functions

Question 16

what is carbon monoxide?

Answer 16

CO, primary air pollutant (way more toxic that CO2)
anthropogenic sources:
-combustion of carbonaceous materials including hydrocarbons
-can remain in the atmosphere up to 1 month before being oxidized to CO2

Question 17

is the level of carbon monoxide going up or down?

Answer 17

Question 18

what are the toxic effects of carbon monoxide?

Answer 18

-hypoxia -tightly bind to hemoglobin (with 200x greater affinity than oxygen)
-critical tissue damage (e.g. brain)/death
-immune and cardiovascular impairment
-neonatal effects: reduced birth weight

Question 19

what is the graph of the symptoms/effects of CO exposure on humans?

Answer 19

doesn’t necessarily health to put person in oxygen chamber, because CO binds so tight to Hb

Question 20

what are the CO exposure limits in canada?

Answer 20

Question 21

what are VOCs (primary air pollutant)?

Answer 21

volatile organic carbons

anthropogenic source:
-carbon-containing gases and vapors (including PAHs) such as gasoline fumes and solvent (but excluding carbon dioxide, carbon monoxide, and chlorofluorocarbons)

toxic effects: humans
-carcinogenicity (especially PAHs)
-neurotoxicity

Question 22

what did the discover about PAHs?

Answer 22

leads to indoor exposure through inhalation and dermal
-remove 50% in washing machine

Question 23

what are the types of particulate matter (primary air pollutant)?

Answer 23

-coarse particulates (PM10)
-fine particulates (PM2.5)
-ultrafine particulates (PM0.1)

Question 24

what are coarse particulates?

Answer 24

10 microns
-pollen, sea salt and particles from man-made products (e.g. tires, concrete)
-metal oxides of silicon, aluminum, calcium and iron
-coarse particulates precipitate quicker (dont stay suspended in the air for long periods of time)
-dont penetrate as deep into lungs

Question 25

what are fine particulates?

Answer 25

2.5 microns -carbonaceous materials, sulfates, ammonium, and nitrates -trace metal compounds (Ni, Pb, Zn, Cu and Al) -small particulates are charged, but also bind to lipophilic compound

Question 26

what are ultrafine particles?

Answer 26

0.1 microns -same composition as PM2.5

Question 27

how small is particulate matter compared to human hair?

Answer 27

Question 28

what are the sources of PM<10 and PM<2.5 in canada?

Answer 28

Question 29

what is the global annual PM<2.5 concentration change from 2001 to 2010?

Answer 29

Question 30

what are the concentrations of PM2.5 in cities around the world?

Answer 30

Question 31

why is the annual PM2.5 average concentration misleading?

Answer 31

some days have levels that are way above safe levels

Question 32

what is the pie chart on air quality?

Answer 32

pie chart showing total global exposure to particulate matter air pollution -very large footprint for indoor because biomass fuels (wood, coal)

Question 33

what is the graph of the lungs?

Answer 33

-alveoli are very sensitive and delicate -alveoli is site of gas exchange -alveoli has only one layer of epithelial cells

Question 34

what is the graph of uptake by ultrafine particles in mice lung?

Answer 34

red=distribution of particles in lung

Question 35

what is the mode of toxic action of fine particulates?

Answer 35

inflammation (inflammatory response): triggered by cell injury or pathogens (recruits white blood cells) can have adverse effects -sustained activation of immune response leads to chronic inflammation (level of white blood cells will go up and it is more common is big cities) -more white blood cells=more oxidative stress

Question 36

what are the toxic effects in humans of particulate matters?

Answer 36

-fine particles retained in lungs -lung and systemic inflammation -chronic bronchitis, COPD (air tubes become more stiff due to swelling and results in less air flow to lungs) -induce acute cardiovascular events (fine and ultra are major source of lung cancer)