Air Pollution Quiz 3

Front 1

coagulation

Back 1

collision and coalescence of 2 particles (reduce #, conserve volume)

Front 2

Condensation/evaporation

Back 2

gas condenses (changes to liquid) onto particle surface,
evaporation of liquid from particle to gas (affects volume & area, not #)

Front 3

dissolution

Back 3

gas dissolves into water that is already on the particle surface (affects volume, not
#)

Front 4

dissociation

Back 4

once dissolved or condensed onto particle, break into ions within particle (no effect on #) example is sea-spray acidification

Front 5

sea-spray acidification

Back 5

HNO3 + CL- = HCl + NO3-.

H2SO4 or HNO3 enter sea-spray drops, which contain NaCl, and then dissociate

Cl- (NaCl) displaced by NO3- (or SO42-) to give HCl gas

After all Cl- is depleted, get a build up of H+ from HNO3 (or H2SO4), which decreases pH
and increases acidity (HNO3 and H2SO4 are stronger acids than HCl)

Worst by coastal regions near pollution sources, where there is abundant H2SO4 and
HNO3

Front 6

soil-particle acidification

Back 6

CaCO3 + 2HNO3 = Ca2+ + NO3- + CO2 + H2O

NO3 dissolves onto soil particles that contain CaCO3 or MgCO3 and dissociate

CO32- displaced by NO3- to make CO2 gas

After all CO32- is depleted, get a build up of H+ from HNO3, which decreases pH and
increases acidity

Front 7

Dry Adiabatic Lapse Rate

Back 7

negative change in temp with height for dry air, 10°C/km

Front 8

stability

Back 8

whether an air parcel will rise or not, i.e., whether pollution will mix vertically or be trapped near the surface

Front 9

Do pollutants disperse better when the air is stable or unstable?

Back 9

unstable

If parcel is warmer than Γe then it is unstable b/c will keep rising

If parcel is cooler than Γe then it is stable b/c will sink (more dense)

Parcel will rise at Γd until Tparcel = Te (become same temp as surrounding/environmental air)

Front 10

If a parcel of air pollution is dry and is emitted at the ground, at what rate would the air parcel rise if it could?

Back 10

adiabatic

Front 11

What determines when a particle stops rising or if it rises at all?

Back 11

temperature of the environment, esp temperature inversions

Front 12

Define temperature inversion

Back 12

temperature increase with height

Stronger inversion has greater temp difference between cooler surface and warmer air above

Why are temperature inversions important in air pollution?
-trap pollutants near the surface,
concentrations build up

Front 13

large scale subsidence

Back 13

occurs within a surface high pressure system (sinking, compressing, warming air over cooler surface)

Front 14

Radiation inversion

Back 14

nighttime cooling of ground and air molecules above the ground (with warmer air further up)

Front 15

Marine Inversion

Back 15

from sea breeze (get cool air from water at surface and warmer air from land in upper branch)

Front 16

Regional (small-scale) subsidence inversion

Back 16

air compresses and warms as it moves down a mountain slope, flows above cooler air from water

Front 17

Frontal inversion

Back 17

cold air from leading edge of cold front wedges under leading edge of warm air mass (warm air mass rises above cold air mass)

Front 18

Plume: Fanning

Back 18

stable throughout

Front 19

Plume: Fumigating

Back 19

stable above, neutral/unstable below

Front 20

Plume: Looping

Back 20

unstable throughout

Front 21

Plume: Lofting

Back 21

neutral above, stable below

Front 22

Plume: Coning

Back 22

neutral throughout

Front 23

absorption

Back 23

light entering particle, increasing the internal energy of the particle

Removes that wavelength

Front 24

scattering

Back 24

light getting redirected by particle, with no change in energy

We see these wavelengths

Front 25

Why is the sky blue during the day?

Back 25

air molecules preferentially and repeatedly scatter blue (short) wavelengths out of the direct beam to the viewers’ eyes

Front 26

Why is the horizon red at sunset and sunrise?

Back 26

all colors are scattered and re-scattered by aerosol particles along the horizon, then B and G wavelengths are repeatedly scattered away from the line of sight by gas molecules, so that we only see the R that is transmitted to the eyes

Front 27

Do gases or particles cause most of the visibility loss in an urban area? Why?

Back 27

Particles

particles scatter and absorb more light than gases

All particles scatter light and more particles absorb light than gases

Only NO2, O3 and NO3 gases absorb visible light and gas scattering has a very small effect
on visibility (O2 and N2 are most important, affect colors or sky and sun)

Front 28

which processes reduce visibility the most?

Back 28

Particle scattering > particle absorption > gas absorption > gas scattering

Front 29

White clouds

Back 29

water particles scatter R, G, B (all wavelengths scattered equally), so get white

Front 30

Brown smog

Back 30

R with some G gives brown – NO2, PAH’s, and soil dust absorb B and some G,
transmit R and some G to give brown

Front 31

Black smoke

Back 31

mainly black carbon (component of soot), absorbs all wavelengths (appear black)

Front 32

Purple stratosphere

Back 32

sulfuric acid-water particles (from volcanoes) scatter light through
stratospheric ozone layer, and ozone absorbs G and some R to give purple (B and some R)