Air Quality and Atmospheric Pollution Control

Question 1

Primary pollutants

Answer 1

Emitted by identifiable sources

Question 2

Secondary pollutants

Answer 2

Formed in the atmosphere

Question 3

Criteria pollutants

Answer 3

identified to have negative impact on health of humans and the environment

Question 4

National Ambient Air Quality Standards (NAAQS)

Answer 4

outdoor criteria pollutant limits set by EPA

Question 5

Acid rain is caused by…

Answer 5

…sulfur dioxide reactions in the atmosphere creating sulfuric acid which is carried to the ground via rain

Question 6

Sulfur emissions can be reduced by…

Answer 6

… scrubbing emissions and removing sulfur from fuel (coal washing)

Question 7

Volatile organic compounds (VOCs)

Answer 7

high global warming and ozone depletion potential

Question 8

Ozone

Answer 8

blocks solar radiation in the upper atmosphere, but causes smog and irritation of mucus membranes in lower atmosphere

Question 9

Particulate matter

Answer 9

emitted primarily in urban areas through combustion processes

Question 10

Wind and weather patterns are a result of…

Answer 10

… the earth’s rotation and solar energy

Question 11

Atmospheric stability

Answer 11

the tendency of the atmosphere to resist vertical motion

Question 12

Atmospheres are classified as stable when…

Answer 12

… thermal effects restrict mechanical turbulence

Question 13

Atmospheres are classified as unstable when…

Answer 13

… thermal effects enhance mechanical turbulence

Question 14

Stability classifications are used to predict…

Answer 14

…the normal dispersion distance of contaminants as a function of distance downwind of a point source

Question 15

Cyclone

Answer 15

particle-laden gas is forced into a spiral motion- centrifugal forces causes higher density particles to contact the outer wall of the cyclone and fall out of gas flow into a collection tube

Question 16

Electrostatic precipitation

Answer 16

imparts negative charge on particles entering the unit which are then attracted to grounded collector plates

Question 17

Baghouse

Answer 17

Unit which holds several fabric tubes, air is directed inside to outside (shaker/reverse-flow system) or outside to inside (pulse-jet system)

Question 18

Air stripping

Answer 18

transfer of contaminant from liquid to gas phase

Question 19

Gas scrubbing

Answer 19

transfer of contaminants from gas phase to liquid phase

Question 20

Good adsorbents have…

Answer 20

… high specific surface areas, usually attributed to extremely porous internal structures

Question 21

Adsorption isotherm

Answer 21

describes a contaminant’s preference for the fluid or adsorbent phase

Question 22

Breakthrough

Answer 22

low concentrations of contaminant become present in packed bed effluent due to the majority of the column being saturated by adsorbate

Question 23

Breakthrough point

Answer 23

the time or volume at which the contaminant concentration in the effluent is 5% of the inlet concentration

Question 24

A column is considered exhausted when…

Answer 24

… effluent concentration of the contaminant is 95% of the inlet concentration