Photochemical Smog

Question 0

Turbulent convective mixing

Answer 0

Prevented, gases emitted trapped

Question 1

LA basin?

Answer 1

Mountain on 3 sides , wind off sea, closed reaction vessel with lid, frequent temperature inversions, warm air overlying cold air at ground level

Question 2

What are the reactants?

Answer 2

Motor vehicle - exhaust gases and sunlight (long hours in LA)

Question 3

What accumulates?

Answer 3

Brown haze fumes containing ozone and other photochemical oxidants

Question 4

HCs concentration

Answer 4

Peaks early morning rush hour

Question 5

NO

Answer 5

Concentration high in morning but declines on conversion to NO2

Question 6

Oxidants levels?

Answer 6

Concentration rises as HC levels fall

Question 7

Formation of photochemical Smog

Answer 7

Oxygen + energy from stratosphere by UV light absorption

Question 8

What happens at ground level?

Answer 8

UV level very low, critical ingredient NO2 (absorbs visible light), lander max at 400nm (blue region)

Question 9

Properties of photo excited NO2

Answer 9

Unstable, decomposes

Question 10

Below 400nm

Answer 10

Does not decompose

Question 11

What leads to net ozone production?

Answer 11

HCs need to interfere, alternative route for NO to NO2 (does not consume ozone)