1.2 Photochemical smog Flashcards
What conditions are necessary for photochemical smog?
- Bright sunlight
- High temperature
- High concentration of pollutants
- Temperature inversion
- Still air mass
What is a primary pollutant?
A pollutant EMITTED into the atmosphere due to human activities.
What is a secondary pollutant?
A pollutant FORMED in the atmosphere by reactions of primary pollutants that are initiated by photons.
What are the reactions that lead to the formation of nitrogen oxides?
High temperatures which are provided, break the bonds of the polar nitrogen and oxygen molecules, initiating a reaction. Forming nitric oxide.
N2. +. O2 –> 2NO
Nitric oxide further reacts in the atmosphere to form nitrogen dioxide.
2NO + O2 –> 2NO2
How does ozone form in the atmosphere, with the contribution of nitrogen oxides?
High temperatures break the polar bonds in the nitrogen and oxygen molecules, initiating a reaction. Forming nitric oxide.
N2. +. O2 –> 2NO
Nitric oxide further reacts in the atmosphere to form nitrogen dioxide.
2NO + O2 –> 2NO2
In the presences of sunlight (UV), nitrogen dioxide photochemically dissociates, forming nitric oxide and oxygen radical (highly reactive).
NO2 + sunlight –> NO + O
Oxygen radical reacts with atmospheric oxygen, forming ozone.
O + O2 –> O3
How does ozone and nitrogen oxides effect humans and animals?
Damage on the lungs and heart, irritation to the respiratory system, asthma attacks and eye irritation.
How does ozone and nitrogen oxides effect the environment?
Interfere with growth and productivity of trees, ozone undergoes reactions in plant cells and disrupts photosynthesis. Makes them more susceptible to disease.
What is the purpose of a catalytic converter?
reduces emissions of hydrocarbons and nitric oxide, thereby limiting smog at its source.
What is the structure of a catalytic converter?
honeycomb structure, made out of platinum with a large surface area.
equation for the production of carbon monoxide in internal combustion engines.
C8H18 (g) + 8½O2(g) → 8CO (g) + 9H2O (l)
equation for the removal of carbon monoxide and nitric oxide in internal combustion engines.
2CO(g) + 2NO(g) → N2(g) + 2CO2(g)
