Why Are Photochemical Smog Levels Higher Than Predicted In Los Angeles?
CHEMISTRY – SECTION D
Vocabulary
Pollutants
An undesirable contaminant that adversely affects the chemical, physical, or biological characteristic of the environment
Primary air pollutants
A contaminant that directly enters the atmosphere; it is not initially formed by reactions of airborne substances
Secondary air pollutants
A contaminant generated in the atmosphere by chemical reactions between primary air pollutant and natural components of air
Particulate pollutants
Microscopic particle that enters the air from either human activities or natural process
Volatile organic compounds (VOCs)
Reactive carbon-containing substances that readily evaporates into air, such as components of gasoline and organic solvents
Criteria …show more content…
(temperature inversion)
In LA, the combination of sunny weather and mountains can produce temperature inversion about 320 days annually. During a temperature inversion, air pollutants cannot escape, so their concentration may rise to dangerous levels. The production and severity of photochemical smog, which can occur even without a temperature inversion, are amplified by that accumulation of pollutants. The reason of this is because the mountain gets the cool air beneath a less dense warm air mass.
Know how photochemical smog is produced
Hydrocarbons, carbon monoxide from vehicle exhausts are irradiated by sunlight in the presence of oxygen gas. The resulting reactions produce a potentially dangerous mixture, including other nitrogen oxides, ozone, and irritating organic compounds, as well as carbon dioxide and water vapor.
Hydrocarbons + sunlight + O2 + CO + NOx →O3 + NOx + organics + CO2 + H2O
Explain why photochemical smog formation varies throughout the day
Early morning traffic increases the emissions of both nitrogen oxides and VOCs as people drive to work.
Later in the morning, traffic dies down and the nitrogen oxides and volatile organic compounds begin to be react forming nitrogen dioxide, increasing its …show more content…
(chemical reactions of CO2, SOx, and NOx with water)
Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain
Precipitation with a pH less than 5.6
Write the reactions of CO2, SO2, and NO2 with water
CO2 in water: CO2 + H2O H2CO3
SOX in water: SO2 + H2O H2SO3
NOX in water: 2 NO2 + H2O HNO3 (nitric acid) + HNO2 (nitrous acid)
Explain how carbon dioxide, sulfur oxides, and nitrogen oxides enter the atmosphere
Carbon dioxie living beings, industries, automobiles, burning of fossil fuels
Sulfur oxides burning coal (power plants +
Vocabulary
Pollutants
An undesirable contaminant that adversely affects the chemical, physical, or biological characteristic of the environment
Primary air pollutants
A contaminant that directly enters the atmosphere; it is not initially formed by reactions of airborne substances
Secondary air pollutants
A contaminant generated in the atmosphere by chemical reactions between primary air pollutant and natural components of air
Particulate pollutants
Microscopic particle that enters the air from either human activities or natural process
Volatile organic compounds (VOCs)
Reactive carbon-containing substances that readily evaporates into air, such as components of gasoline and organic solvents
Criteria …show more content…
(temperature inversion)
In LA, the combination of sunny weather and mountains can produce temperature inversion about 320 days annually. During a temperature inversion, air pollutants cannot escape, so their concentration may rise to dangerous levels. The production and severity of photochemical smog, which can occur even without a temperature inversion, are amplified by that accumulation of pollutants. The reason of this is because the mountain gets the cool air beneath a less dense warm air mass.
Know how photochemical smog is produced
Hydrocarbons, carbon monoxide from vehicle exhausts are irradiated by sunlight in the presence of oxygen gas. The resulting reactions produce a potentially dangerous mixture, including other nitrogen oxides, ozone, and irritating organic compounds, as well as carbon dioxide and water vapor.
Hydrocarbons + sunlight + O2 + CO + NOx →O3 + NOx + organics + CO2 + H2O
Explain why photochemical smog formation varies throughout the day
Early morning traffic increases the emissions of both nitrogen oxides and VOCs as people drive to work.
Later in the morning, traffic dies down and the nitrogen oxides and volatile organic compounds begin to be react forming nitrogen dioxide, increasing its …show more content…
(chemical reactions of CO2, SOx, and NOx with water)
Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain
Precipitation with a pH less than 5.6
Write the reactions of CO2, SO2, and NO2 with water
CO2 in water: CO2 + H2O H2CO3
SOX in water: SO2 + H2O H2SO3
NOX in water: 2 NO2 + H2O HNO3 (nitric acid) + HNO2 (nitrous acid)
Explain how carbon dioxide, sulfur oxides, and nitrogen oxides enter the atmosphere
Carbon dioxie living beings, industries, automobiles, burning of fossil fuels
Sulfur oxides burning coal (power plants +