exam 3: air pollution part 1

Distinguish between natural and anthropogenic pollution sources.

Natural: comes from nature like volcanoes and wildfires; anthropogenic pollution: caused by humans like cars factories and burning fuel

Review Table 8.5 in your text. What are the seven pollutants that are regulated by the NAAQS?

CO (carbon monoxide), Pb (lead), NO2 (nitrogen dioxide), O3 (ozone), PM (smoke), SO2 (sulfur dioxide)

What is the difference between a primary standard and a secondary standard?

Primary: protects human health; secondary: protects environment and property

Review the 4 strokes in an Otto internal combustion engine (ICE). Based on the chemical formula for combustion, ideally what two gases should only be released from the combustion of gasoline?

Intake, compression, power, exhaust; CO2 and H2O

What is knocking? Explain what happens in an engine that results in knocking. In particular, between what two strokes in an Otto engine does it occur?

Fuel explodes too early between compression and power strokes; causing noise, damage, and less efficiency

What is TEL? Why did the petroleum companies promote TEL instead of ethanol as the primary additive to reduce knocking in gasoline?

It is lead and it is added to stop the knowing; they chose this because it made more money

Describe the health risks of lead from acute in adults and low-level exposure in children.

Adults: headaches, memory loss; children: brain damage and learning problems

Describe how the Kehoe Paradigm was used to ensure companies could continue to put lead in gasoline even though medical and scientific evidence showed that Americans were silently being poisoned by lead. How does this paradigm exploit the scientific method to achieve its results? Remember, the goal is not to win the argument, it is to __________ the argument.

They claimed lead was safe unless proven harmful by the consumers; it delayed action by demanding perfect proof; the goal is to delay the argument not win it

• What are VOCs? List the two ways VOC are released into the environment when using an ICE.

Chemicals that became a gas; 1 fuel evaporation 2 incomplete fuel burning

Review Figure 6.12 in your text. The rubber bellows on a gasoline nozzle is used to reduce what type of pollution.

Reduces VOC pollution from fuel vapors

Describe how NOx forms in an internal combustion engine.

High engine heat makes nitrogen (N2) and oxygen (O2) combine

Explain the negative health effects of exposure to NOx.

Lung problems, asthma, heart stress

Describe the formation of Photochemical smog. o Using simple chemical formulas, show how ozone, NO2, NO, and O2 are kept in equilibrium in the absence of VOCs. o Describe how VOCs disrupt this equilibrium and lead to the formation of oxidants and Photochemical Smog.

NO2  → NO + O (sunlight)    O + O2  → O3    O3 + NO  → NO2 (keeps balance); with VOCs: VOCs trap NO, more O3 builds up  → smog and harmful oxidants

 Review figure 6.11 in your text. What time of day and what time of year are ozone levels the highest? Why?

Noon and summer; more sunlight and heat make more ozone

What devices can be used to reduce the amount of CO and VOCs emissions? Explain how these measures increase NOx emissions.

Catalytic converters because they increase NOx because higher temps are needed to burn off CO and VOCs

What three pollutants does a catalytic converter remove?

CO, VOCs (hydrocarbons), and NOx

Explain why leaded gasoline was phased out in the United States beginning in the early 1970s. Was this based on the fact the lead was a poisonous substance?

Lead is poisonous, especially to kids but it also damages catalytic converters