7.1: Introduction to Air Pollution

What are the six criteria air pollutants identified by the Clean Air Act?

Nitrogen Oxides (NOx), Carbon Monoxide (CO), Sulfur Dioxide (SO2), Ozone (O3), Particulate Matter (PM), and Lead (Pb).

What is the primary source of sulfur dioxide (SO2) emissions?

Coal combustion.

What health impacts are associated with sulfur dioxide (SO2)?

It is a respiratory irritant that can worsen asthma and bronchitis.

What is particulate matter (PM)?

A mixture of tiny solid particles and liquid droplets in the air that can cause respiratory issues.

What is the difference between primary and secondary air pollutants?

Primary pollutants are emitted directly from sources, while secondary pollutants form in the atmosphere through chemical reactions.

What is residence time in the context of air pollutants?

The time a pollutant stays in the atmosphere, affecting its localized or regional/global impact.

What is the environmental impact of nitrogen oxides (NOx)?

They are respiratory irritants and contribute to the formation of tropospheric ozone and acid precipitation.

What was the role of the EPA regarding lead in gasoline?

The EPA began phasing out lead from gasoline in 1974 due to its neurotoxic effects.

How does carbon dioxide (CO2) differ from the six criteria pollutants?

CO2 is not considered a criteria pollutant as it does not directly lower air quality or cause smog.

What is the significance of the 2007 Supreme Court ruling regarding greenhouse gases?

It allowed the EPA to regulate greenhouse gases, including CO2.

What are the sources of nitrogen oxides (NOx)?

Combustion of fossil fuels and biomass.

What is the impact of coal combustion on air pollution?

It releases a significant amount of pollutants including CO, CO2, SO2, NOx, toxic metals, and PM.

What is photochemical smog and what causes it?

A type of air pollution formed by the reaction of sunlight with pollutants like NOx and volatile organic compounds (VOCs).

What are the health effects of ozone (O3) at the tropospheric level?

It can cause respiratory issues and is harmful to human health.

What is the role of sunlight in the formation of secondary pollutants?

Sunlight drives the chemical reactions that convert primary pollutants into secondary pollutants.

What is the primary pollutant that can transform into nitric acid?

Nitrogen oxides (NOx) combine with water and oxygen in the atmosphere to form nitric acid.

What are the environmental consequences of acid precipitation?

It can harm aquatic ecosystems, damage forests, and degrade soil quality.

What is the relationship between incomplete combustion and air pollutants?

Incomplete combustion can produce harmful pollutants like carbon monoxide and particulate matter.

What is the significance of catalytic converters in vehicles?

They reduce emissions of NOx, CO, and hydrocarbons, helping to mitigate air pollution.

How does coal combustion affect visibility and photosynthesis?

Sulfur aerosols from coal combustion block sunlight, reducing visibility and photosynthesis.

What are the primary sources of particulate matter (PM) in the air?

Combustion of fossil fuels, biomass, and industrial processes.