Photochemical Smog and Thermal Inversions

These flashcards cover key concepts related to photochemical smog and thermal inversions, their causes, consequences, and effects on health and the environment.

What causes photochemical smog?

Photochemical smog is caused by the action of solar UV light on the atmosphere polluted with hydrocarbons and nitrogen oxides.

What are the main products of photochemical smog?

The main products are ozone (O3) and peroxyacyl nitrates (PANs).

What are primary pollutants?

Primary pollutants are substances directly emitted into the air, such as nitrogen oxides and volatile organic compounds.

What are volatile organic compounds (VOCs)?

VOCs are organic (hydrocarbon) chemicals that vaporize into gas and can range from harmless to toxic.

When is photochemical smog most likely to be seen?

Photochemical smog is most likely to be seen in urban areas during rush hour, in the afternoon, and in the summer.

What are the two types of ozone?

Tropospheric ozone (the 'bad' ozone created by anthropogenic activity) and stratospheric ozone (the 'good' ozone that protects us from UV radiation).

What health effects are associated with photochemical smog exposure?

Health effects include irritation of eyes, nose and throat, worsening of respiratory conditions, and potential cancer risk.

What is a thermal inversion?

A thermal inversion occurs when a layer of hot air traps denser, cooler air at the surface, altering the normal temperature gradient.

What environmental conditions can increase the likelihood of thermal inversions?

Windless weather conditions, nighttime, winter, and geographical features like valleys and mountain ranges can increase the likelihood of thermal inversions.

What was the case study example of a thermal inversion's impact?

In Tianjin, China in 1998, a thermal inversion trapped pollutants leading to carbon monoxide poisoning and deaths among the population.