Chemistry · Ch 15 — Environmental Chemistry
Atmospheric Pollution
Atmospheric Pollution
Earth's atmosphere is a layer of gases held in place by earth's gravity. By volume it is roughly 78% nitrogen, 21% oxygen, 0.93% argon, 0.04% carbon dioxide, with trace amounts of other gases and a little water vapour -- this whole mixture is what we commonly call air.
The atmosphere is not uniform with altitude: it divides into distinct layers, each with a characteristic altitude range, temperature range, and dominant gases/species, summarised below.
| Region | Altitude from earth's surface | Temperature range | Gases/species present |
|---|---|---|---|
| Troposphere | 0-10 km | 15°C to -56°C | N₂, O₂, CO₂, H₂O (vap) |
| Stratosphere (ozonosphere) | 10-50 km | -56°C to -2°C | N₂, O₂, O₃, O atoms |
| Mesosphere | 50-85 km | -2°C to -92°C | N₂, O₂⁺, NO⁺ |
| Thermosphere | 85-500 km | -92°C to 1200°C | O₂⁺, O⁺, NO⁺, e⁻ |
| Region | Altitude from earth's surface | Temperature range | Gases/species present |
|---|---|---|---|
| Troposphere | 0-10 km | 15°C to -56°C | N₂, O₂, CO₂, H₂O (vap) |
| Stratosphere (ozonosphere) | 10-50 km | -56°C to -2°C | N₂, O₂, O₃, O atoms |
| Mesosphere | 50-85 km | -2°C to -92°C | N₂, O₂⁺, NO⁺ |
Troposphere
The troposphere is the lowest layer of the atmosphere, extending from earth's surface up to about 10 km, and it holds roughly 80% of the total mass of the atmosphere. It is the layer in which humans, animals and plants actually live and breathe, so pollution here has the most direct impact on life. The textbook further divides the troposphere's living space into three overlapping 'spheres', covered in the next thre …