AP Environmental Science: Thermal Inversions Notes
Thermal Inversions
- Definition: A thermal inversion occurs when a layer of warm air traps cooler air near the Earth's surface.
Urban Heat Island Effect
- Urban areas are often warmer than rural areas due to:
- Lower Albedo: Urban surfaces (like asphalt) absorb more sunlight.
- Evapo-transpiration: Less vegetation reduces cooling through water evaporation.
Normal Temperature Gradient
- Warm air is normally near the Earth's surface, cooling with altitude.
- This gradient helps to disperse air pollutants through convection.
- Can occur due to:
- Warm Fronts: A warm air mass moving over a colder one, common in coastal areas.
- Nighttime Cooling: Urban areas release stored heat at night, trapping warm air below cooler air.
Effects of Thermal Inversions
- Air Pollution Trapping: Pollutants are trapped near the ground, worsening air quality.
- Health Impacts: Increases in respiratory issues (e.g., asthma, COPD), leading to more hospital visits.
- Economic Costs: Health issues can incur costs; decreased tourism and lower productivity may occur.
- Decreased Photosynthesis: Dense smog reduces sunlight penetration, harming plants' ability to photosynthesize.