- Mountains: The San Gabriel Mountains to the north and east of Los Angeles, and the Santa Monica Mountains to the west, act as barriers that trap air pollution in the basin. This is because the mountains prevent the polluted air from dispersing and escaping.
- Ocean: The Pacific Ocean to the south of Los Angeles also contributes to the pollution problem. The ocean acts as a heat sink, which means that it absorbs heat from the sun and releases it slowly. This creates a temperature inversion, where the air near the ground is cooler than the air higher up. This inversion prevents the polluted air from rising and dispersing, and instead traps it near the ground.
- Climate: Los Angeles has a Mediterranean climate, with hot, dry summers and mild, wet winters. The hot summer temperatures also contribute to the pollution problem, as they cause the air to expand and rise, creating updrafts that carry pollutants higher into the atmosphere.
- Wind patterns: The wind patterns in Los Angeles are also a factor in the pollution problem. The prevailing winds in Los Angeles are from the west, which means that they carry pollutants from the ocean inland. These pollutants can then become trapped in the basin by the mountains and the temperature inversion.
- Urbanization: Los Angeles is a densely populated urban area, with over 10 million people living in the metropolitan area. This high population density means that there are a lot of sources of pollution, such as cars, factories, and power plants. The pollutants from these sources can all contribute to the pollution problem in Los Angeles.
All of these factors contribute to the pollution problem in Los Angeles, making the air quality in some parts of the city among the worst in the United States.
