Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.

### Instruction:
Explain the main cause of air pollution in the following city.

### Input:
Los Angeles

### Response:
The main cause of air pollution in Los Angeles is vehicle emissions. Los Angeles has a high number of automobiles and the exhaust emitted by these vehicles is a major contributor to the poor air quality in the city. Additionally, the large number of industrial facilities in the area also contributes to air pollution.