1) Regarding air pollution,
you might have mixed LA with SF.
LA is notorious of poor air quality because its locally unique basin-type climate, which prevent air from dispersing easily.
SF, dare to say, is quite different from LA.
The water quality in SF is sweet and good since majority of it is from Sierra mountain.
2) Earthquake should not be a big issue if your house is designed/constructed recently, when earthquake is well factored.
3) The house market in Bay area is in the middle of painful dipping session while the house price in Houston is flat forever:)
