Responses of natural wildlife populations to air pollution.

Deer mice (Peromyscus californicus) trapped in areas of Los Angeles with high ambient air pollution are significantly more resistant to ozone (6.6 ppm for 12 h) than are mice trapped from areas with low ambient pollution (56 versus 0% survival, respectively). Laboratory-born progeny of these mice show similar response patterns, indicating a genetic basis to this resistance. Young mice (less than 1 yr of age) are more sensitive than older mice (15 versus 44% survival, respectively). Sensitivity is also affected by degree of inbreeding; progeny of full-sib crosses are more sensitive than randomly bred deer mice. The data suggest that deer mice are more resistant to ozone toxicity than are commercially bred laboratory mice and rats.