If you will be staying in Los Angeles for more than a day or two, keep an eye on city smog alerts, and take adequate precautions. The Los Angeles basin structure traps air pollution, which maintains an unhealthy air quality often during the year. Certain weather conditions or geophysical events—like a wildfire, for example—can make matters worse. Some sections of the city have it worse than others, especially the valleys, where poor air can get wedged in pretty securely, adding to the usual misery suffered by those with congestive heart failure, respiratory problems, or allergies to airborne substances. Check the smog alerts before going outdoors, and wear a nose mask, if warranted.  « piilota

No matter that Los Angeles is an urban center with massive skyscrapers and ultramodern conveniences. Keep in mind that the desert is not that far away, and the summer temperatures can quickly blister unprotected human skin. Despite the fresh air breezes off the ocean, remember to take along your sunscreen and sunglasses. It’s also a good idea to dress in light-colored clothing made of lightweight fabric. Pavements can become very hot, too, so be careful about letting the kids go barefoot on sidewalks and streets. Even foggy or smoggy areas can let in enough sunrays to damage your skin, so be prepared for the outdoors.  « piilota