Glad you enjoyed them!

There are probably more bikes than cars, but there are still a lot of cars -- the city's population is about 15 million, and the traffic jams are unbelievable. The real problems in addition to cars (you get really smoky trucks, too) are coal-fired powerplants, some industries, dust thrown up from construction sites (especially in the massive construction run-up to the Olympics), and the city's location near expanding deserts to the north-west. The construction dust is probably an even bigger problem here than in most other places, since the soil is so dry. We had no rain, and only about 4 inches of total snow between November and late March.