Despite the appeal of public transportation in the Chinese capital, private vehicles remain many residents' first choice for getting around.

"It's horribly crowded in the subway and hard to be on time when taking the bus," said Hu Yanrong, a 32-year-old consultant who drives 18 kilometers to her office every day. "We all know car exhaust contributes to the haze, but it's too exhausting to take a bus to work every day.

"No one wants to make the pollution worse, but you can't sacrifice your career either."