求翻译：中国大城市交通所面临的第二个突出问题，就是机动车迅速增长所带来环境污染。目前，机动车污染已经上升为中国城市大气和噪声的主要污染源。是什么意思？

Chinese cities are facing traffic the second outstanding issue is the rapid growth of motor vehicles caused by environmental pollution. Currently, motor vehicle pollution has risen in China's major urban air and noise pollution.

China's largest city traffic, as the first two prominent issues facing the rapid growth of motor vehicles, and that is the environmental pollution. At present, China has been elevated to motor vehicle pollution and noise of urban atmospheric major sources of pollution.

The China big municipal transportation faces the second prominent question, is the vehicle rapid growth brings the environmental pollution.At present, the vehicle pollution already rose for the Chinese city atmosphere and the noise main source of pollution.

China's outstanding problems of urban transport in the second, was brought about by the rapid growth in motor vehicle pollution. Currently, vehicle pollution has increased mainly on Chinese urban atmospheric and noise pollution.

China's outstanding problems of urban transport in the second, was brought about by the rapid growth in motor vehicle pollution. Currently, vehicle pollution has increased mainly on Chinese urban atmospheric and noise pollution.