It sounds to me like: "Now we've no cold front yet to help disperse it. A dense smog is said to hang over..." (and he goes on to list the cities and says it will last another week). The problem is that he runs the two sentences together instead of making a good break between "it" and "A".

"The national weather center and environment ministry have issued a joined forecast on the continuous pollution here. Now with no cold front yet to help disperse it, dense smog is set to hang over Beijing, and (various Chinese cities) for a week. Locals have been advised to take protective measures and encouraged to use public transport over their cars."

The following is the diction of the whole video clip I write after adopting your answer. I think there are still some problems in the very first part.:( ...The heavy smog are smothering the northern part. The national weather center and the environment ministry have issued a joint forecast on the continuous pollution here. Now with no cold front yet to help disperse it, dense smog is said to hang over BJ& TJ, as well as HB& SD for another week. Locals have been adviced to take protective measures and encouraged to choose public transport over their cars. Children and also the elderly are being asked to stay indoors. Kingergardens, primary and middle schools could still suspend their classes.