American golfer Jessica Korda shot a 5-under 68 on Friday to take a two-stroke lead after the second round of the Reignwood Classic in smog-shrouded Beijing.

Korda, who shared the first-round lead with Na Yeon Choi of South Korea, bogeyed the first hole before picking up the first of her seven birdies on the fourth.

Despite another bogey on the fifth, Korda made three consecutive birdies before the turn, then three more on a bogey-free back nine to leave her at 14-under 132 at the halfway mark of the U.S. LPGA Tour event.

"I started a little slow today, but all in all I think it was a great day," Korda said. "I putted really well, just kind of did the same things I was doing the first day. A little different score (from 64 on Thursday), but I'm not really disappointed with that."

With China's weeklong National Day holiday drawing to a close, Beijing's notorious pollution returned on Friday, casting a noxious pall over the Nicklaus Course at the suburban Pine Valley Golf Club.

Korda said that made it a little tougher for the players, despite the excellent condition of the course.

"The smog that's coming in right now, it's making it heavy, and it's harder to breathe out there," she said. "You cough a lot."

China's Feng Shanshan shot a 64, with nine birdies and no bogeys. She was tied for second at 12 under with Stacy Lewis of the United States, who had seven birdies in a bogey-free 66.

Feng said she overcame the pressure from the hometown crowd that had affected her on Thursday.

"Today I was like, 'I'm going to give it all,'" Feng said. "This is the time."

Lewis strung together six consecutive birdies on the back nine and has yet to card a bogey after two rounds.

"I got off to a little bit of a rough start, kind of got impatient on the greens," said Lewis, who is paired with Korda for Saturday's third round. "At the end of this golf course you can make some birdies, so I just need to stay patient and keep hanging in there."

Choi shot a 71 and was a stroke back at 11 under. She was followed by top-ranked compatriot Inbee Park, who was 9 under after shooting a 68.

"It was much better ball striking than yesterday, but I think I missed only one green out there today, gave myself a lot of opportunities," said Park, the winner of three majors this season.

"Especially seeing the scores yesterday, I thought this course was definitely scoreable. I kind of saw that on the practice round. And it was an even better score than I thought. I think you just got to go low here every day to win."