Ahead of today's free practice session the air temperature is 32 degrees C, while the track temperature is 48 degrees. The smog, which we have become accustomed to over the years, but was missing yesterday, has returned.

Ferrari appeared to have the edge yesterday, Felipe Massa, in particular, setting an incredible pace, according to his engineer Rob Smedley. The Brazilian topped the timesheets with his Spanish teammate, Fernando Alonso, finishing third.

Kimi Raikkonen split the scarlet duo but one couldn't help but feel that there was a certain uncertainty about the Lotus, particularly when it came to stability.

Having set the pace in the morning, Mercedes wasn't quite as strong in the afternoon when its drivers switched to the option (soft) rubber. In some cases the soft Pirellis didn't appear to last one lap, Lewis Hamilton making no secret of his unhappiness.

The dusty track and the tyre degradation meant there were plenty of incidents with Sergio Perez a 'victim' in both sessions.

Still making the headlines for all the wrong reasons, Red Bull is 'up there', as you would expect it to be', though Sebastian Vettel is unhappy about his pace.

Once again Marussia is looking strong, though it was only really Jules Bianchi who appeared to benefit, teammate Max Chilton missing much of the afternoon session due to a problem with his engine.

The Force India continues to impress, even if Pitpass sources insist all is not what it appears, while Williams still has much work to do.

The lights go green and Bianchi leads Gutierrez, Sutil and Ricciardo out into the Shanghai sunshine.

In moments almost all have been out, save Raikkonen who sits in his car as mechanics work on it.

While most return to their pits after an installation lap, Pic stays out and posts the first lap of the day (41.995). Moments later Van der Garde posts 41.924.

As Van der Garde raises the bar, sort of, with a 41.434, Perez is on track. The Mexican needs a good days after yesterday's errors, particularly the morning's incident when he crashed in the pitlane.

As one would expect, Perez goes quickest in the first two sectors, finally crossing the line at 38.769.

"I have very poor traction," complains the Mexican, this in spite of the fact that all yesterday's marbles have been swept from the track.

Elsewhere, an ambulance takes away a Marussia mechanic who is understood to have suffered a leg injury.

A 38.323 sees Raikkonen go quickest, while teammate Grosjean posts 38.717 to make it a Lotus 1-2.

No messing from Rosberg who goes straight to the top of the timesheets with a 37.699. All action thus far on the prime (medium) tyre.

On his out lap Hamilton is running at a ludicrously slow pace trying to save his tyres.

Perez improves to third (38.437) only to be demoted when Hamilton bangs in a 37.042. Moments later Vettel goes second, albeit 0.486s off Hamilton's pace.

While both Red Bull drivers are running a new rear wing, both Ferrari drivers are running a new front wing. Along with Webber and Maldonado the Ferrari duo are the only drivers yet to post a time.

Hamilton goes faster still, the first driver to break the 36s barrier (36.961), Mercedes looking to have recovered yesterday morning's form.

As Webber begins his first flying lap his car snaps wildly, a heart in mouth moment for the Australian who goes on to post a 37.905 and go fourth.

Alonso is the first of the Ferrari drivers to go out, the Spaniard going fifth with a 37.964. Moments later Massa goes sixth with a 38.099.

Webber improves with a 37.617 but remains fourth as Gutierrez fails to improves on 40.238. Seemingly, despite Hulkenberg currently being eleventh, all is not well at Sauber. Then again, the Toro Rossos are also off the pace.