BERLIN (AP) _ Schools suspended outdoor sports and motorists were pulled off the roads Monday as West Berlin authorities extended the city's first smog alarm to a second day.

A police spokesman said that since the alarm took effect Sunday morning, 14,000 motorists had been pulled over at 71 special ''smog roadblocks'' throughout West Berlin and told to park their cars on the spot until further notice.

More than 1,150 drivers who could not convince police they did not know of the driving ban were fined 40 marks ($22), said the police official, who spoke on condition of anonymity.

In the Communist-ruled eastern zone of the divided city, no smog precautions were reported as traffic dominated by East Bloc-made cars with far dirtier exhausts than in the West continued without restriction.

In the West German state of Lower Saxony near the East German border, authorities declared a smog alert in the Braunschweig-Wolfenbuettel region and told industries to temporarily cut emissions by 40 percent.

A smog alert, an advisory that is not as serious as a smog alarm, also was declared in Hamburg.

The smog alarm in West Berlin was due to a coincidence of below-freezing, almost windless weather and heavy industrial emissions coming from surrounding Communist East Germany.

''The outlook is problematic,'' a city Environment Department spokesman said of a weather forecast that held out little hope for a rise in temperature until Wednesday.

With all traffic but public transit and cars equipped with special anti- pollution devices banned from West Berlin roads, the number of riders in buses soared from the usual 500,000 to 900,000 by midday, city transit officials said.

To handle the crush, 150 extra buses were added to the usual fleet of 1,500, and 90 buses were rented from private firms.

Transit officials reported smooth traffic and few citizen complaints.

Meanwhile, schools canceled outdoor sport activities and allowed 193,000 students to arrive for classes two hours late to avoid the peak early morning smog period.

Public buildings were ordered to keep thermostats no higher than 65 degrees to cut down on heating system emissions. If the smog alarm lasts longer than 72 hours, public buildings will have to reduce thermostats to 59 degrees, officials said.

The elderly and people with respiratory ailments were strongly recommended to stay indoors and keep their windows shut.