Students, Teachers Endure Heat, Smog : Education: The first day of classes for city schoolchildren is marked by crowded classrooms and triple-digit temperatures.

A smoggy back-to-school heat wave with temperatures topping 100 degrees in the San Fernando Valley greeted schoolchildren who returned to classes Tuesday while bidding goodby to their last three-month summer vacation.

Beginning in July, all 616 schools in the Los Angeles Unified School District will operate year-round to make room for new students. Under the new plan, student vacations will be taken throughout the year.

“I’m a little nostalgic about it,” said Carpenter Avenue School Principal Joan Marks, who greeted new students and their parents in the auditorium of the Studio City elementary school.

Enrollment in the fast-growing district is expected to total more than 625,000 this year, district officials said. During the past two years, enrollment in the Los Angeles school district, the nation’s second largest, has increased by about 30,000 students.

Valley schools, which make up nearly 30% of the district’s total student enrollment, reported increases in already crowded primary grades. Final fall enrollment numbers will not be ready until next month, district officials said.

To make more classroom space available, 37 elementary schools in the Valley are operating on year-round schedules, with the remaining 103 elementary, junior and senior high schools scheduled to switch in July.

The prospect of attending school during the sweltering Valley summers began to hit home for teachers and students who have yet to begin the year-round schedule.

“It was 109 degrees in my classroom today,” said Linda Minster, an eighth-grade American history teacher at William Mulholland Junior High School in Van Nuys. “That is cruel and unusual punishment.”

At Taft High School in Woodland Hills, Principal Ron Berz said the extreme heat drained some of his students’ normal enthusiasm, at least during the first week of school.

“The students are usually pretty motivated and anxious to get back to school, but they were lethargic,” Berz said. “This is the hottest first day I can remember.”

The school board on Monday is scheduled to consider a $35-million plan to install low-cost, portable air-conditioning at the hottest 61 year-round schools, including 35 in the Valley where classroom temperatures routinely exceed 90 degrees during the summer. The plan is contingent upon Sacramento agreeing to give Los Angeles most of the $36 million remaining in the state’s air-conditioning fund, district officials said.

To combat the heat this week, principals at Valley schools are being allowed to call for shortened days, beginning Wednesday, district officials said.

School officials had more on their minds than the heat after a drive-by shooting Monday of a 15-year-old student who was leaving the campus of John H. Francis Polytechnic High School in Sun Valley.

The victim, Manuel Yepiz of Sun Valley, remained in stable condition at Northridge Hospital Medical Center, Los Angeles police said. Detectives, who believe the shooting was gang-related, said no arrests have been made.

But Principal Virginia Holt said the shooting was upstaged Tuesday by the excitement of students getting reacquainted after the summer off and the beginning of classes. “We have had a very quiet, peaceful first day,” she said.

On Tuesday there were three school police officers on the campus in response to the shooting, Holt said. Normally, there is one officer assigned to each campus.

Los Angeles police also increased patrols by the campus, where officers said members of several rival gangs attend school. The additional patrols are a routine at the beginning of the school year and were not prompted by the shooting Monday, police said.

“We put extra patrols out there to kind of set a tone,” said Lt. Michael Ranshaw, who added that there were no problems Tuesday. “So far, so good,” he said.

But despite the heat and fears of violence, many students said they were glad to return to school.

“I had a good vacation but I missed the teachers and my friends,” said Melissa Reiss, a third-grader at the Vintage Street Fundamental School in Sepulveda.

Reiss was one of the few in her class to have one of the Vintage Street school’s new blue, white and gray uniforms. School officials and parents voted in spring to begin a voluntary dress code that calls for students to wear uniforms. It is the second Valley school to try the experiment, which is meant to discourage the wearing of gang colors and make it easier for parents to dress their children.

“I have a very finicky child and this saves screaming fights in the morning over what to wear,” parent Barbara Friedrich said. “It also gives them a sense of pride and belonging.”