Equipped with air purifiers in each classroom and planning to require anyone in schools to wear a mask, the Philadelphia School District will welcome back its 120,000 students in all buildings on Aug. 31 for the return of full-time in-person learning for the first time since the onset of the coronavirus pandemic, district officials announced Thursday.

“We have taken every precaution and added some precautions ... to ensure that we have appropriate mitigation strategies,” Superintendent William R. Hite Jr. said during a news briefing at Juniata Park Academy.

There, officials displayed the three types of air purifiers that will be placed in classrooms and throughout the district’s more than 200 buildings by the end of July. Using ActivePure Technology originally developed by NASA, the purifiers can eliminate 99% of the novel coronavirus within three minutes, said chief operating officer Reggie McNeil. They also eliminate other viruses, bacteria, mold, and fungi on both surfaces and in the air.

“It started off with testing out for the space station,” McNeil said. “It’s been tested by independent laboratories. It’s been tested in schools. It’s been tested without being in space. So, we’re pretty confident on the product.”

Money for the purifiers — a $4.5 million investment — came from federal funding, predominantly provided by the American Recovery Act, Hite said.

Ventilation and air quality in the district’s aging buildings was a point of contention between the teachers’ union and the School District during talks earlier in the year about safely returning to in-person classes.

Jerry Jordan, president of the Philadelphia Federation of Teachers, said Thursday that he’s encouraged by the district’s recent strategy.

“I hope that, first of all, it’s going to solve any dispute about the need for ventilation in our school buildings for the children and staff,” he said. “It also is something that I hope the parents and the local community will see as another layer of support in mitigating the virus, and that our buildings are going to be exactly what we’ve been asking for.”

Teachers are “anxious to get back to teaching kids face-to-face,” Jordan added. “There’s something to be able to walk by and smile at a child ... because of something they achieved, and to be able to give a high five to a youngster. You can’t do that, virtually, so teachers are really looking forward to getting back in front of the classroom kids.”

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Philadelphia’s announcement follows guidance from the Centers for Disease Control and Prevention, which last week recommended that schools fully reopen for in-person instruction in the fall. The CDC’s new guidelines suggest safety measures — like requiring unvaccinated children and staffers to wear masks and three feet of social distancing between students — but allows districts to devise their own solutions, acknowledging that achieving three feet of space may be improbable in more crowded schools like Philadelphia’s.

The district will require all students and teachers — regardless of vaccination status — to wear a mask.

A spokesperson later emphasized that the district is following the guidelines of the Philadelphia Department of Public Health, which may be updated before the school year begins.

Custodial crews will spend extra time before and after school hours cleaning, and the district will maintain its touch-free hand sanitizer stations and ensure all schools have ample supplies for frequent hand-washing, McNeil said. The district is also testing more than 1,000 touchless hydration stations, he said. Masking will also be required on public transportation and school buses, Hite said.

McNeil also said that the School District has removed “the equivalent of more than 20 miles of asbestos” from its buildings, with more environmental and structural improvements underway.

Hite said the district will also test all adults for the virus on a regular basis, as well as a random sampling of 20% of students attending school. The district will base its strategies on guidance from the CDC and Philadelphia Department of Public Health, he said.

A virtual, asynchronous schooling option will also be available to families uncomfortable with face-to-face instruction, Hite said, adding that more details will be made available later this month.

August will mark the first time since March 2020 that buildings are open for all Philadelphia students. In May, the district opened its buildings two days a week to students in prekindergarten through ninth grade, but only 27% of students and their families opted for in-person learning. Meanwhile, 10th through 12th graders didn’t return to classrooms at all.

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As vaccinations continue to increase and the city has largely reopened, coronavirus case rates in the Philadelphia region have remained low. But officials are eyeing the rise of the highly contagious delta variant, which has contributed to more than half of new cases nationally.

At least 60% of the School District workforce was vaccinated through its partnership with the Children’s Hospital of Philadelphia, Hite said. That number doesn’t include staffers who may have gotten the shot elsewhere, and the district does not require its workers to report their vaccine status.

» READ MORE: CDC recommends schools fully reopen but with masks for unvaccinated kids

Hite said the district doesn’t have final numbers yet on students who have been vaccinated, but it will be offering vaccine sites in schools during the summer.

“We want as many young people as possible to be vaccinated,” he said.

More changes were also announced Thursday with the surprise resignation of school board member Angela McIver, who has served on the district’s governing body since it was returned to local control in 2018. Her resignation is effective immediately.

McIver, a math educator and parent of children who attend district schools, said she’s leaving because of COVID-19′s impact on her small business, an extracurricular math program for elementary school students. She no longer has the time to dedicate to board work, she said.

McIver distinguished herself as unafraid to speak out — this spring, she was the lone board member to vote against the district’s $3 billion budget. At the time, she said the spending plan did not adequately fund extracurricular activities such as athletics, but overspent on school police, a move she said “tells us what we believe about our children.”

In farewell remarks to the board, McIver thanked her fellow board members and praised Hite for his “skillful leadership,” especially during the pandemic. She said the board’s work remained crucial to the city’s future.

”We have an opportunity to train future citizens and should be intentional about building critical thinkers and civic participation,” McIver said. “Public education is democracy in action.”

McIver’s resignation means Mayor Jim Kenney will have to reconvene the educational nominating panel to solicit and interview candidates for her replacement. After it chooses three names for Kenney’s consideration, the mayor has final say on the new board member.