ARUNDEL — Pupils at the Mildred L. Day School will attend classes together for the first time in November, ending two months of split-session schooling.

The school has acquired six modular classrooms to be used by pupils currently attending school in half-day shifts. An air quality problem forced the closure of a large portion of the building this summer, prompting the school to hold classes in shifts to accommodate all the pupils.

The new classrooms will be ready Nov. 2 and will be used for the remainder of the academic year.

“This is a step in the right direction,” said Superintendent Richard Abramson. “I’m anxious to see it come to fruition. I think it’s safe to say that this has been the fall from hell. Nobody has had it easy.”

An air quality test in July, spurred by staff and pupil complaints of respiratory problems last year, revealed that sections of the school contained dangerously high concentrations of carbon dioxide and mold spores. Subsequent reviews of the building also revealed poorly contained asbestos tile in those areas.

The sections of the building were sealed off before school began in September, eliminating much classroom space and forcing pupils to attend classes in half-day shifts. Pupils in grades K-3 currently attend classes before noon, while grades 4-8 go to school in the afternoon.