Starting and ending the school year sooner? Philadelphia School District officials want to do just that, citing a desire to get as much of the term in as possible before Memorial Day, when student attendance trails off considerably.

But the Philadelphia Federation of Teachers, officially, seems not thrilled. In an email to his members, PFT president Jerry Jordan cited "serious concerns" about the proposal. The concerns center on the health of the city's children, Jordan said.

"Philly's schools, on average, are 70 years old, and most have no air conditioning. After sitting closed for several weeks in the summer, these buildings become extremely hot. As you know, the days between late August and early September can make a significant difference in the indoor air quality in our schools. That is a huge concern in a city where about 25 percent of schoolchildren have asthma or related respiratory concerns," Jordan wrote.

The PFT has made its concerns known to the district. It encouraged members - district teachers, counselors, nurses, secretaries and other school staff - to weigh in, too.

The district has also asked parents and other community members to share their thoughts in a survey. The SRC is scheduled to vote on the new calendar at its December meeting.

Chief academic officer Cheryl Logan has said that the district did take building temperatures into consideration in making their recommendations. She said a study of average temperatures showed that there is little difference in average temperatures in early September and late June.

Under the current proposal, students would start and end school Sept. 5 and June 14 in the 2017-18 school year, and start Aug. 27 and end June 4 in the 2018-19 school year.

Teachers would report earlier, too - Aug. 28 next year, and Aug. 20 the following year.

The PFT does not have to give its consent for the calendar change. District officials are still adhering to the most recent teachers' contract, even with the changes, keeping 181 instructional days for students and 188 for teachers.

What do you think? Are the proposed calendar changes a good thing, or a bad one?