Metropolitan Learning Center (MLC)

Most MLC students spend the day in well-ventilated classrooms

Running air purifiers consistently is critical in low airflow rooms at MLCand brings most MLC classrooms to excellent clean airflows

MLC's HVAC system delivers air-change rates that typically range from insufficient to good for classrooms and other learning spaces. District measurements show most MLC classrooms meet health-based goals for ventilation. The best way to reach healthy air targets is with a combination of building ventilation and effective in-room filtration, and while ventilation in MLC is mostly good, some rooms are too low, and it is critical that MLC receive ongoing support for placing and using in-room air purifiers.

The one air purifier originally assigned to MLC‘s rooms is insufficient and undersized in some of MLC's classrooms and large spaces. Two or more air purifiers per classroom can substantially improve air quality, reduce respiratory viruses and air pollutants, and achieve effective air cleaning, while running at quiet settings.

Two air purifiers are needed in some of MLC's classrooms, auditorium, library, and kitchen to more effectively clean the air. That’s why the Oregon Health Authority provided additional free air purifiers for MLC in 2023. The district received these units, enough for a second air purifier in the MLC rooms that need them. But to our knowledge, the district never delivered them to the school. MLC's second air purifiers are in district storage. Teachers and staff at MLC have also not gotten great guidance on running their one air purifier or why using two matters. At other PPS schools with the same problem, we've been able to help get this sorted out, especially when parents at a school work with us. To connect and support next steps for clean classroom air at MLC, join our MLC group, and learn more about MLC‘s air quality below.

Without air purifiers, MLC does not have clean indoor air in the parts of the school

One air purifier is undersized for some MLC classrooms

With only one air purifier per classroom, some MLC classrooms still lack clean air:

Although the Intellipure air purifiers originally assigned to MLC greatly improve the school's clean airflow rates, they are insufficient in some MLC classrooms. Even with an Intellipure air purifier running at its reasonable noise level (half speed), the classroom with the lowest ventilation from the HVAC system — room 108 — is still far below healthy airflow targets. With room 108 at 3.2 air changes per hour, kids’ and staff’s viruses in their respiratory aerosols linger for over 43 minutes.

At 3.2 air changes/hour, 43 minutes is how long it takes for the HVAC system and Intellipure air purifier to clear out 90% of the respiratory aerosols being produced when kids and staff breathe, talk, sing, cough and sneeze.

With only one air purifier per classroom:

✘ Worst-airflow classroom (room 108) is still less than 4 air changes per hour

✘ 1 other MLC classroom has less than 5 air changes per hour

✘ 2 classrooms are between 5 and 6 air changes – below recommendations

If one Intellipure unit is running at its quiet noise level, 17 classrooms meet our minimum goal for healthy ventilation and filtration of 6 air changes per hour or more, clearing 90% of aerosols out in 23 minutes or less.

MLC needs two air purifiers in some rooms to clean classroom air

Two air purifiers make a big difference — but some rooms would still fall short

In some MLC classrooms, the baseline ventilation is so low that two air purifiers alone cannot fully solve the problem. Even so, using both an Intellipure and a Medify Pro still makes a major difference in these rooms, reducing exposure for students and staff compared with using only one unit, or none.

For example, MLC‘s worst-airflow classroom — Room 108 — is 4.9 air changes per hour even with two air purifiers. Although this is still below the minimum healthy air target of 6, it is far better than the 2.4 air changes per hour the room gets with no air purifiers running.

Visualizing how much air purifiers improve MLC classroom airflow

The graphs below show how much ventilation most MLC classrooms get without any air purifiers running. They also show how the addition of one air purifier per classroom shifts the rooms’ airflow rates higher , moving most rooms above health-based benchmarks for clean air. Adding two air purifiers to the rooms that fall short with one unit moves the low-airflow rooms into higher ranges of airflow. Although two air purifiers added to the below-target classrooms would still leave 1 classroom short of 6 air changes per hour, our current recommendation for a mix of some classrooms having one air purifier and some having two would move most classrooms into the healthy air range above 6, and the lowest airflow classrooms would be much improved.

Number of classrooms vs air changes per hour

MLC needs its second air purifiers in classrooms, not in storage

The storage of MLC’s second air purifiers needed in its below-target classrooms — as well as the storage of other PPS schools’ second units — has left resources meant to improve classroom health and safety sitting unused, when they could be making a meaningful difference to health and learning. MLC's second air purifiers should not be left in district storage when district data shows MLC needs more air filtration capacity in its low-airflow rooms. These second units should be in classrooms and other school spaces, providing critical benefits of clean indoor air, such as reduced illness, improved learning, and better attendance.

Distributing and using this clean air infrastructure needs action at all levels, from district leadership to the classroom. Parents, caregivers, and school staff also have key roles to play to help get MLC's second air purifiers out of storage and into classrooms and ensure clean classroom air. Join SIAFOS and our MLC group to connect with others who care about clean, cool classroom air at MLC.

How can you help with clean air for MLC?

Let's get MLC's second air purifiers out of storage and into MLC's low-airflow classrooms — Sign up to help fix this so these air cleaners get delivered and running quietly to keep MLC classroom air clean!

Two air purifiers running at quiet settings in each low-airflow classroom would provide more air filtration to the one MLC classroom that does not even get 3 changes of air per hour and the 8 classrooms that only get between 3 and 6! Using multiple air purifiers would also ensure MLC‘s library and other key spaces get better air quality, too.

Join us to be part of a group of parents and community members advocating for strategic, effective, and science-based planning for sufficient ventilation and filtration capacity in PPS schools — including MLC. PPS air quality efforts have cycled between strong progress as well as periods of inaction and missteps. We are now working more collaboratively with district leadership, yet long-standing gaps in ventilation and air filtration persist across the district — which is why parent, staff, and community involvement at the classroom level, school level, and district level remains so important.

Changing our schools in PPS to have good air quality practices only happens when families and staff work together. When you join us, we’ll connect you with others and share simple processes that help PPS kids and staff, including kids and staff at MLC, learn and work in classrooms with cleaner air, less illness, and healthier learning environments. Sign up below to join our organizing for PPS air quality!

*Notes on our numbers

Air changes per hour given on this page are “equivalent” and include ventilation and filtration.  These numbers are based on the district’s airflow report for MLC, conducted in August 2021 (available at safeairoregon.org/original-airflow-reports) but corrected gaps and errors.