César Chávez K-8 School

César Chávez students spend the day in poorly ventilated classrooms

Unless air purifiers are run consistently

Like nearly all PPS schools, César Chávez's HVAC system delivers low air-change rates in classrooms and other learning spaces. The district's own measurements show that César Chávez does not 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, but ventilation in César Chávez is poor, and it is critical that César Chávez receives ongoing support for placing and using in-room air purifiers.

The one air purifier originally assigned to César Chávez‘s rooms is insufficient and undersized for César Chávez 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 César Chávez's classrooms, cafeteria, and library to more effectively clean the air. That’s why the Oregon Health Authority provided additional free air purifiers for César Chávez in 2023. César Chávez received enough additional units that each classroom should have two air purifiers each! Ensuring César Chávez staff and families understand why they and their students benefit from running both units every day is important to classrooms meeting or approaching healthy air targets. To connect and support next steps for clean classroom air at César Chávez, join our César Chávez group, and learn more about César Chávez‘s air quality below.

Without air purifiers, César Chávez does not have clean indoor air

If no air purifiers are running:

✘ Coughs and sneezes in the typical César Chávez classroom linger and hang in the air for over 56 minutes

The median rate of airflow from the HVAC system to classrooms at César Chávez is only 2.5 air changes per hour.*

At 2.5 air changes per hour, it takes the HVAC system 56 minutes to clear out 90% of the respiratory aerosols being produced when kids and staff breathe, talk, sing, cough and sneeze. That is far too long for virus-laden respiratory aerosols and other indoor air pollutants to fill the air students and teachers are breathing.

But the median does not show how bad the lowest-ventilation rooms are …

✘ Classroom with the lowest ventilation: M100

         0.0 air changes per hour

With airflow this low, how long do kids’ and staff’s viruses linger in room M100’s air?

>4 hours and 36 minutes

✘ Without air purifiers, 9 more César Chávez classrooms have less than 2 air changes per hour

At 2 air changes per hour, it takes the HVAC system 1 hour and 9 minutes to clear 90% of the respiratory aerosols.

✘ 8 classrooms are between 2 and 3 air changes per hour & 12 more classrooms are between 3 and 6 – all below recommendations

Only 1 classroom meets our minimum health-based airflow target for the HVAC system alone of 6 air changes per hour or more, clearing 90% of aerosols out in 23 minutes or less.

Rm 19: 6.8***

***Good airflow:
Just 20 minutes to clear 90% of aerosols in room Rm 19

Classrooms that meet the minimum goal of 6 have good airflow, but can be even better. At 12 air changes per hour, aerosols clear out by 90% in under 12 minutes.

Schoolwide score: 83% – B
Based on median airflow from HVAC + 2 air purifiers
Second air purifiers delivered & placed
Teacher education packets provided

Sign up here to join the César Chávez group

About these ventilation measurements

These numbers come from airflow testing done in nearly every room of every PPS building, before the district resumed in-person learning in 2021. We carefully reviewed the district’s results, compiled and maintain a districtwide database from the airflow reports, and corrected gaps and errors in the data so that classroom ventilation and filtration are represented accurately. Our analyses provide ventilation rates from the HVAC system alone and show how total clean airflow increases when in-room air purifiers are used.

To learn more about the district airflow testing and how SIAFOS corrected the data, see this excerpt adapted from our McDaniel High School Air Quality Report: District airflow measurements & SIAFOS analyses. For the full room-by-room values, corrections, and calculations for this school, see César Chávez K-8 School Analysis by SIAFOS.

One air purifier is undersized for César Chávez classrooms

With only one air purifier per classroom, César Chávez classrooms still lack clean air:

Although the Intellipure air purifiers originally assigned to César Chávez improve the school's clean airflow rates, they are insufficient in César Chávez 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 M100 — is still far below healthy airflow targets. With room M100 at 0.8 air changes per hour, kids’ and staff’s viruses in their respiratory aerosols linger for over 2 hours and 53 minutes.

At 0.8 air changes/hour, 2 hours 53 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 M100) is still less than 1 change of air per hour

✘ 3 more César Chávez classrooms have less than 2 air changes per hour

✘ 10 classrooms are between 2 and 3 air changes per hour & 14 more are between 3 and 6 – all below recommendations

If one Intellipure unit is running at its quiet noise level, only 3 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.

César Chávez needs two air purifiers per classroom to clean classroom air

With the two air purifiers per classroom placed and in use, over one-third of the school meets the minimum healthy air target

With two of the air purifiers the district already owns running at their best noise levels (one Intellipure at half speed and one Medify Pro at speed 2), 14 out of 31 César Chávez classrooms would be at 6 air changes per hour or higher. That includes 5 classrooms above an excellent 8 air changes per hour. Viruses, mold spores, dust and allergens, wildfire smoke, and other air pollutants would clear out by 90% in as little as 14 minutes.

The median clean airflow with two air purifiers per classroom would be 6 air changes per hour. At 6 air changes, the typical classroom at César Chávez would meet our minimum clean air goal, resulting in a solid level of respiratory protection.

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

In some César Chávez 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, César Chávez‘s worst-airflow classroom — Room M100 — is 3.9 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 0.0 air changes per hour the room gets with no air purifiers running. Room M101 follows the exact same pattern: it reaches only 3.9 air changes per hour with two air purifiers, meaning that viruses, bacteria, asthma triggers, and other air pollutants linger in the classroom air for over 35 minutes. But without both air purifiers, Room M101 gets literally no air changes per hour from the HVAC system. Room 115 is a third example with the same story. Even when operating two units, Room 115 is only 4.1 air changes per hour, but that airflow level is an important health protective improvement over the 1.1 air changes the room gets if relying on the HVAC system alone.

Visualizing how much air purifiers improve César Chávez classroom airflow

The graphs below show how little ventilation most César Chávez 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 but still leaves most rooms below health-based benchmarks for clean air. With two air purifiers per classroom, the pattern changes. Although two air purifiers still leave most classrooms short of 6 air changes per hour, having two units per room moves 14 classrooms into the healthy air range above 6, and the lowest airflow classrooms are much improved.

Number of classrooms vs air changes per hour

No air purifiers
HVAC only

Over half of César Chávez classrooms have extremely poor airflow without air purifiers running. Over half of the classrooms do not even reach 3 air changes per hour from the HVAC system.

One air purifier

One Intellipure air purifier running at its reasonable noise level still leaves most classrooms with poor airflow.

Two air purifiers

Over one-third of the classrooms have good levels of clean airflow with two air purifiers. 45% of classrooms are over our minimum goal of 6 air changes. And the below-target rooms get much better airflow with 2 units than they did with only one.

Next steps: support and strengthen César Chávez's clean air practices and daily use of two air purifiers

César Chávez received enough additional air purifiers that every classroom should have two units. The next step is strengthening and sustaining how César Chávez uses daily air quality practices so that classrooms, lunchtime, after school activities, and school events consistently get clean air. Many schools are still building their understanding about how multiple air purifiers running quietly together are needed to clean the air in a full classroom of 20 or 30 kids. Some guidance on how and when to use both units has been shared at César Chávez. In practice, running two air purifiers, instead of just one, moves clean airflow toward health-protective benchmarks, providing critical benefits of clean indoor air, such as reduced illness, improved learning, and better attendance.

Ongoing commitment to placing 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 support daily use of two air purifiers in César Chávez classrooms and ensure clean classroom air. Join SIAFOS and our César Chávez group to connect with others who care about clean, cool classroom air at César Chávez.

The data shows how César Chávez can improve air quality, reduce illness, and increase attendance

Why were second air purifiers delivered for every César Chávez classroom?

In 2023, PPS received 3500 free air purifiers — enough additional air purifiers to provide a second unit for every classroom in the district and other learning spaces as well. Instead of fully delivering on that commitment, previous district leadership used a flawed decision-making process that sent most units into storage rather than into classrooms. César Chávez was one of 68 schools affected by this choice.

Errors in airflow calculations, inappropriate averaging methods, and misleading communications under previous leadership resulted in PPS erroneously concluding that schools like César Chávez did not need second air purifiers. However, SIAFOS parents helped César Chávez get their second units out of district storage and to the school. Unfortunately, other schools' units still remain in storage. And a full explanation of how the storage of air purifiers meant to be cleaning classroom air occurred, and how PPS can correct course is available at:

In our analysis that corrects gaps in PPS’s airflow report, we have fixed errors and calculated classroom airflows with air purifiers running at speeds teachers can actually use.

Our airflow analysis provides room-by-room airflows at César Chávez when rooms have no air purifiers, vs. one air purifier, vs. two air purifiers.

See our full airflow analysis for César Chávez K-8 School here.

Highlights from our comprehensive room-by-room analysis of César Chávez airflows

  • With no air purifiers, 18 out of 31 classrooms are below 3 air changes per hour
  • The HVAC system only provides the library with 1.5 air changes per hour, and the cafeteria is only 2
  • With two air purifiers, no classrooms are under 3 air changes per hour, and 14 meet or exceed our minimum goal of 6 air changes per hour

Other SIAFOS analyses, reports, and campaigns

Learn more about indoor air quality in PPS with some of our other analyses, reports, and campaigns:

McDaniel High School Air Quality Report — our 144-page flagship report using the McDaniel cluster as a case study for districtwide problems, and solutions, for clean air

Benefits of Clean Indoor Air — improving air quality in PPS will increase student performance, reduce absences and educator sick days, improve health for students, staff, and surrounding communities, improve equity, and help mitigate impacts of climate change

Teacher Feedback on PPS’s Fall 2025 Temporary Cooling Measures — report on our survey of teachers in the 15 schools that received temporary cooling equipment in the fall 2025 heat wave

Sign-On Letter to Show Your Support for Clean Air in PPS — add your voice to our public letter calling for health-based ventilation and air quality in PPS

Airflow 101 Handouts: Understanding Airflow Sources in the Classroom and How Using Two Air Purifiers Allows Quiet Speed Settings

Poor airflow in César Chávez and other PPS schools is why we worked with parents across the district in spring 2023 to advocate that PPS classrooms need additional, high quality air purifiers to provide safe air to kids now, when HVAC system overhauls will take the district years to do in all schools and a mix of ventilation from HVAC systems and in-room filtration is the best approach for clean classroom air in both newly modernized buildings and older buildings alike. Just as we were advocating to the school board for the need for additional filtration capacity in PPS classrooms, the Oregon Health Authority announced a program offering free Medify air purifiers to any K-12 schools in Oregon. When it became clear that district staff were not planning to sign up for any of the free air purifiers from OHA, we made the case for why César Chávez needed these additional units. Parents from across the district joined SIAFOS in advocating that the district take full advantage of the program.

How can you help with clean air for César Chávez?

Let’s support César Chávez in using clean air tools well — Sign up to help ensure air purifiers are in place and running quietly to keep César Chávez classroom air clean!

Two air purifiers running at quiet settings in each classroom would provide more air filtration to the 18 César Chávez classrooms that do not even get 3 changes of air per hour and the 12 classrooms that only get between 3 and 6! Using multiple air purifiers would also ensure César Chávez‘s cafeteria, where kids pack in close to eat lunch, and 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 César Chávez. 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 César Chávez, 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 César Chávez, conducted in August 2021 (available at safeairoregon.org/original-airflow-reports) but corrected gaps and errors.