1/ Thanks to Oregon Department of Education for inviting @Wymelenberg and me to speak with a very large number of school officials in the State today about effective layered risk reduction, proven technologies, & variations across different types of school buildings/classrooms.
2/ 55 minute presentation w/ 35 minute GREAT Q&A period. Major kudos to the Department for their proactive approach to making schools as safe as possible prior to re-opening.
3/ Schools across US are suffering from confusing & inadequate guidance on ventilation & portable air filtration systems, & their importance for signif' reducing inhalation dose of virus-laden aerosol particles. Info available, but often not where schools are looking.
4/ I would personally welcome the opportunity to speak with the Dept of Education in ANY state in the US if asked. This is a critical moment for school districts across the nation to get this right and not waste federal funds they receive.
5/ Every school building and even classrooms within school buildings is different, but there are ways of addressing these differences effectively. It is NOT rocket science. Let's get the job done to reduce risk by 90 to 95% (or more) across EVERY school. Just Do It!
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1/ Investment in engineering and computer science education has a significant return on investment (ROI) to states.
Proud of the great ROI that the Maseeh College of Engineering and Computer Science provides the State of Oregon.
2/ Every dollar that the State spends on helping to educate one of our students yields a 320% ROI over 10 years, or 12% compounded annually.
3/ Based on a detailed analysis of graduates who stay and work in Oregon, their starting salaries, incremental annual salary increases, and use of a State income tax calculator ….
1/ Really enjoyed the National Conversation on Indoor Air and Schools during the Pandemic this morning and honored to have participated. Thanks to @polsiewski.
2/ One important outcome was general agreement that schools will continue to struggle to do the right thing to re-open until @CDC does a better job of guiding, particularly on making improved ventilation a prominent risk reduction step.
3/ Additional guidance on portable HEPA air cleaners and avoidance of ineffective technologies is also needed. A lot of great discussion and agreement by experts on a number of important issues that are missing from @CDC guidance.
1/ One of my slides. Cost of good portable HEPA filter system in a 600 to 800 square ft classroom with 25 students (equivalent ACH increase of 2.7 to 3.5/h). Cost is broken down by classroom and student.
2/ Cost = year 1 capital cost + annual recurring costs for filters + electricity at $0.11 per kW-hr.
Total 3-year cost per classroom < $790 (< $11/student for 75 students over 3 years).
3/ If school has 50 classrooms (larger than my K-8 school) the total cost over 3 years < $40K for entire school. Less for less classrooms.
If noise is an issue can go with 2 HEPA air filters per classroom at lower setting for around $20/student.
1/ Tragedy in Texas. When I was Chair of @ut_caee at UT Austin we implemented a new strategic vision that revolved around water, energy, growth of the built environment, and innovations in infrastructure that tie these elements together as a COMPLEX system.
2/ I was so proud of our early-career faculty who led an effort, for example, to develop a new graduate area in Sustainable Urban Systems (SuS) that rapidly grew into one of the most in-demand graduate areas in our department. Great effort. Great success.
3/ The ongoing tragedy in Texas reflects the importance of systems-oriented thinking to make cities, states, regions, and countries more resilient, and to understand the connection between built & natural environments as climate continues to change.
Portable HEPA Filter Systems. 1/ The cost of retrofitting EVERY public school classroom in the entire US w/ a portable HEPA air filter w/ CADR = 300 cfm is approximately $1 billion w/ recurring cost of about $300M/yr for replacement filters. To be clear, EVERY single classroom.
2/ For a classroom that holds 20-25 students, say 600 to 700 ft2 w/ ceiling height of 9 ft, this portable HEPA unit will yield approx equivalent increase in ventilation (equivalent ACH increase) of 3/hr. For a classroom under-ventilated to 2 ACH the bump up is to 5 ACH!
3/ That leads to a 60% reduction in inhalation dose of aerosol particles. Capacity exists. It can be done now.
1/ Ventilation of Schools. My experience working with public school districts for more than two decades is that classrooms are, in general, woefully underventilated (and that's before COVID-19 times!). Others have found the same.
2/ Some results from a 4-yr study involving 7 high schools of different ages & construction, & 46 classrooms (focus on occupied day - plot at right). Approx 80% of classrooms = permanent. Red bar shows approx ASHRAE 62.1-2019 ventilation rate (small variations around bar).
2/ For permanent classrooms, median ventilation rates are less than 50% of ASHRAE 62.1-2019, w/ mean values approx 40% lower. Schools all had mechanical systems and capability of much greater ventilation. When asked why, our team was told (firmly) - energy savings ($$).