Student Performance and Absenteeism Related to IAQ

Transcription

1 Student Performance and Absenteeism Related to IAQ Balancing IAQ and Energy Conservation/Efficiency Objectives in Schools ASHRAE Summer Meeting Louisville, KY June 21, 2009 by Francis (Bud) J. Offermann PE CIH Indoor Environmental Engineering San Francisco, CA (415)

2 Student Performance / Absenteeism Student performance is a critical factor in securing operational funding. Student and teacher attendance influence student performance. IAQ impacts both student and teacher attendance

3 School ventilation and disease Chicago ventilation intervention study. Elizabeth McCormick Open Air School Published in 1910 by the United Charities of Chicago City of Chicago 1.6% (4,700) children with TB 5% (14,600) children anemic / weakened

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9 Chicago School Ventilation Study Winter month of at the Open Air school 30 students no open infectious students 16 had been and 10 still exposed to TB at home 17 1st stage TB 2 with tubular glands 11 pre-tubercular 66% (20) had a fever of o F.

10 Results of Ventilation Study Winter month of at the Open Air school prevalence of fever reduced from 66% (20) to 7% (2) average weight gain of 3.5 lbs/student Authors concluded that hot dry air develops and spreads diseases, and particularly, tuberculosis.

11 Biophysical Model Stimuli Generation Rate area emission rate Indoor Concentration of Stimuli Occupant Exposure To Stimuli Occupant Sensitivity To Stimuli Occupant Reaction To Stimuli ventilation filtration surface deposition reaction Stimuli Removal Rate time exposed breathing rate protection expectation predisposition thermal skin eyes/nose respiratory CNS

12 Indoor Environmental Stimuli Indoor Stimuli Chemical Thermal Acoustics Lighting Radiation Ergonomics

13 Indoor Air Stimuli Indoor Air Stimuli Chemical Stimuli Thermal Stimuli Particles Gases Temperature Biological Reactive Gases Humidity Non-biological Unreactive Gases Air Speed / Turbulence Radiation

14 Indoor Air Concentrations Indoor Outdoor Underground Sources of Stimuli Indoor Air Concentrations of Stimuli Removal of Stimuli Ventilation Air Cleaning Reactivity Surface Deposition Occupant Respiration

15 Student Performance and IAQ Hypothesis Higher stimuli concentrations Higher student impacts Lower student performance Pathogens Mold and other allergens Formaldehyde and other VOC s Elevated temperatures, pheromone emissions?? Body odor Infectious disease transmission Asthma trigger and respiratory irritation Eye, nose, and respiratory Irritation Lethargy/distraction Dissatisfaction/Distraction Attention Recognition Comprehension Motivation

16 Studies of IAQ and Student Performance and Absenteeism Intervention tests; temperature and outdoor air ventilation Denmark, Wargocki et. al. (2006) Carbon dioxide and student absence study. USA, Shendell et. al. (2003) Student performance and outdoor air ventilation. UK, Bako-Biro et. al. (2008) Student performance and outdoor air ventilation via CO 2. USA. Shaughnessy et.al (2006) Effects of School Environments on Performance: A Review USA. Mendell et.al (2006) Wargocki et.al. Healthy Buildings 2006

17 Student Performance and Ventilation 5 intervention tests in 6 identical classrooms Denmark (Wargocki et. al. 2006) Doubling ventilation per occupant from: 4.7 L/s (10 cfm) to 9.4 L/s (20 cfm) Improves student performance 14.5%. Wargocki et.al. Healthy Buildings 2006

18 Student Performance and Temperature 5 intervention tests in 6 identical classrooms Denmark (Wargocki et. al. 2006) Reducing air temperature 1 o C Improves student performance 3.5%. Wargocki et.al. Healthy Buildings 2006

19 Student Absence and Carbon Dioxide Concentrations Carbon dioxide and student absence study. Shendell et. al. (2003) 14 schools - Idaho and Washington, USA K traditional classrooms 25 portable classrooms A 1,000 ppm increase in CO 2 was associated with a 10% - 20% increase in student absence (p < 0.05). Estimated outdoor air supply rate based on carbon dioxide measurements was NOT associated with student absence. Yearly attendance was 2% higher (p < 0.001) in traditional than in portable classrooms. Shendell et.al., LBNL

20 Student Performance and Ventilation Student performance and outdoor air ventilation. Bako-Biro et. al. (2008) 8 schools - Reading, UK, Grade 5 Intervention study. Portable mechanical outdoor air ventilation system installed through window non-mechanically ventilated classroom to provide a constant indoor temperature while outdoor air ventilation rates were changed. Computerized assessment tests administered to measure student performance. Bako-Biro et.al., Indoor Air 2008

21 Student Performance and Ventilation Portable HVAC system. Computerized assessment tests Bako-Biro et.al., Indoor Air 2008

22 Student Performance and Ventilation Increasing outdoor air ventilation rates a factor of 4.25 per person: From 1.6 L/s (3.4 cfm) to 6.8 L/s (14.4 cfm): Resulted in the following: - 3% increase in reaction times - 8% increase in picture recall - 15% increase in word recognition Bako-Biro et.al., Indoor Air 2008

23 Performance and Ventilation Rates via CO 2 54 Elementary Schools 5 th Grade Classrooms USA. Shaughnessy et.al (2006) R.J. Shaughnessy et.al. Indoor Air- October, 2006

24 Performance and Ventilation Rates via CO 2 54 Elementary Schools 5 th Grade Classrooms USA. Shaughnessy et.al (2006) R.J. Shaughnessy et.al. Indoor Air- October, 2006

25 Effects of School Environments on Performance: A Review - Mendell (2006) Mark J. Mendell Indoor Environment Department, Lawrence Berkeley National Laboratory Effects of School Environments on Performance and Health Primary Results No causal relationships established Strongly suggestive evidence linked higher NO 2 in schools to decreased attendance Suggestive evidence linked low outdoor air ventilation to decreased performance in children M. J. Mendell et.al. LBNL-51780, 2006

26 Conclusions Student performance and attendance IS impacted by the air quality in the school. More research is needed to know: the magnitude of the impacts. what are the specific environmental factors that are actually causing reduced student performance and attendance, and the dose response. how these causative environmental factors can be mitigated

27 ? Questions? Francis (Bud) J. Offermann PE CIH