Dissertations and Theses

Date of Degree

6-4-2019

Document Type

Dissertation

Degree Name

Doctor of Public Health (DPH)

Department

Environmental, Occupational, and Geospatial Health Sciences

Advisor(s)

Frank Mirer

Mary Schooling

Committee Members

Sheng Li

Brian Pavilonis

Subject Categories

Environmental Public Health | Occupational Health and Industrial Hygiene | Public Health

Keywords

Indoor Air Quality, Schools, Ventilation, Teachers, carbon dioxide

Abstract

Introduction:

Several recent studies have investigated the direct effects of carbon dioxide (CO2) at concentrations typically found in office buildings on occupant cognitive functioning. These studies have reported a significant association between (impaired) decision making ability and exposure to increased levels of CO2 (600 ppm versus 1500 ppm). The findings have serious implications in a classroom setting since the objective of schools is to provide an optimal environment for learning. If CO2 levels in schools are elevated, the teachers’ health and the students’ learning environment will be compromised. Higher CO2 levels could impact teachers’ and students’ cognitive functioning and hinder learning. The first aim of the study was to monitor and characterize New York City (NYC) public school teachers’ full shift exposure to CO2; A sub-aim was to assess whether school staff can manage air monitoring equipment in classrooms; The second aim was to evaluate the association of school building and classroom factors with higher CO2 levels; The third aim was to evaluate the association between higher CO2 levels and perceived air quality and teachers’ well being.

Methods:

Schools were selected with the assistance of the teachers union (United Federation of Teachers (UFT)). Air monitoring was conducted in 19 schools throughout NYC and each school was tested during two different times of the year; winter (heating season) and late spring (non-heating season). HOBO MX CO2 data loggers recorded CO2 concentrations, temperature, and relative humidity (RH) data inside classrooms continuously for one week. An online questionnaire was developed and deployed via Survey monkey. The questionnaire included 33 questions collecting demographic information, observations of classroom conditions and specific neurophysiological symptom data. A number of metrics of exposure were utilized in the study including a continuous variable representing maximum classroom CO2 concentration recorded over the monitoring period, and the number of CO2 measurements exceeding 1000 ppm during the teachers’ shift. Survey responses were evaluated through X2 tests (correlation analysis), Wilcoxon rank test and the relationships between exposures and health symptoms were assessed by logistic regression and multivariable regression analysis.

Results:

Peak CO2 levels during round 1 and round 2 ranged from 665 ppm to 5000 ppm and 679 ppm to 4085 ppm, respectively. Mean CO2 levels (7 hours; highest exposure day) during round 1 and round 2, ranged from 471 ppm to 2633 ppm and 462 ppm 2675 ppm, respectively. Approximately 66.3% and 66.2% of teachers reported experiencing fatigue in the winter and late spring seasons, respectively. About 29% and 32.4% of teachers reported the air quality in their classroom as being acceptable most of the time. It was determined that school staff could successfully manage air monitoring equipment in the classrooms (17 of 19 coordinators or 89% could successfully complete the five tasks). An association was identified between the number of CO2 measurements exceeding 1000 ppm and teachers’ perception of air quality. With more measurements above 1000 ppm, more number of teachers reported the need to open windows. An association of higher CO2 levels and the reported neurophysiological symptoms was not identified.

Discussion:

The study findings revealed that the majority of the teachers (77.5% and 74.3%) reported experiencing health symptoms while at the school. Peak CO2levels and percentage of measurements above 1000 ppm were also greater than reported in some studies. The results of this study underscore the need to reduce CO2 levels in NYC public school classrooms. A follow-up study could evaluate CO2 levels and classroom academic performance or standardized testing scores. Future studies could assess various interventions within the schools and classrooms to decrease CO2 levels.

Available for download on Thursday, May 27, 2021

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