OK-AIR: Testing classroom air cleaners and upper-room UV air treatment to improve indoor air quality and reduce sick-related absences in Oklahoma early care and education (ECE) schools
| ISRCTN | ISRCTN78764448 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN78764448 |
| Registration at Open Science Framework (OSF) | https://doi.org/10.17605/OSF.IO/RTZYG |
| Sponsor | University of Oklahoma |
| Funders | Oklahoma Partnership for School Readiness (OPSR) Clearinghouse, U.S. Environmental Protection Agency |
- Submission date
- 04/03/2026
- Registration date
- 05/03/2026
- Last edited
- 05/03/2026
- Recruitment status
- No longer recruiting
- Overall study status
- Ongoing
- Condition category
- Infections and Infestations
Plain English summary of protocol
Background and study aims
Young children (from birth to 5 years old) spend many hours each week in early care and education classrooms. During the school year, viruses that cause colds, flu, stomach illness, and other infections can spread easily in busy classrooms. Air in classrooms can also contain particles and other pollutants that may affect children’s breathing and comfort. Two commonly used approaches to improve indoor air are: (1) portable air cleaners with high‑efficiency filters, and (2) upper‑room ultraviolet germicidal irradiation (UVGI), which uses UV light near the ceiling to help inactivate germs in the air. However, there is limited real‑world randomized evidence in Head Start/early childhood classrooms on whether these approaches reduce illness‑related absences.
The OK‑AIR study aims to find out whether adding portable air cleaning and/or upper‑room UVGI in Head Start classrooms can: (1) reduce sick‑related (infectious illness‑related) absences among children, (2) improve indoor air quality, and (3) reduce detection of selected viruses on classroom surfaces. We will also explore whether improved classroom environments relate to children’s social‑emotional development as rated by teachers.
Who can participate?
Participation involves Head Start centers and classrooms in Oklahoma. Children include aged birth to 5 years who are enrolled in participating Head Start classrooms may be included if their parent/guardian provides consent (and any required authorization for relevant program health information). Parents/guardians will be asked to complete a questionnaire about the child’s health and home environment and to provide consent/authorization. Teachers and center directors/staff in participating sites will complete surveys and provide information needed for study procedures (such as daily attendance reasons and teacher ratings).
What does the study involve?
This is a school‑based study where classrooms are assigned by chance (randomized) to different indoor air approaches. Depending on the cohort and classroom assignment, classrooms may receive: (1) No added devices beyond usual operations (control), (2) Portable air cleaning/filtration using stand‑alone units with high‑efficiency filters, (3) Upper‑room UVGI fixtures installed high on the wall/near the ceiling, or (4) Both portable air cleaning and upper‑room UVGI (Cohort 1 only).
Study activities include: (1) Daily attendance tracking, where teachers record whether each child is present and, if absent, the reason (including whether the absence is sick‑related); (2) Indoor air quality monitoring, where each classroom has a monitor that measures indoor air conditions such as particle levels and temperature/humidity during the school year; (3) Environmental surface sampling, where a few times per year, trained staff collect swabs from classroom surfaces (for example dining tables and bathroom flooring), and these swabs are tested in a laboratory for genetic material from selected viruses (e.g., influenza, RSV, SARS‑CoV‑2, norovirus); (4) Questionnaires, where directors, teachers, and parents/guardians complete surveys about building/classroom practices and relevant health or environmental factors; and (5) Child social‑emotional development (exploratory), where teachers complete a standard checklist used in early childhood settings that describes children’s social and emotional skills (the DECA), following the program’s schedule.
What are the possible benefits and risks of participating?
Possible benefits: (1) Classrooms that receive portable filtration and/or UVGI may have improved indoor air quality, which could potentially help reduce exposure to airborne particles and germs; and (2) The study may help Head Start and other early childhood programs make informed decisions about practical, cost‑effective ways to support child health and attendance.
Possible risks/inconveniences: (1) Air cleaning units and monitors may produce some noise or require space in the classroom; (2) Upper‑room UVGI fixtures are installed and checked to meet safety guidelines so that UV exposure for children and staff remains below recommended limits; (3) Teachers, parents, and staff may spend time completing surveys and attendance logs; and (4) As with any study collecting information, there is a small risk of confidentiality breach, and the study uses secure data handling practices to reduce this risk.
Where is the study run from?
The study is coordinated by the University of Oklahoma research team and conducted in participating Head Start centers and classrooms in Oklahoma in the United States.
When is the study starting and how long is it expected to run for?
The OK‑AIR study includes two implementation cohorts. Cohort 1 is from 2023 to 2024 school year, and Cohort 2 is from 2025 to 2026 school year (with portable filtration only).
Who is funding the study?
The Oklahoma Partnership for School Readiness (OPSR) Clearinghouse award is our original sponsor to support the OK-AIR Cohort 1 study. Cohort 2 was initially supported through an EPA Children’s Environmental Health Center award, which was later terminated due to changes in agency research priorities (not due to project performance). The study team submitted an appeal, which remains under review at the time of this trial registry.
Who is the main contact?
Drs. Diane Horm and Changjie Cai from the University of Oklahoma (OU). Dr. Horm is the Founding Director of the Early Childhood Education Institute, and Professor from the College of Education at OU. Dr. Cai is the Founding Director of the Children’s Environmental Health Center in U.S. Southern Great Plains, and Associate Professor from the Hudson College of Public Health at OU.
changjie-cai@ou.edu
dhorm@ou.edu
Contact information
Principal investigator, Scientific, Public
4502 E. 41st ST., 4201-I
Tulsa
74135
United States of America
 ORCID ID |
0000-0002-1836-5329 |
|---|---|
| Phone | +1 918 660-3907 |
| dhorm@ou.edu |
Principal investigator, Scientific, Public
801 Northeast 13th Street, Room # 419
Oklahoma City
73104
United States of America
| ORCID ID |
0000-0001-5189-003X |
|---|---|
| Phone | +1 4052712070 |
| Changjie-Cai@ou.edu |
Study information
| Primary study design | Interventional |
|---|---|
| Allocation | Randomized controlled trial |
| Masking | Blinded (masking used) |
| Control | Active |
| Assignment | Factorial |
| Purpose | Device feasibility, Health services research, Prevention |
| Scientific title | OK-AIR study protocol: a longitudinal cluster-randomised 2×2 factorial trial of portable air purification and upper-room UVGI on sick-related absences, indoor air quality, environmental pathogens and social-emotional development in early care and education classrooms (birth–5 years) |
| Study acronym | OK-AIR |
| Study objectives | Primary objective: To determine whether classroom portable air purification and/or upper‑room ultraviolet germicidal irradiation (UVGI) reduce sick‑related (infectious disease–related) absence rates among children aged birth to 5 years attending Head Start early care and education (ECE) classrooms. Secondary objectives: 1. To quantify intervention effects on classroom indoor air quality (IAQ) (including particulate matter size fractions and other environmental parameters) 2. To evaluate whether interventions reduce environmental detection/burden of selected pathogens on classroom surfaces (Influenza A/B, RSV, HPIV3, SARS‑CoV‑2, Norovirus) measured by RT‑qPCR. Exploratory objectives: To examine relationships between IAQ/pathogen indicators and children’s social‑emotional development (teacher‑rated DECA) and to explore contextual moderators (e.g., ventilation practices, building conditions, household exposures) from Director/Teacher/Parent surveys; and to estimate incremental intervention costs and cost‑effectiveness (e.g., cost per sick‑related absence day averted). |
| Ethics approval(s) |
Approved 12/10/2023, The Institutional Review Board (IRB) at the University of Oklahoma (201 Stephenson Parkway, Norman, 73019, United States of America; +1 (405)325-8110; irb@ou.edu), ref: IRB#: 16282 |
| Health condition(s) or problem(s) studied | Illness‑related (infectious disease–related) absences among children (birth to 5 years) attending Head Start early care and education (ECE) classrooms; associated indoor air quality and environmental detection of respiratory/enteric viruses (Influenza A/B, RSV, HPIV3, SARS‑CoV‑2, Norovirus) in classroom environments; and children's social-emotional development. |
| Intervention | OK‑AIR is a longitudinal, pragmatic cluster‑randomised trial in Oklahoma Head Start/ECE classrooms enrolling children aged birth to 5 years. The unit of randomisation is the classroom (cluster), nested within Head Start centers. Cohort 1 (2023–2024): Within each participating center, classrooms are allocated to one of four parallel arms in a 2×2 factorial design: (1) Control (no additional intervention beyond usual center operations), (2) Portable air purification (stand‑alone units with HEPA‑class filtration; placement based on room volume and coverage; filters replaced on the recommended schedule; units secured to prevent children from switching them off), (3) Upper‑room UVGI (wall‑mounted fixtures creating an irradiated upper‑room zone; installed and commissioned to maintain occupant exposure below applicable safety limits; lamps maintained per manufacturer guidance), and (4) Combined (portable filtration + upper‑room UVGI). Cohort 2 (2025–2026): Cohort 2 was originally planned as a second factorial cohort but was amended due to funding changes; Cohort 2 retains portable filtration only. Data collection: Child attendance and absence reasons are recorded daily by classroom teachers using a standardized log. Classrooms undergo continuous IAQ monitoring (PM₁, PM₂.₅, PM₄, PM₁₀, temperature, relative humidity, CO, noise, and gas indices) across the attendance year with a seasonal monitoring framework (Winter/Spring/Summer/Fall) including designated baseline/off‑period weeks to characterize temporal and seasonal variability. Seasonal environmental surface swabs (dining tables and toilet flooring) are analyzed by RT‑qPCR for selected respiratory/enteric viruses. Contextual surveys (Director/Teacher/Parent) capture center, classroom, and household factors relevant to IAQ and child health. Children’s social‑emotional development is assessed using teacher ratings on the DECA (exploratory). A health economic evaluation will estimate intervention costs and cost‑effectiveness/cost‑benefit. |
| Intervention type | Device |
| Phase | Not Applicable |
| Drug / device / biological / vaccine name(s) | Portable air purifier and upper-room ultraviolet germicidal irradiation (UVGI) |
| Primary outcome measure(s) |
|
| Key secondary outcome measure(s) |
|
| Completion date | 31/03/2027 |
Eligibility
| Participant type(s) | |
|---|---|
| Age group | Mixed |
| Lower age limit | 0 Years |
| Upper age limit | 5 Years |
| Sex | All |
| Target sample size at registration | 480 |
| Total final enrolment | 666 |
| Key inclusion criteria | Head Start centers and classrooms: 1. Head Start centers in Oklahoma willing to participate in the OK‑AIR study 2. Classrooms able and willing to participate in study procedures, including installation/operation of assigned intervention(s) (portable filtration and/or upper‑room UVGI, where applicable), continuous indoor air quality monitoring, daily attendance and absence‑reason logging, and seasonal environmental surface sampling. Children participants: 1. Child is enrolled in a participating Head Start classroom during the study period 2. Child is within the eligible age range (birth to 5 years) at enrollment 3. Parent/guardian provides informed consent for the child’s participation and data collection (including attendance outcomes and teacher‑rated DECA, as applicable) 4. Parent/guardian provides HIPAA authorization for release of the child’s Head Start health records (where applicable/required by the study). School staff participants: Classroom teacher(s)/staff and center leadership in participating sites who agree to complete study procedures relevant to their role (e.g., attendance logs, surveys, DECA ratings). |
| Key exclusion criteria | Head Start centers and classrooms 1. Classrooms are excluded if physical constraints prevent safe/feasible installation of required intervention equipment (e.g., ceiling height or room layout constraints for upper‑room UVGI) 2. Classroom/center declines required study procedures (installation/monitoring/sampling/attendance logging). Individual participants: 1. Child is not enrolled in a participating classroom/center or outside the eligible age range 2. Parent/guardian does not provide required consent (and HIPAA authorization where applicable), such that child‑level outcomes cannot be included per study procedures. |
| Date of first enrolment | 13/10/2023 |
| Date of final enrolment | 30/09/2025 |
Locations
Countries of recruitment
- United States of America
Study participating centres
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|---|
| IPD sharing plan summary | Not expected to be made available |
| IPD sharing plan |
Editorial Notes
05/03/2026: Trial's existence confirmed by The Institutional Review Board (IRB) at the University of Oklahoma
