Clean Air in the Classroom: Environmental Inputs and Human Capital Formation

Last registered on January 29, 2026
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Pre-Trial

Trial Information

General Information

Title
Clean Air in the Classroom: Environmental Inputs and Human Capital Formation
RCT ID
AEARCTR-0012772
Initial registration date
January 08, 2024

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
January 09, 2024, 1:16 PM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
January 29, 2026, 5:40 AM EST

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Country
Pakistan
Region

Primary Investigator

Name
Samreen Malik
Affiliation
New York University (AD)
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Other Primary Investigator(s)

PI Name
Torsten Figueiredo Walter
PI Affiliation
New York University (AD)
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PI Name
Talha Naeem
PI Affiliation
University of British Columbia
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PI Name
Nitin Kumar Bharti
PI Affiliation
New York University (AD)
Contact Investigator
PI Name
David Blakeslee
PI Affiliation
New York University (AD)
Contact Investigator

Additional Trial Information

Status
Completed
Start date
2023-08-01
End date
2024-08-31
Keywords
Education, Environment & Energy, Health
Additional Keywords
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Poor air quality has become endemic in many parts of the world due to its negative impact on health and cognitive abilities, with several developing countries shutting down their education and economic activities for weeks when air quality is bad. Early exposure to bad air quality is linked with serious health impacts that could limit one's potential (Prunicki et al., 2021), making young children particularly vulnerable. While improving outdoor air quality is costly and requires collective action from numerous stakeholders, improving indoor air pollution (IAP) may not only aid in mitigating some of the negative impacts of exposure to bad air quality but also serve as a relatively cheap and feasible policy alternative to shutting down education and economic activities. Our understanding of the efficacy of improving IAP is limited. To that end, we are currently running a randomized field experiment in a private school network in and around Lahore -- one of the most polluted cities in Pakistan -- through which we provide randomly selected schools in the network with air purifiers and monitors to investigate whether improved IAP impacts young children's health, cognitive, and non-cognitive outcomes and how those effects change with cumulative exposure.
External Link(s)

Registration Citation

Citation
Bharti, Nitin Kumar et al. 2026. "Clean Air in the Classroom: Environmental Inputs and Human Capital Formation." AEA RCT Registry. January 29. https://doi.org/10.1257/rct.12772-1.1
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
We assigned schools to air purifier treatment, i.e., the schools randomly assigned to the treatment status receive an air purifier. We also place air monitors in treatment and control schools to track air quality.
Intervention (Hidden)
We assigned schools to air purifier treatment, i.e., the schools randomly assigned to the treatment status receive an air purifier. The air purifier is placed in the grade-2 classroom, and in the case of a school with multiple sections, a random section is drawn to receive the air purifier. The treatment school/classroom also gets an air monitor, which tracks air quality. Due to the limited stock of air monitors, we also place air monitors in a randomly selected subset of control schools.
Intervention Start Date
2023-11-09
Intervention End Date
2024-03-31

Primary Outcomes

Primary Outcomes (end points)
1. Air Quality
2. Test Scores
Primary Outcomes (explanation)
1. Air Quality: We use air monitoring devices to quantify the variations in air quality resulting from our intervention. These monitoring instruments directly capture and record data concerning the concentration of particulate matter present in the air.

Secondary Outcomes

Secondary Outcomes (end points)
1. Disaggregated measures of test scores capturing different aspects of learning and performance
2. Cognitive endurance
3. Non-cognitive outcomes: moral judgement, absenteeism, classroom behavior
4. Adaptation
5. Physical and mental health, including chronic and short-term health problems, sleeping pattern, and happiness.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We adopted a stratified randomization design, assigning 132 schools to treatment and control within each stratum. The strata are based on a combination of three variables: location (whether the school is located inside or outside the ring road), school size (whether the school is a single or multi-section school) and batch (total of four batches) in which we received the up-to-date data on the school from our first visit. Within each batch (except the last batch), we divide the schools into four types: inside ring road and single section, inside ring road and multi-section, outside ring road and single section, inside ring road and multi-section. In the last batch, since there were only eight schools (all outside the ring road and only one multi-section), we formed it into one stratum. In total, there are 13 strata.

We assigned 60 schools to the treatment group and 72 to the control group. Within multi-section schools, we randomly select a section where equipment is installed. The treatment schools (or the randomly selected section if the school is multi-section) are provided with an air purifier and an air quality monitor. In control schools, we randomly selected 44 schools (out of 72) to receive air quality monitors due to the limited stock of air monitors.
Experimental Design Details
We adopted a stratified randomization design, assigning 132 schools to treatment and control within each stratum. The strata are based on a combination of three variables: location (whether the school is located inside or outside the ring road), school size (whether the school is a single or multi-section school) and batch (total of four batches) in which we received the up-to-date data on the school from our first visit. Within each batch (except the last batch), we divide the schools into four types: inside ring road and single section, inside ring road and multi-section, outside ring road and single section, inside ring road and multi-section. In the last batch, since there were only eight schools (all outside the ring road and only one multi-section), we formed it into one stratum. In total, there are 13 strata.

We assigned 60 schools to the treatment group and 72 to the control group. Within multi-section schools, we randomly select a section where equipment is installed. The treatment schools (or the randomly selected section if the school is multi-section) are provided with an air purifier and an air quality monitor. In control schools, we randomly selected 44 schools (out of 72) to receive air quality monitors due to the limited stock of air monitors.
Randomization Method
Stratified randomization is done in the office by a computer.
Randomization Unit
Section/School
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
132 section/school.
Sample size: planned number of observations
Approximately 4500 students (~2000 in treatment and ~2500 in control)
Sample size (or number of clusters) by treatment arms
60 section/schools with air purifier treatment
72 section/schools in the control group
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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IRB

Institutional Review Boards (IRBs)

IRB Name
New York University Abu Dhabi Institutional Review Board
IRB Approval Date
2023-10-11
IRB Approval Number
HRPP-2023-71
Analysis Plan

Analysis Plan Documents

Clean Air - Pre-Analysis Plan - January 2024

MD5: 539c311d53522d570c16df0d4dfc46a9

SHA1: 74c23b470723690f4a3a710641753015af19c5c3

Uploaded At: January 06, 2024

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials