Air purifiers and workplace productivity

Last registered on July 31, 2023

Pre-Trial

Trial Information

General Information

Title
Air purifiers and workplace productivity
RCT ID
AEARCTR-0010161
Initial registration date
October 13, 2022

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
October 17, 2022, 5:23 PM EDT

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

Last updated
July 31, 2023, 11:36 PM EDT

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

Locations

Region

Primary Investigator

Affiliation
Harvard University

Other Primary Investigator(s)

Additional Trial Information

Status
On going
Start date
2022-09-20
End date
2023-09-30
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Air quality conditions are alarmingly poor in many developing countries. Many parts of India face grave levels of air pollution with conditions ranging from unhealthy to hazardous on most days. Decreased worker productivity due to elevated concentration of particulate matter has been documented in several contexts. White-collar workers spend most of their day indoors, and air purifiers are effective at improving indoor air quality even in high pollution settings by removing around 90% of particulate matter.

I am partnering with a call center in Haryana, India to run an impact evaluation of air purifier use. Workers at the call center sit on two floors, and the treatment is randomized at the floor-day level with one treated and one control floor each day. The study aims to address the following questions: (1) What is the short term impact of reducing indoor particulate pollutants on worker health, cognition and productivity? (2) What is the heterogeneity in individual sensitivity to indoor pollution?
External Link(s)

Registration Citation

Citation
Bangia, Sachet. 2023. "Air purifiers and workplace productivity." AEA RCT Registry. July 31. https://doi.org/10.1257/rct.10161-1.3
Experimental Details

Interventions

Intervention(s)
Air purifiers with HEPA filters that are effective at reducing particulate pollution indoors even in settings with extremely high outdoor pollution.
Intervention Start Date
2022-10-13
Intervention End Date
2023-02-05

Primary Outcomes

Primary Outcomes (end points)
Worker productivity
Primary Outcomes (explanation)
Worker productivity is closely tracked by the firm and this data will be made available to the researcher for analysis. The specific metrics that are relevant depend on the type of worker. There are 4 lines of business included in the study and each has its own performance metrics. The metrics capture both the volume of the work done (eg. number of calls received or made, number of customer support tickets closed) and quality of the work (eg. customer satisfaction ratings, quality audit checks etc.). I will construct one or two productivity indices using these metrics.

Secondary Outcomes

Secondary Outcomes (end points)
(1) Worker physical health and cognition
(2) Indoor air quality
Secondary Outcomes (explanation)
Worker health variables include measures of physical health collected by surveyors (heart rate, blood pressure, blood oxygen, measures of lung functioning, 1-minute handheld ECG reading for Heart Rate Variability) and self-reported symptoms, self assessed mood, fatigue, and ability to concentrate. Cognitive functioning is measured through computer games that test for attention, memory and inhibitory control. These outcomes will be collected one to two times per week for each participant.

Air quality monitors will continuously track PM10 and PM2.5 on both floors of the call center. This will be used to establish the first stage effect of the intervention.

Experimental Design

Experimental Design
Treatment assignment will occur at a floor-day level, with one treated and one control floor each day.
Experimental Design Details
On days that a floor is treated, the air purifiers installed on that floor will operate normally. On days that a floor is the control, the HEPA filters will be removed from all air purifiers on that floor so they will operate as "sham" air purifiers.
Randomization Method
Using randtreat in stata, stratified by week.
Randomization Unit
Floor-day
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
160 floor-days
Sample size: planned number of observations
Around 120 employees on the two floors observed for 80 days.
Sample size (or number of clusters) by treatment arms
80 floor-days in control, 80-floor days in treatment
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Using data from the same time period in the previous year to simulate power suggests a MDES on productivity metrics between 0.15-0.2 SD units (depending on the inherent variability in the metric), when the productivity is aggregated at the daily level. Using variation in air quality during the work shift along with the productivity will yield even more power for metrics that can be analyzed at a lower level of aggregation than the full day.
IRB

Institutional Review Boards (IRBs)

IRB Name
Harvard University Area IRB
IRB Approval Date
2022-08-29
IRB Approval Number
N/A
IRB Name
Institute for Financial Management and Research
IRB Approval Date
2022-09-08
IRB Approval Number
N/A
Analysis Plan

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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