Adoption and Use of Air Purifiers in Households in Dhaka

Last registered on March 25, 2024
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Pre-Trial

Trial Information

General Information

Title
Adoption and Use of Air Purifiers in Households in Dhaka
RCT ID
AEARCTR-0012194
Initial registration date
September 27, 2023

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 02, 2023, 8:45 AM EDT

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

Last updated
March 25, 2024, 9:36 PM EDT

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

Locations

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Primary Investigator

Name
Martin Mattsson
Affiliation
National University of Singapore
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Other Primary Investigator(s)

PI Name
Teevrat Garg
PI Affiliation
University of California San Diego
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PI Name
Maulik Jagnani
PI Affiliation
Tufts University
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PI Name
Ashfaqul Chowdhury
PI Affiliation
International Growth Centre
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Additional Trial Information

Status
In development
Start date
2023-10-17
End date
2025-06-30
Keywords
Behavior, Environment & Energy, Health
Additional Keywords
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Air pollution is one of the most serious threats to human well-being globally and especially in urban South Asia. As air pollution levels remain high in many cities, it is important to understand what defensive investments households can make in order to reduce the damage caused by air pollution. Indoor air purifiers are one of the most widely used and promising private defensive investments to reduce air pollution’s negative impacts. However, evidence of their effects is limited and usage remains low in low- and middle-income countries where air pollution is the highest. We propose to conduct an RCT on air purifiers in households in Dhaka, Bangladesh. The project has three main objectives. First, to understand how different framings of the air pollution problem lead to different levels of interest in taking action to protect oneself and one’s family. Second, to understand the current willingness to pay for air purifiers, how it can be brought closer to market prices,as well as what determines the usage among those owning an air purifier. Third, to estimate the effects of air purifiers on health, labor supply, income, and cognition.
External Link(s)

Registration Citation

Citation
Chowdhury, Ashfaqul et al. 2024. "Adoption and Use of Air Purifiers in Households in Dhaka." AEA RCT Registry. March 25. https://doi.org/10.1257/rct.12194-2.1
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Experimental Details

Interventions

Intervention(s)
Our project has three main interventions that will be introduced sequentially: 1. We will provide households with randomly selected framings of the problem of air pollution and how air purifiers can help reduce this problem. 2. We will provide randomly selected households with air monitors. 3. We will provide randomly selected households with air purifiers.
Intervention Start Date
2023-11-28
Intervention End Date
2024-05-28

Primary Outcomes

Primary Outcomes (end points)
Response rates to invitations to register for the study, beliefs about air pollution and how harmful it is, willingness to pay for air purifiers, air purifier usage, demand for public action on air pollution, self-reported health, and health biomarkers.
Primary Outcomes (explanation)
Demand for public action on air pollution: ranking of air pollution among different issues the government should prioritize.
Self-reported health: Number of days sick, number of times visiting a doctor/hospital, total healthcare spending.
Health biomarkers: Blood pressure, lung capacity, and blood oxygen levels
A more detailed description of outcome variables will be provided in the pre-analysis plan.

Secondary Outcomes

Secondary Outcomes (end points)
A more detailed description of secondary outcome variables will be provided in the pre-analysis plan.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The project has three main objectives. First, to understand how different framings of the air pollution problem lead to different levels of interest in taking action to protect oneself and one’s family. This will be studied by randomly exposing different individuals to different types of messaging around air pollution and estimating how this affects their propensity to register their interest to receive free or discounted air monitors and air purifiers.

Second, to understand the current willingness to pay for air purifiers, how it can be brought closer to market prices, as well as what determines the usage among those owning an air purifier. We will randomly vary access to air monitors and monetary incentives (paid out at different intervals) to use these air purifiers. These interventions are designed to alleviate three commonly hypothesized reasons for why preventative health technologies are not used more widely: 1) that the direct costs are too high, 2) biased beliefs about the benefits of the technologies, and 3) present bias.

Third, we will use the random provision of air purifiers to measure the effect on health, labor supply, income, and cognition.
Experimental Design Details
Not available
Randomization Method
Simple randomization (non-stratified) is done by a tablet at the time of delivery of the air monitor and air purifier.
Randomization Unit
The randomization is done at the household. We expect there to be approximately 4 household members per household.
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
Approximately 10,000 individuals will receive an invitation to participate in the study (the framing intervention). Approximately 1,000 households will take part in the study and form the clusters for the air purifier and air monitor interventions.
Sample size: planned number of observations
10,000 invitations for the framing intervention. Approximately 1,000 households (for household-level outcomes) and 4,000 household members (for individual outcomes).
Sample size (or number of clusters) by treatment arms
Framing intervention: 1st framing 3,333 invitations to participate, 2nd framing 3,333 invitations to participate, 3rd framing 3,333 invitations to participate.

Air monitor intervention: 500 households receive air monitors, 500 households receive no air monitor.

Air purifier intervention: 350 households receive air purifiers, 650 households receive no purifier.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Institute of Health Economics, University of Dhaka
IRB Approval Date
2023-05-04
IRB Approval Number
IHE/IRB/DU/23/2023
Analysis Plan

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