Linking Outdoor and Indoor Air Pollution

Last registered on February 07, 2023


Trial Information

General Information

Linking Outdoor and Indoor Air Pollution
Initial registration date
January 30, 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
February 07, 2023, 11:10 AM EST

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



Primary Investigator

Inter-American Development Bank

Other Primary Investigator(s)

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
In Latin America, ambient air pollution is the leading environmental health risk. Ambient outdoor air quality and residential indoor air quality are linked because, while sources of indoor and outdoor air pollution differ, ambient air pollution affects indoor residential air quality. Outdoor air pollution, particularly fine particulate matter, permeates residential dwellings to become indoor air pollution, lowering residential air quality. This link between ambient air quality and residential air quality implies that improvements in ambient air quality would also lead to improvements in residential indoor air quality. Increasing awareness of the link between ambient air quality and residential air quality could increase citizens’ support for public solutions to ambient air pollution, which would reduce air pollution exposure in both the public and private spheres.
External Link(s)

Registration Citation

Hoffmann, Bridget. 2023. "Linking Outdoor and Indoor Air Pollution." AEA RCT Registry. February 07.
Experimental Details


Participants in treatment group 1 (T1) and treatment group 2 (T2) will be read a short passage with air pollution information during the survey experiment. Participants in treatment group 1 (T1) will be provided information on the level of indoor air pollution and the health impacts of indoor air pollution. Participants in treatment group 2 (T2) will be provided the same information as treatment group 1 (T1) and information on the pass-through of outdoor air pollution to residential indoor air pollution.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Willingness to contribute to tree planting; policy priorities; perception of air pollution pass-through from outdoors to indoors;
Primary Outcomes (explanation)
Willingness to contribute to tree planting is incentive compatible. Participants contribute to a tree planting NGO from their compensation for completing the survey.

Secondary Outcomes

Secondary Outcomes (end points)
Beliefs about air pollution and exposure
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Using a telephone survey, I will conduct a survey experiment in which participants are randomly assigned to a control group or one of two treatment groups. I will assess the primary hypothesis that providing participants with information on the link between outdoor and indoor air pollution will increase willingness to contribute to a tree planting fund, which will reduce ambient air pollution. During the survey, we will measure beliefs about the pass-through of outdoor to indoor air pollution before and after the information provision. In addition to the primary and secondary outcomes, we will also measure trust, altruism, and environmental preferences and awareness to explore heterogeneity in the outcomes by these characteristics.
Experimental Design Details
Randomization Method
Randomization done in office by computer stratified by cellular telephone service provider
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
2,500 individuals
Sample size: planned number of observations
2,500 individuals
Sample size (or number of clusters) by treatment arms
Approximately one-third of the participants will be assigned to the control group; approximately one-third of the participants will be assigned to treatment group 1 (T1); approximately one-third of the participants will be assigned to treatment group 2 (T2)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Innovations for Poverty Action
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

There is information in this trial unavailable to the public. Use the button below to request access.

Request Information


Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials