Effect of Air Pollution on the Cognitive Function of Adolescents

Study Overview
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Brief Summary
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Previous observational studies have reported an association between higher air pollution exposure and lower attention in children. With this project, the investigators aim to confirm this association in adolescents using an experimental design. In addition, the study will assess the relationship between air pollution exposure and individual preferences with respect to risk, time and social considerations. High school students in 3rd grade (ESO, 14-15 years of age) in different high schools in the Barcelona province (Spain) will be invited to participate. For each class in each high school, participating students will be randomly split into two equal-sized groups. Each group will be assigned to a different classroom where they will complete several activities during two hours, including an attention test (Flanker task) and a reduced version of the Global Preferences Survey. One of the classrooms will have an air purifier that will clean the air. The other classroom will have the same device but without the filters, so it will only re-circulate the air without cleaning it. Students will be masked to intervention allocation. The investigators hypothesize that students assigned to the clean air classroom will have better scores in the attention test, and that decision-making will also present differences in the two classrooms.

Official Title
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Citizen Science for Analysing the Effect of Air Pollution on the Cognitive Function of Adolescents

Conditions
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Attention Impaired, Risk-Taking, Risk Behavior, Social Preferences, Decision Making, Attention

Intervention / Treatment
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* Other: Purifying the air with a Pure Airbox device (Zonair 3D)
* Other: Using a sham air purifier (same device without filters)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Students in the 3rd ESO course in participating high schools with signed informed consent Exclusion Criteria: None

Ages Eligible for Study
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Minimum Age: 13 Years
Maximum Age: 16 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Purified air<br>Purifying the air with a Pure Airbox device (Zonair 3D). Use of air purifier (Pure Airbox, Zonair 3D) in the classroom 30 minutes before the participants enter the room and during the 2 hours of the experiment. | Other: Purifying the air with a Pure Airbox device (Zonair 3D)<br>* Purifying the air of the classroom where the experiment is conducted using a Pure Airbox device (Zonair 3D)<br>* Other names: Air cleaning;|
| Sham Comparator: Normal air<br>Using a sham air purifier (same device without filters). Use of the same air purifier but without filters, so that it only recirculates the air without purifying it. Used for the same time period than the other arm. | Other: Using a sham air purifier (same device without filters)<br>* Use the air purifier (Pure Airbox, Zonair 3D) without filters in the classroom where the experiment is conducted<br>* Other names: Sham air cleaner;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Response speed consistency throughout the Attention Network Task-Flanker Task (post ANT) | Calculated as hit reaction time standard error for correct responses (HRT-SE). A higher HRT-SE indicates highly variable reactions related to inattentiveness | Obtained from a test administered approximately 90 minutes after entering the classroom | 
| Combined risk taking score | Risk taking = 0.4729985 × Risk preference score + 0.5270015 × Willingness to take risks, that follows the parameters of Falk et al (2018), where the Risk preference score is the final node in the risk tree (see the online appendix of Falk et al (2018)), which is a value between 1 and 32, ranked by the level of risk aversion, and the Willingness to take risks refers to the answer to the question on one's willingness to take risks. | Obtained from a test administered approximately 100 minutes after entering the classroom | 
| Combined patience score | Patience = 0.7115185 × Time preference score + 0.2884815 × Self assessment of patience, that follows the parameters of Falk et al (2018), where the Time preference score is the final node in the time tree (see the online appendix of Falk et al (2018)), which is a value between 1 and 32, ranked by the level of patience, and the Self assessment of patience refers to the answer to the question on the self-assessment of patience (willingness to give up something today). | Obtained from a test administered approximately 100 minutes after entering the classroom | 
| Positive reciprocity score | Positive reciprocity = 0.4847038 × Willingness to return favor + 0.5152962 × Size of gift, that follows the parameters of Falk et al (2018), where Willingness to return favor refers to the answer to the question on the willingness to return a favor, and Size of gift refers to the answer to the question on the reported size of the gift that would return to a stranger. | Obtained from a test administered approximately 100 minutes after entering the classroom | 
| Altruism score | Altruism = 0.6350048 × Willingness to give to good causes + 0.3649952 × Hypothetical donation, that follows the parameters of Falk et al (2018), where Willingness to give to good causes refers to the answer to the question on the willingness to give to good causes, and Hypothetical donation refers to the answer to the question on the size of the hypothetical donation one would be willing to make. | Obtained from a test administered approximately 100 minutes after entering the classroom | 
| Trust score | Answer to the question I assume that people have only the best intentions. | Obtained from a test administered approximately 100 minutes after entering the classroom | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Impulsivity (from ANT) | Number of incorrect responses (responses made in the opposite direction to the direction of the target arrow) | Obtained from a test administered approximately 90 minutes after entering the classroom | 
| Selective attention (from ANT) | Number of omission errors (failure to respond) | Obtained from a test administered approximately 90 minutes after entering the classroom | 
| Alerting score (from ANT) | Subtracting the median RT for double cue from median RT for the no cue condition (calculations performed after removing the incongruent trials) | Obtained from a test administered approximately 90 minutes after entering the classroom | 
| Orienting score (from ANT) | Subtracting the median RT for spatial cue from the RT for central cue (calculations performed after removing the incongruent trials) | Obtained from a test administered approximately 90 minutes after entering the classroom | 
| Conflict score (executive attention) (from ANT) | Participant's median RT for each flanker condition (across cue conditions) and subtracted the congruent from the incongruent RTs | Obtained from a test administered approximately 90 minutes after entering the classroom | 
| Self assessment of how good they are in math | Answer to the question on how good they are in math. | Obtained from a test administered approximately 100 minutes after entering the classroom | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Attention, Air pollution, Black carbon, Particulate matter, Risk behavior, Social preferences, Decision making, Air purifier, Air cleaner