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Improving the Behavioural Impact of Air Quality Alerts

Improving the Behavioural Impact of Air Quality Alerts in London

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03552198
Enrollment
225
Registered
2018-06-11
Start date
2017-07-23
Completion date
2017-09-08
Last updated
2021-10-22

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Health Behavior, Pollution; Exposure

Keywords

Air quality alerts, Health behaviour change, Adherence

Brief summary

The evidence shows that adherence to air quality advice to adopt protective behaviours during pollution episodes is suboptimal, and that the traditional strategy of simply informing people about high pollution episodes is not effective. The aim of the present study was to investigate how to improve the behavioural impact of existing air quality alert messages through a systematic manipulation of key communication variables, including perceived susceptibility, self-efficacy, response efficacy, planning, message specificity, etc. Users of an existing air quality alert smartphone application in London, who agreed to take part in the study, were randomly allocated to a control group (i.e. receiving usual health advice associated with the official UK Air Quality Index) or an intervention group receiving health advice associated with air quality alerts in an alternative format (i.e. targeting key variables). Both intended and actual adherence behaviours were investigated. Qualitative data were also collected to understand the reasons for not adopting protective behaviours in response to receiving a real air pollution alert. Implications of this study include the potential to increase protective behaviours in the general population during air pollution episodes through the development of more effective communication strategies provided via existent air quality alert systems.

Detailed description

According to data released in 2014, in 2012 around 3.7 million people died prematurely in the world as a result of exposure to ambient air pollution ((WHO), 2014). Evidence has shown the negative short- and long-term effects of air pollution on both premature mortality and morbidity from cardiopulmonary disease (for an overview, see (Kelly & Fussell, 2015)). This is particularly a problem in London (Samoli et al., 2016), where levels of air pollution are quite worrying. In the UK monitoring networks measure the levels of different air pollutants, and these measurements are provided by the Department for Environment, Food & Rural Affairs (DEFRA) in the form of daily air quality indices (AQIs), together with separate health advice for at-risk groups and the general population. A recently published systematic review (D'Antoni, Smith, Auyeung, & Weinman, 2017) has found suboptimal adherence levels to health advice associated with air quality alerts, and identified several facilitators and barriers of adherence. Some of the facilitators included beliefs that air pollution can have negative health effects (i.e. perceived severity), outcome expectancies (e.g., beliefs that something can be done to reduce smog), beliefs about the health benefits of AQI adoption (i.e. response efficacy), and receiving advice from health care professionals. Barriers to adherence included: lack of understanding of the indices, being exposed to health messages that reduced both concern about air pollution and perceived susceptibility, as well as perceived lack of self-efficacy/locus of control, reliance on sensory cues and lack of time to make behavioural changes. The findings of this systematic review have informed the current research study, which aimed to improve the behavioural impact of existing air quality alerts. In particular, alternative health messages were developed based on the psychosocial factors identified in the systematic review. The purpose of the study was to test whether these theory and evidence-based alternative communication formats, compared to the official messages sent in association with the UK AQIs, maximise the behavioural impact of existing alert systems. Methods Design: This was a randomised control trail using a 2-way factorial design, with target population (2 levels: general population vs. individuals with a pre-existing health condition) and message format (2 levels: usual message format vs. alternative format) as between-factors. Qualitative data were also collected to understand the reasons for actual adherence and non-adherence. \- Theoretical framework and targeted psychosocial predictors: The COM-B model (Michie, van Stralen, & West, 2011) was used as a theoretical framework to guide in the understanding of the facilitators and barriers to behaviour change in response to air quality alerts. The control groups received usual air quality alerts and health advice based on the UK AQI messages, and the intervention groups received alternative health messages targeting knowledge about the health impact of exposure to air pollution, perceived severity of air pollution, perceived susceptibility, perceived efficacy of protective behaviours, self-efficacy, perceived negative consequences associated with protective behaviours, reliance on sensory cue, and action planning. In addition, study participants who reported having a pre-existent respiratory condition and who were randomly allocated in the intervention group, also received specific additional messages targeting beliefs about efficacy and side effects of inhalers, and medication self-efficacy. \- Targeting message specificity: Specificity refers to the extent to which a message provides a detailed description of the recommended behaviour. A meta-analysis of 18 studies (O'Keefe, 1997) found that messages providing health recommendations with a more specific description seem to be significantly more persuasive than generic recommendations (r=.10, k=18, N=11,105). Participants in the control group received the usual UK AQI message format containing less specific recommendations (e.g. advice for at risk individuals in case of high air pollution: 'Adults and children with lung problems, and adults with heart problems, should reduce strenuous physical exertion, particularly outdoors'). On the other hand, the intervention group received more specific recommendations ('Adults and children with lung problems, adults with heart problems, and older people, should reduce levels and length of physical activity outdoors. Where possible, change: travel route or exercise location (e.g. use our app to find less polluted roads or parks) or time (e.g. mornings or less polluted times)'). Control and intervention groups were compared in intended and actual behaviour change outcome measures. We predicted that the alternative format would be associated with higher behaviour change, compared to the usual format.

Interventions

BEHAVIORALAlternative health advice

These messages targeted specific beliefs about air pollution and protective actions aimed at reducing exposure to air pollution. In addition, message specificity was targeted, which means that compared to the usual messages, the alternative messages reported more detailed health recommendations.

Sponsors

National Institute for Health Research, United Kingdom
CollaboratorOTHER_GOV
Public Health England
CollaboratorOTHER_GOV
King's College London
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
PREVENTION
Masking
SINGLE (Subject)

Masking description

To avoid bias participants were not told how the wording of the health advice had been changed.

Intervention model description

This was a randomised control trail using a 2-way factorial design, with target population (2 levels: general population vs. individuals with a pre-existing health condition) and message format (2 levels: usual message format vs. alternative format) as between-factors.

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes

Inclusion criteria

* To be eligible to participate, participants had to be members of the general public in the adult age range (\>18 years), be fluent in English, working or living in Greater London, and being new or old users of a specific air quality alert smartphone application.

Exclusion criteria

* younger than 18 years * not working or living in Greater London * no longer users of the air quality alert smartphone application.

Design outcomes

Primary

MeasureTime frameDescription
Adoption of Protective Behaviour at 4 WeeksBaseline and at 4 weeksDifferences between conditions in actual adoption of protective behaviours at 4 weeks. Outcome measures were collected via self-reports: The question was: 'In the past 4 weeks, how often have you taken action to reduce exposure to air pollution, in response to hearing or reading an air quality forecast?' Measures: from 1 'Not at all' to 9 'all of the time' (answers 'N/A, I am not aware of any forecast' were excluded from analyses).

Secondary

MeasureTime frameDescription
Considered Making Permanent Changesat 4 weeksDifferences between conditions in planning the adoption of protective behaviours at 4 weeks. Outcome measures were collected via self-reports: The question was: 'In the past 4 weeks, have you considered making permanent changes to daily travel route or exercise location/time?' possible answers were 'yes' or 'no'. 'unsure' answers were treated as system missing.
Actual Behaviour Change in Response to a Real Air Quality AlertAt 3 weeksDifferences between conditions in self-reported actual behaviour change in response to receiving a real air quality alert. Behavioural outcomes were collected via a questionnaire asking participants to respond 'yes/no' to whether they had changed a series of behaviours in response to receiving the alert. In this case it was a 'moderate' alert
Intentions to Adhere to Health Advice Associated With a Hypothetical High Air Pollution ScenarioBaseline and at 4 weeksDifferences between conditions in intentions to adhere to the health advice received in association with a hypothetical high air pollution alert scenario. Intentions were measured by a self-report item: participants were asked to agree with a statement about their adherence intentions on 9-point scale, where 1=strongly disagree to 9=strongly agree.

Countries

United Kingdom

Participant flow

Recruitment details

Eligible participants had to be members of the general public in the adult age range (\> 18 years), be fluent in English, working or living in Greater London (as this is the geographical area that CityAir covers), and being new or existing users of the City Air smartphone application.

Pre-assignment details

Of the 238 initially submitted questionnaires, 13 (5.5%) were incomplete, leaving a total of 225 complete initial questionnaires.

Participants by arm

ArmCount
General Public/Usual Health Advice
Healthy participants with a self-reported existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
34
General Public/Alternative Health Advice
Generally healthy participants were randomised to receive targeted health advice about the adoption of protective behaviours in an alternative format. Alternative health advice: These messages targeted specific beliefs about air pollution and protective actions aimed at reducing exposure to air pollution. In addition, message specificity was targeted, which means that compared to the usual messages, the alternative messages reported more detailed health recommendations.
29
At Risk Group/Usual Health Advice
Participants with a self-reported pre-existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
7
At Risk Group/Alternative Health Advice
Participants with a self-reported existing health conditions were randomised to receive targeted health advice (based on their health condition) about the adoption of protective behaviours in an alternative format. Alternative health advice: These messages targeted specific beliefs about air pollution and protective actions aimed at reducing exposure to air pollution. In addition, message specificity was targeted, which means that compared to the usual messages, the alternative messages reported more detailed health recommendations.
12
Total82

Withdrawals & dropouts

PeriodReasonFG000FG001FG002FG003
Overall StudyDid not receive air alerts1001
Overall StudyIncomplete/unmatched questionnaire6722
Overall StudyLost to Follow-up42481519

Baseline characteristics

CharacteristicGeneral Public/Usual Health AdviceGeneral Public/Alternative Health AdviceAt Risk Group/Usual Health AdviceAt Risk Group/Alternative Health AdviceTotal
Adoption of protective behaviour at baseline3.00 units on a scale
STANDARD_DEVIATION 0.45
2.38 units on a scale
STANDARD_DEVIATION 0.45
3.43 units on a scale
STANDARD_DEVIATION 1.42
2.83 units on a scale
STANDARD_DEVIATION 0.9
2.79 units on a scale
STANDARD_DEVIATION 0.3
Age, Customized
Age Range
18-24 years
0 Participants2 Participants0 Participants0 Participants2 Participants
Age, Customized
Age Range
25-34 years
12 Participants12 Participants1 Participants5 Participants30 Participants
Age, Customized
Age Range
35-49 years
17 Participants11 Participants1 Participants3 Participants32 Participants
Age, Customized
Age Range
50+ years
5 Participants4 Participants5 Participants4 Participants18 Participants
Race/Ethnicity, Customized
Ethnicity
Other
3 Participants2 Participants1 Participants2 Participants8 Participants
Race/Ethnicity, Customized
Ethnicity
White
31 Participants27 Participants6 Participants10 Participants74 Participants
Sex: Female, Male
Female
13 Participants11 Participants2 Participants5 Participants31 Participants
Sex: Female, Male
Male
21 Participants18 Participants5 Participants7 Participants51 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
EG003
affected / at risk
deaths
Total, all-cause mortality
0 / 00 / 00 / 00 / 0
other
Total, other adverse events
0 / 00 / 00 / 00 / 0
serious
Total, serious adverse events
0 / 00 / 00 / 00 / 0

Outcome results

Primary

Adoption of Protective Behaviour at 4 Weeks

Differences between conditions in actual adoption of protective behaviours at 4 weeks. Outcome measures were collected via self-reports: The question was: 'In the past 4 weeks, how often have you taken action to reduce exposure to air pollution, in response to hearing or reading an air quality forecast?' Measures: from 1 'Not at all' to 9 'all of the time' (answers 'N/A, I am not aware of any forecast' were excluded from analyses).

Time frame: Baseline and at 4 weeks

Population: ANCOVA (analysis of covariance) was performed for actual behaviour change at four weeks, adjusting for baseline data collected about one month earlier (target population and intervention/ control group were entered as fixed factors).

ArmMeasureValue (MEAN)Dispersion
General Public/Usual Health AdviceAdoption of Protective Behaviour at 4 Weeks3.67 units on a scale 1-9Standard Deviation 0.44
General Public/Alternative Health AdviceAdoption of Protective Behaviour at 4 Weeks4.25 units on a scale 1-9Standard Deviation 0.48
At Risk Group/Usual Health AdviceAdoption of Protective Behaviour at 4 Weeks4.29 units on a scale 1-9Standard Deviation 0.97
At Risk Group/Alternative Health AdviceAdoption of Protective Behaviour at 4 Weeks3.65 units on a scale 1-9Standard Deviation 0.74
Comparison: We predicted that the groups receiving the alternative format of air quality notifications would report greater frequency of behaviour change at 4 weeks compared to the groups receiving the usual format.p-value: 0.964ANCOVA
Secondary

Actual Behaviour Change in Response to a Real Air Quality Alert

Differences between conditions in self-reported actual behaviour change in response to receiving a real air quality alert. Behavioural outcomes were collected via a questionnaire asking participants to respond 'yes/no' to whether they had changed a series of behaviours in response to receiving the alert. In this case it was a 'moderate' alert

Time frame: At 3 weeks

Population: Chi square tests were performed to analyse differences in proportion of self-reported actual behaviour change between groups, in relation to a real moderate air pollution episode. 'Unsure' answers in relation to actual behaviour change were treated as system missing and excluded from analyses.

ArmMeasureGroupCategoryValue (COUNT_OF_PARTICIPANTS)
General Public/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel routeYes4 Participants
General Public/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise locationNo15 Participants
General Public/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel timeYes0 Participants
General Public/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel routeNo15 Participants
General Public/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise locationYes2 Participants
General Public/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise timeNo16 Participants
General Public/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged level/length of physical activity outdoorsNo16 Participants
General Public/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged level/length of physical activity outdoorsYes3 Participants
General Public/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise timeYes2 Participants
General Public/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel timeNo19 Participants
General Public/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel routeNo23 Participants
General Public/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged level/length of physical activity outdoorsYes2 Participants
General Public/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged level/length of physical activity outdoorsNo23 Participants
General Public/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel routeYes2 Participants
General Public/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel timeYes3 Participants
General Public/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel timeNo22 Participants
General Public/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise timeYes5 Participants
General Public/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise timeNo19 Participants
General Public/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise locationYes6 Participants
General Public/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise locationNo18 Participants
At Risk Group/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise timeNo5 Participants
At Risk Group/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise timeYes2 Participants
At Risk Group/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged level/length of physical activity outdoorsYes2 Participants
At Risk Group/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise locationNo5 Participants
At Risk Group/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel timeNo6 Participants
At Risk Group/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged level/length of physical activity outdoorsNo4 Participants
At Risk Group/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel routeYes1 Participants
At Risk Group/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise locationYes2 Participants
At Risk Group/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel timeYes1 Participants
At Risk Group/Usual Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel routeNo6 Participants
At Risk Group/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel timeYes2 Participants
At Risk Group/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise locationYes1 Participants
At Risk Group/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel timeNo9 Participants
At Risk Group/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise timeYes1 Participants
At Risk Group/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged level/length of physical activity outdoorsYes5 Participants
At Risk Group/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise locationNo10 Participants
At Risk Group/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged exercise timeNo11 Participants
At Risk Group/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel routeYes4 Participants
At Risk Group/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged travel routeNo7 Participants
At Risk Group/Alternative Health AdviceActual Behaviour Change in Response to a Real Air Quality AlertChanged level/length of physical activity outdoorsNo7 Participants
Comparison: We predicted that the alternative health advice would lead to greater actual behaviour change compared to the usual formatp-value: >0.05Fisher Exact
Secondary

Considered Making Permanent Changes

Differences between conditions in planning the adoption of protective behaviours at 4 weeks. Outcome measures were collected via self-reports: The question was: 'In the past 4 weeks, have you considered making permanent changes to daily travel route or exercise location/time?' possible answers were 'yes' or 'no'. 'unsure' answers were treated as system missing.

Time frame: at 4 weeks

Population: A Chi square test was performed to analyse whether there were significant differences in the proportion of respondents who had considered making permanent changes to their daily travel route, exercise location or exercise time between groups.

ArmMeasureCategoryValue (COUNT_OF_PARTICIPANTS)
General Public/Usual Health AdviceConsidered Making Permanent Changesyes10 Participants
General Public/Usual Health AdviceConsidered Making Permanent Changesno23 Participants
General Public/Alternative Health AdviceConsidered Making Permanent Changesno12 Participants
General Public/Alternative Health AdviceConsidered Making Permanent Changesyes14 Participants
At Risk Group/Usual Health AdviceConsidered Making Permanent Changesyes3 Participants
At Risk Group/Usual Health AdviceConsidered Making Permanent Changesno4 Participants
At Risk Group/Alternative Health AdviceConsidered Making Permanent Changesyes7 Participants
At Risk Group/Alternative Health AdviceConsidered Making Permanent Changesno5 Participants
Comparison: We predicted that more respondents in the intervention groups (i.e. receiving alternative health advice) would consider making permanent changes to their daily travel route, exercise location or exercise time compared to the control groupsp-value: 0.043Chi-squared
Secondary

Intentions to Adhere to Health Advice Associated With a Hypothetical High Air Pollution Scenario

Differences between conditions in intentions to adhere to the health advice received in association with a hypothetical high air pollution alert scenario. Intentions were measured by a self-report item: participants were asked to agree with a statement about their adherence intentions on 9-point scale, where 1=strongly disagree to 9=strongly agree.

Time frame: Baseline and at 4 weeks

Population: ANCOVA (analysis of covariance) was performed for behavioural intentions in relation to the high air pollution hypothetical scenario at four weeks, adjusting for baseline data collected about one month earlier (target population and intervention/control group were entered as fixed factors).

ArmMeasureValue (MEAN)Dispersion
General Public/Usual Health AdviceIntentions to Adhere to Health Advice Associated With a Hypothetical High Air Pollution Scenario6.69 score on a scaleStandard Error 0.23
General Public/Alternative Health AdviceIntentions to Adhere to Health Advice Associated With a Hypothetical High Air Pollution Scenario6.26 score on a scaleStandard Error 0.33
At Risk Group/Usual Health AdviceIntentions to Adhere to Health Advice Associated With a Hypothetical High Air Pollution Scenario7.58 score on a scaleStandard Error 0.28
At Risk Group/Alternative Health AdviceIntentions to Adhere to Health Advice Associated With a Hypothetical High Air Pollution Scenario6.93 score on a scaleStandard Error 0.5
Comparison: We predicted that the alternative format would lead to stronger intentions to adhere to recommendations associated with an hypothetical high air pollution episode compared to the usual format.p-value: >0.05ANCOVA

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026