Trial Outcomes & Findings for Improving the Behavioural Impact of Air Quality Alerts (NCT NCT03552198)
NCT ID: NCT03552198
Last Updated: 2021-10-22
Results Overview
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).
Recruitment status
COMPLETED
Study phase
NA
Target enrollment
225 participants
Primary outcome timeframe
Baseline and at 4 weeks
Results posted on
2021-10-22
Participant Flow
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.
Of the 238 initially submitted questionnaires, 13 (5.5%) were incomplete, leaving a total of 225 complete initial questionnaires.
Participant milestones
| Measure |
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.
|
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.
|
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.
|
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.
|
|---|---|---|---|---|
|
Overall Study
STARTED
|
83
|
84
|
24
|
34
|
|
Overall Study
Final Questionnaire 4 Weeks Follow-up
|
34
|
29
|
7
|
12
|
|
Overall Study
COMPLETED
|
34
|
29
|
7
|
12
|
|
Overall Study
NOT COMPLETED
|
49
|
55
|
17
|
22
|
Reasons for withdrawal
| Measure |
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.
|
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.
|
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.
|
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.
|
|---|---|---|---|---|
|
Overall Study
Lost to Follow-up
|
42
|
48
|
15
|
19
|
|
Overall Study
Incomplete/unmatched questionnaire
|
6
|
7
|
2
|
2
|
|
Overall Study
Did not receive air alerts
|
1
|
0
|
0
|
1
|
Baseline Characteristics
Improving the Behavioural Impact of Air Quality Alerts
Baseline characteristics by cohort
| Measure |
General Public/Usual Health Advice
n=34 Participants
Healthy participants with a self-reported existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
|
General Public/Alternative Health Advice
n=29 Participants
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.
|
At Risk Group/Usual Health Advice
n=7 Participants
Participants with a self-reported pre-existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
|
At Risk Group/Alternative Health Advice
n=12 Participants
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.
|
Total
n=82 Participants
Total of all reporting groups
|
|---|---|---|---|---|---|
|
Age, Customized
Age Range · 18-24 years
|
0 Participants
n=5 Participants
|
2 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
0 Participants
n=4 Participants
|
2 Participants
n=21 Participants
|
|
Age, Customized
Age Range · 25-34 years
|
12 Participants
n=5 Participants
|
12 Participants
n=7 Participants
|
1 Participants
n=5 Participants
|
5 Participants
n=4 Participants
|
30 Participants
n=21 Participants
|
|
Age, Customized
Age Range · 35-49 years
|
17 Participants
n=5 Participants
|
11 Participants
n=7 Participants
|
1 Participants
n=5 Participants
|
3 Participants
n=4 Participants
|
32 Participants
n=21 Participants
|
|
Age, Customized
Age Range · 50+ years
|
5 Participants
n=5 Participants
|
4 Participants
n=7 Participants
|
5 Participants
n=5 Participants
|
4 Participants
n=4 Participants
|
18 Participants
n=21 Participants
|
|
Sex: Female, Male
Female
|
13 Participants
n=5 Participants
|
11 Participants
n=7 Participants
|
2 Participants
n=5 Participants
|
5 Participants
n=4 Participants
|
31 Participants
n=21 Participants
|
|
Sex: Female, Male
Male
|
21 Participants
n=5 Participants
|
18 Participants
n=7 Participants
|
5 Participants
n=5 Participants
|
7 Participants
n=4 Participants
|
51 Participants
n=21 Participants
|
|
Race/Ethnicity, Customized
Ethnicity · White
|
31 Participants
n=5 Participants
|
27 Participants
n=7 Participants
|
6 Participants
n=5 Participants
|
10 Participants
n=4 Participants
|
74 Participants
n=21 Participants
|
|
Race/Ethnicity, Customized
Ethnicity · Other
|
3 Participants
n=5 Participants
|
2 Participants
n=7 Participants
|
1 Participants
n=5 Participants
|
2 Participants
n=4 Participants
|
8 Participants
n=21 Participants
|
|
Adoption of protective behaviour at baseline
|
3.00 units on a scale
STANDARD_DEVIATION 0.45 • n=5 Participants
|
2.38 units on a scale
STANDARD_DEVIATION 0.45 • n=7 Participants
|
3.43 units on a scale
STANDARD_DEVIATION 1.42 • n=5 Participants
|
2.83 units on a scale
STANDARD_DEVIATION 0.90 • n=4 Participants
|
2.79 units on a scale
STANDARD_DEVIATION 0.30 • n=21 Participants
|
PRIMARY outcome
Timeframe: Baseline and at 4 weeksPopulation: 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).
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).
Outcome measures
| Measure |
General Public/Usual Health Advice
n=34 Participants
Healthy participants with a self-reported existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
|
General Public/Alternative Health Advice
n=29 Participants
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.
|
At Risk Group/Usual Health Advice
n=7 Participants
Participants with a self-reported pre-existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
|
At Risk Group/Alternative Health Advice
n=12 Participants
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.
|
|---|---|---|---|---|
|
Adoption of Protective Behaviour at 4 Weeks
|
3.67 units on a scale 1-9
Standard Deviation 0.44
|
4.25 units on a scale 1-9
Standard Deviation 0.48
|
4.29 units on a scale 1-9
Standard Deviation 0.97
|
3.65 units on a scale 1-9
Standard Deviation 0.74
|
SECONDARY outcome
Timeframe: at 4 weeksPopulation: 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.
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.
Outcome measures
| Measure |
General Public/Usual Health Advice
n=33 Participants
Healthy participants with a self-reported existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
|
General Public/Alternative Health Advice
n=26 Participants
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.
|
At Risk Group/Usual Health Advice
n=7 Participants
Participants with a self-reported pre-existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
|
At Risk Group/Alternative Health Advice
n=12 Participants
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.
|
|---|---|---|---|---|
|
Considered Making Permanent Changes
yes
|
10 Participants
|
14 Participants
|
3 Participants
|
7 Participants
|
|
Considered Making Permanent Changes
no
|
23 Participants
|
12 Participants
|
4 Participants
|
5 Participants
|
SECONDARY outcome
Timeframe: At 3 weeksPopulation: 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.
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
Outcome measures
| Measure |
General Public/Usual Health Advice
n=19 Participants
Healthy participants with a self-reported existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
|
General Public/Alternative Health Advice
n=25 Participants
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.
|
At Risk Group/Usual Health Advice
n=7 Participants
Participants with a self-reported pre-existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
|
At Risk Group/Alternative Health Advice
n=12 Participants
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.
|
|---|---|---|---|---|
|
Actual Behaviour Change in Response to a Real Air Quality Alert
Changed level/length of physical activity outdoors · Yes
|
3 Participants
|
2 Participants
|
2 Participants
|
5 Participants
|
|
Actual Behaviour Change in Response to a Real Air Quality Alert
Changed level/length of physical activity outdoors · No
|
16 Participants
|
23 Participants
|
4 Participants
|
7 Participants
|
|
Actual Behaviour Change in Response to a Real Air Quality Alert
Changed travel route · Yes
|
4 Participants
|
2 Participants
|
1 Participants
|
4 Participants
|
|
Actual Behaviour Change in Response to a Real Air Quality Alert
Changed travel route · No
|
15 Participants
|
23 Participants
|
6 Participants
|
7 Participants
|
|
Actual Behaviour Change in Response to a Real Air Quality Alert
Changed travel time · Yes
|
0 Participants
|
3 Participants
|
1 Participants
|
2 Participants
|
|
Actual Behaviour Change in Response to a Real Air Quality Alert
Changed travel time · No
|
19 Participants
|
22 Participants
|
6 Participants
|
9 Participants
|
|
Actual Behaviour Change in Response to a Real Air Quality Alert
Changed exercise time · Yes
|
2 Participants
|
5 Participants
|
2 Participants
|
1 Participants
|
|
Actual Behaviour Change in Response to a Real Air Quality Alert
Changed exercise time · No
|
16 Participants
|
19 Participants
|
5 Participants
|
11 Participants
|
|
Actual Behaviour Change in Response to a Real Air Quality Alert
Changed exercise location · Yes
|
2 Participants
|
6 Participants
|
2 Participants
|
1 Participants
|
|
Actual Behaviour Change in Response to a Real Air Quality Alert
Changed exercise location · No
|
15 Participants
|
18 Participants
|
5 Participants
|
10 Participants
|
SECONDARY outcome
Timeframe: Baseline and at 4 weeksPopulation: 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).
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.
Outcome measures
| Measure |
General Public/Usual Health Advice
n=34 Participants
Healthy participants with a self-reported existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
|
General Public/Alternative Health Advice
n=29 Participants
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.
|
At Risk Group/Usual Health Advice
n=7 Participants
Participants with a self-reported pre-existing health condition were randomised to receive the usual UK Air Quality Indices health advice.
|
At Risk Group/Alternative Health Advice
n=12 Participants
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.
|
|---|---|---|---|---|
|
Intentions to Adhere to Health Advice Associated With a Hypothetical High Air Pollution Scenario
|
6.69 score on a scale
Standard Error 0.23
|
6.26 score on a scale
Standard Error 0.33
|
7.58 score on a scale
Standard Error 0.28
|
6.93 score on a scale
Standard Error 0.50
|
Adverse Events
General Public/Usual Health Advice
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
General Public/Alternative Health Advice
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
At Risk Group/Usual Health Advice
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
At Risk Group/Alternative Health Advice
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
Serious adverse events
Adverse event data not reported
Other adverse events
Adverse event data not reported
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place