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Effects of an air pollution personal alert system on health service usage in a high-risk general population: a quasi-experimental study using linked data
  1. R A Lyons1,
  2. S E Rodgers1,
  3. S Thomas2,
  4. R Bailey1,
  5. H Brunt3,
  6. D Thayer1,
  7. J Bidmead4,
  8. B A Evans1,
  9. P Harold5,
  10. M Hooper6,
  11. H Snooks1
  1. 1Swansea University Medical School, Swansea, UK
  2. 2Cwm Taf Public Health Team, Public Health Wales, Keir Hardie University Health Park, Merthyr Tydfil, UK
  3. 3Health Protection Team, Public Health Wales, Cardiff, UK
  4. 4Member of the Public, Swansea, UK
  5. 5Public Health England, Centre for Radiation Chemical and Environmental Hazards (Wales), Metropolitan University, Cardiff, UK
  6. 6Neath Port Talbot County Borough Council, Neath, UK
  1. Correspondence to Dr SE Rodgers, Swansea University Medical School, Swansea University, Data Science Building, Floor 3, Singleton Park, Swansea SA2 8PP, UK; s.e.rodgers{at}


Background There is no evidence to date on whether an intervention alerting people to high levels of pollution is effective in reducing health service utilisation. We evaluated alert accuracy and the effect of a targeted personal air pollution alert system, airAware, on emergency hospital admissions, emergency department attendances, general practitioner contacts and prescribed medications.

Methods Quasi-experimental study describing accuracy of alerts compared with pollution triggers; and comparing relative changes in healthcare utilisation in the intervention group to those who did not sign-up. Participants were people diagnosed with asthma, chronic obstructive pulmonary disease (COPD) or coronary heart disease, resident in an industrial area of south Wales and registered patients at 1 of 4 general practices. Longitudinal anonymised record linked data were modelled for participants and non-participants, adjusting for differences between groups.

Results During the 2-year intervention period alerts were correctly issued on 208 of 248 occasions; sensitivity was 83.9% (95% CI 78.8% to 87.9%) and specificity 99.5% (95% CI 99.3% to 99.6%). The intervention was associated with a 4-fold increase in admissions for respiratory conditions (incidence rate ratio (IRR) 3.97; 95% CI 1.59 to 9.93) and a near doubling of emergency department attendance (IRR=1.89; 95% CI 1.34 to 2.68).

Conclusions The intervention was associated with increased emergency admissions for respiratory conditions. While findings may be context specific, evidence from this evaluation questions the benefits of implementing near real-time personal pollution alert systems for high-risk individuals.


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  • Contributors RAL conceived and designed the study and contributed to drafting the manuscript and interpretation of the findings. SER contributed to study design and analyses, interpreted the findings and drafted the manuscript. ST designed the study and wrote the funder report, on which this paper is based. RB conducted the statistical analyses and contributed to drafting the manuscript. HB contributed to the study design. DT completed data extraction in preparation for statistical analysis. JB, BAE, PH and MH contributed to the interpretation of findings. HS conceived and designed the study and contributed to drafting the manuscript and interpretation of the findings. All authors were involved in manuscript revisions and have approved the final version.

  • Funding The airAware system and part of the evaluation were funded by the European Social Fund. We acknowledge additional support from The Farr Institute and the Thematic Research network for emergency and UNScheduled Trauma care (TRUST). The Farr Institute is supported by a 10-funder consortium: Arthritis Research UK, the British Heart Foundation, Cancer Research UK, the Economic and Social Research Council, the Engineering and Physical Sciences Research Council, the Medical Research Council, the National Institute of Health Research, the National Institute for Social Care and Health Research (Welsh Assembly Government), the Chief Scientist Office (Scottish Government Health Directorates), the Wellcome Trust, (MRC Grant No: MR/K006525/1). TRUST was supported by the National Institute of Social care and Health Research (Welsh Assembly Government) (2010–2015).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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