title: 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.
abstract: 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.
authors.affiliation: Swansea University Medical School, Swansea, UK.
authors.forename: R A
authors.initials: RA
authors.lastname: Lyons
authors.affiliation: Swansea University Medical School, Swansea, UK.
authors.forename: S E
authors.initials: SE
authors.lastname: Rodgers
authors.affiliation: Cwm Taf Public Health Team, Public Health Wales, Keir Hardie University Health Park, Merthyr Tydfil, UK.
authors.forename: S
authors.initials: S
authors.lastname: Thomas
authors.affiliation: Swansea University Medical School, Swansea, UK.
authors.forename: R
authors.initials: R
authors.lastname: Bailey
authors.affiliation: Health Protection Team, Public Health Wales, Cardiff, UK.
authors.forename: H
authors.initials: H
authors.lastname: Brunt
authors.affiliation: Swansea University Medical School, Swansea, UK.
authors.forename: D
authors.initials: D
authors.lastname: Thayer
authors.affiliation: Member of the Public, Swansea, UK.
authors.forename: J
authors.initials: J
authors.lastname: Bidmead
authors.affiliation: Swansea University Medical School, Swansea, UK.
authors.forename: B A
authors.initials: BA
authors.lastname: Evans
authors.affiliation: Public Health England, Centre for Radiation Chemical and Environmental Hazards (Wales), Metropolitan University, Cardiff, UK.
authors.forename: P
authors.initials: P
authors.lastname: Harold
authors.affiliation: Neath Port Talbot County Borough Council, Neath, UK.
authors.forename: M
authors.initials: M
authors.lastname: Hooper
authors.affiliation: Swansea University Medical School, Swansea, UK.
authors.forename: H
authors.initials: H
authors.lastname: Snooks
keywords: AIR POLLUTION; HEALTH SERVICES; RECORD LINKAGE