Background: Global environmental change is exacerbating human vulnerability to adverse atmospheric conditions including air pollution, aeroallergens such as pollen, and extreme weather events. Public information and advisories are a central component of responses to mitigate the human impacts of environmental hazards. Digital technologies are emerging as a means of providing personalised, timely and accessible warnings.

Method: We describe AirRater, an integrated online platform that combines symptom surveillance, environmental monitoring, and notifications of changing environmental conditions via a free smartphone app. It was developed and launched in Tasmania, Australia (population 510,000), with the aim of reducing health impacts and improving quality of life in people with conditions such as asthma and allergic rhinitis. We present environmental data, user uptake and results from three online evaluation surveys conducted during the first 22 months of operation, from October 2015 through August 2017.

Results: There were 3,443 downloads of the app from all parts of Tasmania. Of the 1,959 individuals who registered, 79% reported having either asthma or allergic rhinitis. Downloads increased during adverse environmental conditions and following publicity. Symptom reports per active user were highest during spring (72%), lowest in autumn (37%) and spiked during periods of reduced air quality. In response to online surveys, most users reported that the app was useful and had improved their understanding of how environmental conditions affect their health, and in some cases had prompted action such as the timely use of medication.

Conclusion: Active engagement and consistent positive feedback from users demonstrates the potential for considerable individual clinical and wider public health benefits from integrated and personalised monitoring systems such as AirRater. The perceived health benefits require objective verification, and such systems need to address several challenges in providing timely, reliable and valid environmental data.