Exposure assessment in epidemiological studies is a tricky issue, because of the difficulty of constantly tracking people’s activity and location, both of which can affect the exposure to pollution. Researchers at CREAL have shown how using smartphone technology can help to reduce this bias in health effects estimates.
Audrey de Nazelle, a postdoc at Mark Nieuwenhuijsen’s lab who has currently started her own group at the Centre for Environmental Policy, Imperial College in London, used the CalFit smartphone technology to track person-level time, geographic location, and physical activity patterns for improved air pollution exposure assessment. CalFit is a ubiquitous sensing technology developed at UC Berkeley. It consists on using a GPS and an accelerometer in a smartphone to record the location and physical activity of the carrier through energy expenditure and activity tracking algorithms. de Nazelle and her colleagues at CREAL distributed CalFit-equipped smartphones to 36 subjects in Barcelona to obtain information on physical activity and geographic location. This information was then linked to space-time air pollution mapping.
The authors of the paper, published in Environmental Pollution, found that information from CalFit could substantially alter exposure estimates. For instance, travel activities – which wouldn’t have been measurable without the use of the mobiles – accounted on average for 6% of people’s time and 24% of their daily inhaled NO(2).
The potential of this technology for epidemiological studies is enormous. As the authors state, the large number of mobile phone users makes this technology a potential unobtrusive means of enhancing epidemiologic exposure data at low cost. In fact, they are now using it in several epidemiological projects they are involved in, such as the ERC-funded BREATHE study, the EC-funded PHENOTYPE, and the HELIX and EXPOsOMICs studies.
You can read a related interview to de Nazelle here.
de Nazelle A, Seto E, Donaire-Gonzalez D, Mendez M, Matamala J, Nieuwenhuijsen MJ, Jerrett M. Improvingestimates of airpollutionexposurethroughubiquitoussensingtechnologies.EnvironPollut. 2013 Feb 13;176C:92-99