Methodology for Estimating the Lifelong Exposure to PM2.5 and NO2—The Application to European Population Subgroups

Health impacts of air pollutants, especially fine particles (PM2.5) and NO2, have been documented worldwide by epidemiological studies. Most of the existing studies utilised the concentration measured at the ambient stations to represent the pollutant inhaled by individuals. However, these measurement data are in fact not able to reflect the real concentration a person is exposed to since people spend most of their time indoors and are also affected by indoor sources. The authors developed a probabilistic methodology framework to simulate the lifelong exposure to PM2.5 and NO2 simultaneously for population subgroups that are characterised by a number of indicators such as age, gender and socio-economic status. The methodology framework incorporates the methods for simulating the long-term outdoor air quality, the pollutant concentration in different micro-environments, the time-activity pattern of population subgroups and the retrospective life course trajectories. This approach was applied to the population in the EU27 countries plus Norway and Switzerland and validated with the measurement data from European multi-centre study, EXPOLIS. Results show that the annual average exposure to PM2.5 and NO2 at European level kept increasing from the 1950s to a peak between the 1980s and the 1990s and showed a decrease until 2015 due to the implementation of a series of directives. It is also revealed that the exposure to both pollutants was affected by geographical location, gender and income level. The average annual exposure over the lifetime of an 80-year-old European to PM2.5 and NO2 amounted to 23.86 (95% CI: 2.95-81.86) and 13.49 (95% CI: 1.36-43.84) mu g/m(3). The application of this methodology provides valuable insights and novel tools for exposure modelling and environmental studies.