EVA: A high-resolution model system for assessment of health impacts from air pollution and related external costs.

The integrated model system EVA (Frohn 2006, 2007, Andersen 2006, 2007, 2008, Brandt 2010, 2013), is based on the impact-pathway chain and is used for assessment of health impacts from air pollution, including both health effects and related external costs (sometimes also referred to as “indirect costs”) which can be attributed to air pollution exposure. Chemical components important for health impacts and included in the EVA system are: nitrogen dioxide (NO₂), sulphur dioxide (SO₂), ozone (O₃) and particulate matter (PM_2.5), where the individual constituents of PM_2.5 are: mineral dust, black carbon (BC), organic matter (OM), secondary inorganic aerosols (SIA – i.e. nitrate, sulphate and ammonia), secondary organic aerosols (SOA) and sea salt.

The EVA model is coupled to the air pollution models DEHM (Danish Eulerian Hemispheric Model) and UBM  (Urban Background Model) for regional-scale and local-scale health impact assessments, respectively. EVA includes gridded population data, exposure-response functions for health impacts in terms of morbidity and mortality, and economic valuation of the health impacts from air pollution.

The EVA system includes the best available and most accurate, yet computationally demanding methods, used in each part of the impact-pathway chain. The EVA system uses comprehensive and thoroughly tested chemistry-transport models when calculating air pollution levels in general as well as scenarios describing how specific changes in emissions of pollutants to the air affect air pollution levels at regional and local scale.

To calculate the impacts of the total air pollution levels or of emissions from a specific source or sector,  concentrations and address-level population data are combined to estimate human exposure, and then the response is calculated using an exposure-response function (ERF) of the following form: R = A · C · P, where R is the response (e.g. in cases, days, or episodes), C the  concentration (i.e. the total concentration or additional concentration resulting from emissions of a particular emission source), P the affected share of the population, and A is an empirically determined constant for the particular health outcome, typically obtained from published cohort studies. The updated exposure-response functions (ERFs) used in the EVA system is documented in Andersen  et al., 2019 (in Danish).