Assessing the Levels of Regulated Metals in an Urban Area: A Modelling and Experimental Approach

The toxic elements released into the atmosphere are a worldwide issue due to their negative effects on human health and ecosystems. In this study, data from extensive toxic elements experimental monitoring campaign was used to evaluate the performance of the WRF-CAMx modelling system to simulate the concentrations of As, Ni, Cd and Pb over European urban areas, using the Lisbon urban area as a case study. The simulated toxic element concentrations highlighted the need to perform more measurements, mainly near man-made sources, in space and time for Cd, Ni and Pb since these elements are affected by atmospheric emission from non-continuous anthropogenic sources. Measured As levels were very low and were not considered for the model evaluation. The air quality modelling system tends to overestimate the Ni, Cd and Pb levels. The model results for Pb are in the same order of magnitude as the measurements; however, for Ni and Cd high biases were obtained. Despite the uncertainty of the meteorological model, which could affect the air quality modelling performance, the simulation limitations are mainly attributed to an inaccurate temporal profile, source allocation and magnitude values of the domestic, industrial, road and maritime transport emission sectors.