Fig. 2.

a) Boxplots of some analysed pollutants (line = median, box = inter-quartile range, whiskers = ±1.5 × inter-quartile range). b) Diurnal variations of levels of measured pollutants computed over the hourly averaged data during the sampling period (e.g., 6:00 refer to averaged data between 6:00 and 7:00). Each plot reports the average level as a filled line and the associated 75th and 99th confidence intervals calculated by bootstrapping the data (n = 200). In purple particle number data from SMPS and APS, which were roughly categorised as: nucleation (14–30 nm), Aitken nuclei (30–100 nm), accumulation (0.1–1 μm) and coarse particles (1–20 μm); in red gaseous pollutants; in black non-gaseous pollutants and in green some micro-meteorological variables. Data of airport traffic only refer to civil aviation movements. (For interpretation of the references to colour in this figure caption, the reader is referred to the web version of this article.)