Fig. 1

Particle concentrations measured inside a jetfighter shelter at a non-commercial airfield (a and b) and at a non-commercial airport (c) (see also Additional file S1 A). a: Total particle number concentrations (a) and particle number size distribution time series (b) inside the shelter measured during jetfighter leaving the shelter (PL), arriving at the shelter (PA), and fuel truck (FT) fueling the plane. The vertical solid and dashed black lines show when the jet engine is started or fuel truck arrives to the shelter and when the engine is switched off or fuel truck leaves the shelter. Horizontal thick black line shows the averaging period to calculate exposure and dose levels presented in Table 2. Particle sampling time for one flight cycle (tPM4) for mass fraction smaller than 4 μm (mPM4) gravimetric analysis is shown with gray vertical bar. b: Average particle number (a) and mass (b) size distributions. c: Total particle number concentrations measured at a commercial airport (CAP). The inserted sub-figure shows the average particle size distribution measured by the NanoScan during the measurement period