Fig. 1
Parameterised response (lines) for a first-order instrument according to Doebelin (1990) with τ=0.2 seconds and τ=1.2 seconds (lines) and averaged experimental data during a 90% step change in concentration with UHSAS (squares) and PCASP-X2 (circles).
Table 1. OPC channel classification, with geometric mean (D m) and upper cut off diameter (D u)
Fig. 2
Relative flux uncertainty due to limited counting statistics (black) and flux uncertainty due to random instrument noise (grey). Median values are denoted by squares with IQR error bars.
Fig. 3
Averaged atmospheric stability classified according to Foken (2008) as ζ=(z−d)/L. Very unstable: ζ<−1.83 <, unstable: −0.55>ζ>−1.83, weak unstable: −0.55>ζ>−1.183, neutral: −0.183>ζ<−0.011, weak stable: 0.011<ζ<0.22, stable: 0.22<ζ<0.917, very stable: ζ>0.917.
Fig. 4
Averaged daily patterns of latent heat fluxes (a), sensible heat fluxes (b), friction velocity (c) and CO2 fluxes (d) for the different seasons: spring (dots), summer (circles), fall (crosses) and winter (squares).
Fig. 5
Daily averages of particle number concentrations (N) and fluxes (F N) throughout the 1-yr measurement period.
Fig. 6
Averaged particle number size distributions (PNSD) expressed as ensemble log normal distributions for the different seasons: spring (light grey, thick line), summer (medium grey), fall (dark grey), and winter (black). Urban size distributions (solid lines) vs. suburban ones (dashed lines).
Table 2. Median and IQR (in brackets) of total particle number fluxes (F N), concentrations (N) and stability parameter (ζ) for the different seasons and for two different land use sectors. Inter-source region significance with *(p<0.05, Kruskal–Wallis ANOVA) and inter-season significance (ABCD).
Fig. 7
Averaged diurnal courses of normalised size-resolved number concentrations (N) for summer (top panel) and winter (lower panel). Y-Axes in log scale and non-continuous.
Fig. 8
Size-resolved particle exchange velocities (a) and fluxes (b) with median (symbols) and 25th/75th percentiles (error bars) differentiated in two source regions: urban (black) and suburban (grey).
Fig. 9
Averaged daily patterns of total number (green) and total mass flux (blue) during the four seasons. Filled areas (inter quartile range) symbolise the day-to-day variation. Single 30-minute averages and respective variances are calculated from 33 (min) to 51 (max) data points, according to results from the quality control scheme (Section 2.1).
Fig. 10
Averaged diurnal courses of size-resolved number fluxes (F N) for summer (top panel) and winter (lower panel). Y-Axes in log scale and non-continuous.
Fig. 11
Median correlation of exchange velocity and bin-aggregated flux drivers friction velocity u* (a), wind speed U (b), stability parameter ζ (c) and CO2 flux (d) with the respective coefficients for a linear regression: y=p1 x+p2, and a second-order polynom: y=p1 x2+p2 x+p3. Grey scale denotes particle diameter from light grey (0.06 µm) to black (1 µm). Ultrafine particles (triangles), accumulation mode particles (circles), and super micrometre particles (squares).