Figure 323
Fig. 323
normal (341x430, 10 KB) large (813x1024, 29 KB) EPS (11 KB)
(a) Emission indices of detectable volatile particles in number per kg fuel measured in situ in plumes of various subsonic aircraft and the supersonic Concorde. The aircraft were examined as part of several missions in Europe and the USA; aircraft types are indicated in the legend. Ultrafine volatile particles with radii greater than 2 to 3 nm were measured at plumes ages less than 20 s (ATTAS, B737, DC-8, B757, T-38, F-16), with radii greater than 4 to 5 nm at ages of 0.25 to 1 h (Concorde), and with radii greater than 6 nm at ages of 1 to 2 min (B747, DC-10, A340). Observations involving the same aircraft are connected by lines. Fuel sulfur content values were determined by chemical analysis of the fuel or inferred from in situ SO2 measurements (for B747 and DC-10). During the observations a contrail either did (filled symbols) or did not (open symbols) form. (b) Same as (a), but for the emission indices of soot particles. Values from Howard et al. (1996) for a modern jet engine (about 1013/kg) are below the range of values shown.