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[quote=Anonymous]I really hope you are an atmospheric scientist and can explain the issue better. Several studies found the same thing, and it’s that ultra fine particles are smaller and in effect are pushed down without time for them to become bigger and so are more easily inhaled. If the jets couldn’t push stuff down, what would the the use of jets or basic airplanes in crop dusting? No idea if that’s anything but that’s how it helped me to visualize what they call effect of velocities, wind and wing vortices below.

Anyway, here you go, but there’s a ton more from Europe, Australia etc, so perhaps you could come back and explain it to us, with the view as to not reassuring people but being objective.

UWA MOV-UP study:

To get a better picture of the potential extent of population exposures to aircraft- related ultrafines, and to model the potential extent of elevated ultrafine particles, we assigned emissions to aircraft landing and wind patterns observed during our study (Figure 20).
There is a relatively rapid downward transport of these aircraft-emitted UFPs and relatively little time for their physical aging due to coagulation with larger particles. This downward transport is due to a combination of large-scale daytime, convective velocities of up to one meter per second and local scale wingtip vortices that can extend vertically downward for several hundred meters at similar, superimposed velocities.47 This results in plumes from descending aircraft reaching ground level in approximately a few minutes near the airport and up to 15 to 20 minutes at 15 km downwind from the airport.
At these plume transport times, 10 to 20 nm UFPs emitted by jet engines have a characteristic coagulation half-life of about an hour, assuming that they are emitted into a background aerosol with a number concentration of 1x104 particles per cubic centimeter and count mean diameter of 0.2 μm.48 It is not surprising that the typical size of these UFPs in the downwind footprint are typically between 10 and 30 nm, indicating minimal coagulation losses.
The model results are similar to the spatial pattern of the Ultra-UF PCA feature derived from mobile monitoring measurements. The air quality model results and the map of Ultra-UF from mobile monitoring both suggest that communities underneath and downwind of landing aircraft may be exposed to this source of air pollution.
The differences in the spatial extent of aircraft versus roadway traffic UFP are important
to consider from a population impact perspective. We observed concentrations of total
UFP (10 – 1000 nm sized particles) to be higher at the near-roadway fixed site compared to concentrations observed at the near-airport fixed sites. However, most people spend a relatively small proportion of their time on a major roadway (e.g., during commuting), and because of
the relatively short distances over which roadway UFP decays downwind of major roadways, roadway UFP would affect only a narrow swath of near-roadway residences and other buildings.
In contrast, the affected areas experiencing elevated aircraft UFP tend to be larger. Therefore, considering the map shown in Figure 20, there is the potential for more people to be affected by UFP from aircraft than from roadway sources, albeit at lower concentrations. Moreover, those living within the area affected by landing aircraft emissions may be exposed to relatively higher concentrations of smaller sized ultra-UF particles.[/quote]

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