Reply to Plane noise

Forum Index » Real Estate

Reply to "Plane noise "

Subject:

Emoticons





More smilies

Text Color: Font: Close Marks

[quote=Anonymous]That’s where the science would say you are *dead* wrong. This is all carefully worded but shows why under a flight path is way worse — in layman terms these are pushed down into you and you stand no chance

Their analysis showed that roadway air pollution particles consist of relatively larger particle sizes and higher black carbon concentrations. These particles tend to disperse over relatively short distances downwind of major roadways such as Interstate 5 and SR 99, affecting a narrow swath of near-roadway residences and buildings.

In contrast, emissions associated with aircraft consist of the relatively smaller ultra-ultrafine particle sizes and lower black carbon concentrations. Areas exposed to higher levels of aircraft-related particles tend to be larger, meaning more people are potentially affected.

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.

[/quote]

Options

	Disable HTML in this message
	Disable BB Code in this message
	Disable smilies in this message

Review message

Search Recent Topics Hottest Topics