posted 01-04-2001 01:01 PM            

First, some facts.
The KC-10 aircraft can off-load 250,000 pounds of fuel. (Source: AF News)

Second, anything released into the atmosphere will disperse. It does not stay concentrated where it was released. Concentrations downwind from a source of release can be calculated based on well-developed equations. (Source: Any atmospheric chemistry textbook, industrial hygiene text, or spill response guidance books. I used a calculator at http://www.industrialhygiene.com/calc/model.html for this purpose.)

OK, now let's make some assumptions to simplify the calculations.

1) Let's assume a KC-10 is carrying 250,000 pounds of some chemical instead of fuel. Let's further assume that somehow this KC-10 is going to spray this chemical. In order to provide a source rate for our calculations, we'll also assume that the entire load is sprayed in 30 minutes. (I know this isn't consistent with the chemtrail sightings reports which claim these aircraft fly around for hours spraying, but it gives a worst case kind of value.) This gives a source rate of 63 billion micrograms/second.

2) Now, let's further assume that our KC-10 has the amazing capability to hover. Therefore, all of the material is sprayed in one spot.

3) Let's further assume extreme stability of the atmosphere to limit the dispersion and provide maximum concentrations. We'll also assume a very low windspeed of 0.1 meter/second. (Again, this limits the amount of dispersion.)

OK, now some results. If this KC-10 was hovering and spraying right over your head (approximately 2 m high), the maximum concentration you would see on the ground would be 19.3 billion micrograms/cubic meter at 60 meters downwind.

If we take the KC-10 up to 10 meters, the maximum concentration on the ground is 80 million micrograms/cubic meter at 400 meters downwind.

Spraying at 100 meters, gives a maximum concentration of 1.7 million micrograms/cubic meter at 15,000 meters downwind.

Spraying at 1000 meters gives a maximum concentration of 37.6 micrograms/cubic meter at 80 million meters downwind.

Spraying at 2000 meters gives a maximum concentration of 0.76 micrograms/cubic meter at 3.5 billion meters downwind.

(For those who may not understand why the maximum concentration is shown at a distance downwind, think of watching the smoke for a smokestack. The smoke does not reach the ground (if at all) until some distance from the smokestack, depending upon weather conditions.)

To put these concentrations into perspective, the lowest allowable exposure level for workers I could find was for strontium chromate at 0.5 micrograms/cubic meter. This is the level workers are allowed to be exposed to 40 hours per week over a working life without significant risk of adverse affects. Another allowable exposure level for workers which may have more meaning to people is the allowable exposure level for strychnine is 150 micrograms/cubic meter. So, even at 2000 meters assuming everything above brings you down to a very low exposure level.

Now, let's add reality in.

1) The most stable atmosphere occurs on cloudy nights. "Chemtrails" are reported as occurring during bright, sunny days. This significantly reduces the stability factor which would reduce the calculated concentrations.

2) KC-10s and the aircraft supposedly sighted laying down "chemtrails" can't hover. Their movement across the sky creates an additional significant dispersion in and of itself. This again would significantly reduce the calculated concentrations.

3) The concentration downwind assumes that the source rate continues to feed the plume in order for it to reach the distance downwind for the maximum. However, any plane has a limited capacity of what it can carry and there's no way to support this kind of source rate. So, any reduction in source rate would result in reduced concentation on the ground.

4) These "chemtrails" are supposedly from spraying at much higher altitudes than 2000 m. (Sorry, I got tired of playing with the numbers and didn't go any further.) And every doubling of the height does not simply cut the concentration in half. It's a much greater reduction. (I didn't figure it out, but it's probably closer to dividing by the increase cubed, since it's dispersing in 3 directions.)

posted 01-12-2001 11:57 AM            

Thanks for the effort here Bee, it is appreciated. Will definately be studying this in conjunction with the other calculations in the Chemical Rain thread.

Random, or anybody, is there an easy way to convert expressions of this form "concentration of 0.76 micrograms/cubic meter" to parts per billion?

Bee, also it would helpful if you could supply the exact values you used in filling out the Industrial Hygiene Calculator for at least one of your examples, I haven't spent much time on it yet, but was having trouble getting any concentration result values.