Chemical spray to banish fog
An aircraft has been flying around the Cheltenham area spraying fog banks with water droplets. While the reason for this is not initially apparent to an observer on the ground, Dr George Elton at Battersea Polytechnic does have one. He is testing a technique for condensing water droplets and, while the first reports from the pilot are optimistic, Dr Elton has not yet had the opportunity to analyse the results for himself. This means it is much too early to think that an end to our fog problems is in sight.
The new method depends on the fact that the surface of a fog droplet is negatively charged, so introducing positively charged droplets should promote the agglomeration by attraction of droplets and hence cause them to fall. A number of chemical compounds will, in small concentrations, produce this effect as Dr Elton has shown in the laboratory. He has already presented his preliminary laboratory findings to the Congress of Surface Activity in London earlier this year. Now comes his practical test.
Advertisement
In the current Cheltenham trial the material being used to create positively charged droplets is dilute benzalkonium chloride, which is also a detergent. One gallon of the solution is estimated to be sufficient for one acre, but this is dependent on the density of the fog being sprayed and the local turbulence and wind conditions, which affect the rate of collision between droplets.
Unfortunately droplets of pollution smog contained within most banks of fog possess a higher surface negative charge than clean fog. Since the object of spraying these banks is to override this total negative charge, it is almost certain that higher concentrations of the spray chemical would be needed. This obviously has implications for the environment. Spraying chemicals merely to disperse other chemicals is not an intuitive solution.
From The New 杏吧原创, 19 December 1957