The Effect of Moisture on the Growth of Cigarette Smoke Particles

The effect of water vapour on the growth of cigarette smoke particles was investigated by a light-scattering method which can measure the particle size distribution and the refractive index. The particle growth, below 90 % relative humidity, was less than 10 % for both main and side-stream smoke. The results were discussed with equations derived from the weight changes of smoke condensate in moist air, and with the changes of the refractive index. Calculations showed that the cigarette smoke particle reaches equilibrium very quickly and that it doubles its radius at about 99.5 % relative humidity.