An ultrasonic fog generator including a container including therein an ultrasonic nebulizer and a liquid, the ultrasonic nebulizer operative to vibrate at very high frequencies and thereby break down the liquid into a fog including tiny vapor particles, the container having an exit opening for the fog to pass therethrough, and a driver and a driving fluid, the driver being operative to cause the driving fluid to flow past the exit opening and draw out the fog through the exit opening without the driving fluid substantially entering the container.