Countercurrent Packed Towers are the most common of the aeration methods know as air stripping. It is often used in reference to packed tower aeration. These towers are very effective in removing volatile organic chemicals.

The counter-current scrubbers are preferably used for air streams with few and similar contaminants. It uses a chemical treatment to eliminate contaminants. It is a low cost and compact device offering an optimal contact between gases and washing liquid. Thus a heat transfer is obtained which permits heating or cooling of the treated air as required. It is the most economical solution, using the least space, for many air pollution problems