The Southern Oxidants Study (SOS) is a strategic alliance of research scientists, engineers, and air quality managers from universities, federal and state governments, industry, and public interest groups.

In SOS, these groups work to design and execute scientific research and assessment programs that will increase understanding of the accumulation of ozone, other oxidants, and fine particulate matter in the atmosphere near the ground.

SOS was formed in June 1988 when a group of 60 concerned scientists, federal and state agency officials, and key industry representatives gathered at the Georgia Institute of Technology in Atlanta, GA. The group considered the question of why ozone abatement measures had been largely unsuccessful, particularly in the South.

As a result, the following actions took place:

SOS received funding from a variety of sources and agencies and began the multi-year study in 1990.

The SOS research program has included:

In June 1998, SOS began making the transition from a research and assessment program concerned primarily with ozone and other oxidants in rural and urban areas within the 10 states of the southern United States, to a research and assessment program concerned with ozone, other oxidants, and fine particulate matter in this same 10-state area. An intensive study in Atlanta in 1999 focused on particulate matter composition and formation. Intensive studies in Houston/Galveston in 2000 and 2005/2006 focus on ozone accumulation and on particulate matter in regional haze.