Sulfur dioxide is a gas that is created when sulfur is burned. It is a harmful substance that can be released into the air and can cause breathing problems and pollute the environment. Full definition
However, while field measurements of sulfur dioxide emissions are increasing, they still remain too sparse to piece together a cohesive global picture. (sciencedaily.com)
More importantly, I've heard people arguing that the decreased warming is the result of increased sulfur dioxide emissions from Chinese coal. (reason.com)
And the same approach that brought a decline in sulfur dioxide emissions can have an equally dramatic and permanent effect on carbon emissions. (dotearth.blogs.nytimes.com)