Ozone found inside human bodies could be a crucial aggravator of the hardening of arteries, which can result in heart attack and has been linked to diseases such as lupus, multiple sclerosis and rheumatoid arthritis, says a study out this week. Scientists at the Scripps Research Institute, California, discovered last year that human antibodies produce ozone. As a reactive molecule, further investigation has gone into what effects the gas is actually having when produced in the body.