Ozone is a highly reactive gas that is a pervasive air pollutant at ground level. It is a major component of urban smog, forming when emissions from mobile and industrial sources interact with sunlight. The study of the effects of long-term ozone exposure on lung complex carbohydrates, described in this report, was one of eight laboratory studies supported by the NTP/HEI collaborative agreement. In addition to studying lung and nasal structure and function, investigators studied other constituents of lung connective tissue. Dr. Bhandaru Radhakrishnamurthy at the Tulane University School of Public Health used standard biochemical methods to measure changes in the content, structure, and function of complex carbohydrates in lung tissue from male and female rats exposed to 0, 0.12, 0.5, and 1.0 ppm ozone for 20 months.