These exposures include organic and inorganic dusts and
chemical agents and fumes. An analysis of the large US
population-based NHANES III survey of almost 10,000
adults aged 30-75 years, which included lung function
tests, estimated the fraction of COPD attributable to work
was 19.2% overall, and 31.1% among never smokers16.
These estimates are consistent with a statement published
by the American Thoracic Society that concluded that
occupational exposures account for 10-20% of either
symptoms or functional impairment consistent with COPD26