Occupation

Intense prolonged exposure to dusts and chemicals can cause
COPD independently of cigarette smoking, though smoking
seems to enhance the effects of such occupational exposure to
increase the risk of developing COPD. About 20% of diagnosed
cases of COPD are thought to be attributable to occupation; in
lifelong non-smokers this proportion increases to 30%.
Exposure to noxious gases and particles—such as grain,
isocyanates, cadmium, coal, other mineral dusts, and welding
fumes—have been implicated in the development of chronic
airflow obstruction. Thus, a full chronological occupational
history should be taken, as relevant occupational exposures are
often missed by clinicians.