COPD - Background in the US. Chronic obstructive pulmonary disease (COPD) includes chronic bronchitis, emphysema, bronchiectasis, and chronic airway obstruction. Estimated prevalence of 8.5% in the U.S. In 1999 COPD was the fourth leading cause of death in US (> 124,000 deaths) .
Among construction workers performing tunneling operations:
Median values for respirable dust and silica (mg/m3 )
151 personal measurements were analyzed from 80 workers on 36 construction sites