Pneumoconiosis is one of a group of interstitial lung disease caused by breathing in certain kinds of dust particles that damage your lungs.
Because you are likely to encounter these dusts only in the workplace, pneumoconiosis is called an occupational lung disease.
Pneumoconiosis usually take years to develop. Because your lungs can't get rid of all these dust particles, they cause inflammation in your lungs that can eventually lead to scar tissue.