Ventilation was non-existent in the smaller concerns?

1) Does "Ventilation was non-existent in the smaller concerns" mean "Ventilation was non-existent because paying even more little attention to it (the ventilation)"?
2) "Some of the women had the cartilage separating their nostrils eaten away by constant inhalation of chemicals"?
What had been eaten away? The cartilage? Or their nostrils?

Context:

This was not an isolated example. In the twenty-eight factories 'run by the people' in the Gulou district, the old centre of town where drums used to mark the night watches, rubbish was found everywhere. Ventilation was non-existent in the smaller concerns. Many of the workers were women who had joined during the Great Leap Forward. Most had no work experience and were given very little protective equipment, some only donning straw hats. Exposure to chemical components and silicon dust commonly caused red eyes, headaches, itches and rashes. Some of the women had the cartilage separating their nostrils eaten away by constant inhalation of chemicals. Heatstroke, with temperatures near the furnaces ranging from 38 to 46 degrees Celsius even in the middle of the winter.