Our body processes work in a cordinated manner inorder to maintain a stable state/environment.
Homeostasis plays it's important significant role as well as other positive and negative feedback mechanism that come to play when there is a deviation in the normal body processes or when the body finds itself in a unfamiliar environment/circumstance.
When one is exposed to environmental hazards such as coal dust, asbestos and silica dust,the body notices the presence of the harmful substance in the environment and it quickly sends sensory impulse to the respiratory centre in the medulla oblongata and the pons in the brain stem and they process the signal and then send motor impulse to the respiratory organs to be taking shallow breaths so that it won't inhale the harmful substances/chemicals and this will cause the total lung volume to start decreasing as the body gets used to taking in limited amount of air and this will eventually cause the lungs to shrink reducing it's structure and functions.