Schematic view of respiratory system homeostasis in response to dust and chemical exposure.

Occupational exposure to dust and chemical leads to irritation and initiation of inflammatory responses in the host respiratory system, that require the engagement of different regulatory cellular pathways. Alveolar macrophages demonstrate the pro-inflammatory and anti-inflammatory properties that contribute to the pulmonary hemostasis. IAM: intra alveolar macrophage, PI: type one pneumocyte, PII: type two pneumocyte, BC: basal cell, PCCoC: pseudostratified ciliated columnal epithelial cell, SCCoC: simple ciliated columnar epithelial cell, SCCuC: simple ciliated cuboidal epithelial cell, GC: goblet cell, CC: Clara cell, SM: smooth muscle.