Impact of Ambient Particulate Matter on the Skin’s Immune System

Abstract

Skin is the outermost layer of the human body. The main functions of the skin include protecting the body from external harm, maintaining homeostasis, sensory perception, and thermoregulation. The skin contains many immune cells that participate both in innate and adaptive immunity. Proper skin function is disrupted when exposed to harmful environmental pollutants, such as airborne particulate matter, which aggravates the severity of skin diseases, such as eczema, psoriasis, and atopic dermatitis. Air pollution kills approximately five million individuals annually, and the death rate continues to rise. Many studies have been conducted regarding the role of particulate matter in the respiratory system. In contrast, there is minimal data available on the impact of particulate matter on the skin's immune system. However, there is more information available in recent years; for instance, PM exposure impairs skin barrier function by activating different inflammatory pathways, dysregulates T cell differentiation, activates NLRP3 inflammasome, and induces pro-inflammatory cytokine secretion. Therefore, this review assiduously discusses the impact of ambient particulate matter on the skin's immune system.