Detailed answer

Air pollution, particularly fine particulate matter (PM2.5), can exacerbate hyperpigmentation through multiple mechanisms. Firstly, pollutants like PM2.5 can penetrate the skin barrier and trigger an inflammatory response, leading to the release of pro-inflammatory mediators that can stimulate melanocytes and cause increased melanin production. This can result in the darkening of existing hyperpigmentation or the formation of new spots.

Furthermore, air pollutants contain free radicals that induce oxidative stress in the skin. Oxidative stress can disrupt the regulation of melanin production and trigger an overproduction of melanin, contributing to hyperpigmentation.

Moreover, some pollutants, such as polycyclic aromatic hydrocarbons (PAHs), can directly bind to receptors on melanocytes, leading to the upregulation of melanin synthesis.

To mitigate the effects of air pollution on hyperpigmentation, it is important to protect the skin by cleansing it thoroughly to remove pollutants, wearing sunscreen with high SPF, and using antioxidants to combat oxidative stress. Additionally, minimizing exposure to polluted air by staying indoors and using air purifiers can also be helpful.