Traffic-related PM2.5 induces cytosolic [Ca²⁺] increase regulated by Orai1, alters the CaN-NFAT signaling pathway, and affects IL-2 and TNF-α cytoplasmic levels in Jurkat T-cells.

The atmospheric particulate matter with a diameter less than or equal to 2.5 um (PM2.5) can result in increased immune system damage or diseases, however, the possible mechanism remains unclear.