Objective: This study explores the clinical correlation between the air pollutant PM2.5 and the induction of psoriasis flare-ups through the disruption of the immune barrier. Methods: Air quality data, the average mass concentration of the primary atmospheric pollutant PM2.5, and meteorological data spanning from November 2023 to March 2024 were gathered from 9 air quality monitoring stations situated within our city, courtesy of the local Meteorological Information Center. Psoriasis cases were sourced from our hospital's dermatology department, encompassing patients diagnosed and treated from November 2023 to March 2024 and residing within the city. Results: From January 2023 to May 2024, aberrant expression of Th1 cells and Th2 cells was observed in psoriasis flare-up patients. Spearman correlation coefficient analysis revealed a positive correlation between PM2.5, PM10, and Th1 cells, and a negative correlation with Th2 cells, exhibiting significant differences (P < .05). Supplemental Figure 1 illustrates an increase in psoriasis flare-ups on the fifth day following a unit increase in PM2.5 concentration, with an excess risk (ER) value of 0.046 [95% confidence interval (CI): 0.137-0.893]. Conversely, after an increase of 1 unit of PM10, there was a decrease on the third and fourth days, followed by increases on the fifth, sixth, and seventh days, with ER values of 0.038 (95% CI: 0.013-0.067), 0.045 (95% CI: 0.019-0.073), 0.051 (95% CI: 0.034-0.078), 0.057 (95% CI: 0.045-0.083), and 0.061 (95% CI: 0.051-0.087), respectively. Conclusion: Air pollutant PM2.5 could potentially exacerbate psoriasis flare-ups by compromising the immune barrier, suggesting a plausible mechanism linked to the onset of this condition.