Fig. 1. Changes in facial skin characteristics according to high-particulate matter (PM) period and low-PM period. (A) Transepidermal water loss (TEWL), (B) erythema index, (C) melanin index, (D) pore, (E) wrinkle, (F) sebum, and (G) skin tone. Facial skin characteristics were plotted for two periods and compared between the two periods using paired t-test or Wilcoxon signed-rank test. Box indicates lower and upper quartiles. Central line indicates median value; Black points at the ends of the whisker indicate upper and lower extreme values. Values are presented as mean±standard deviation.
