Figure 1

The correlation between calcium (PC1, soil related constituents) concentration in the PM _10–2.5 and PM _2.5–0.2 samples and inflammatory (A; TNF-α) and cytotoxicity (B; MTT) responses in mouse macrophages after exposure to three different doses (50, 150 and 300 μg/ml for 24 h) of indoor or outdoor air PM samples. The Pearson correlation coefficients are included in the figure panel. Seasons are differentiated by colors (blue = winter, green = spring, yellow = summer, red = autumn). X-axis and Y-axis (A) are both in logarithmic scales whereas Y-axis (B) in linear scale.