Fig. 2

Seasonal differences of particulate air pollution level in Ulaanbaatar, Mongolia. Ambient air was sampled during the health survey. Daily mean of mass concentrations of PM2.5 (left panel of a) and PM10 (right panel of b) were presented as boxplots. Each boxplot shows the most extreme values of the daily mean PMs (maximum and minimum values), the lower and upper quartiles, and the median. The bottom, middle and top lines of each box correspond to the 25th percentile, median, and the 75th percentile, respectively. Seasonal variations of particle size distributions during the health survey (summer and winter) in Mongolia were presented (b); solid line, number concentration; dotted line, surface area; dashed line, mass concentration. Particle size is expressed in logarithmic scale