Figure 1

Comparison of the bacterial diversity indexes in air samples from the suburban (> 1.1 µm, red), suburban (< 1.1 µm, green), urban (> 1.1 µm, blue), and urban (< 1.1 µm, purple) groups. Box plots represent (from top to bottom) maximum, upper-quartile, median, lower-quartile, and minimum values. The median in three points (August, September, October) is shown for each of the four sample groups.