Indoor air quality in university classrooms and relative environment in terms of mass concentrations of particulate matter.

The mass concentrations of coarse (PM10) and fine (PM2.5) particulate matter were measured in different classrooms and relevant indoors areas of Democritus University, School of Engineering, Xanthi, with portable aerosol monitoring equipment. Two sampling campaigns were conducted in different seasons. The results indicated that the average concentrations in classrooms ranged from 32-188 microg/m3 and 25-151 microg/m3 for PM10 and PM2.5, respectively. Concentration levels above 300 microg/m3 were usually recorded, while the PM2.5/PM10 ratio was about 0.8. As expected, PM10 and PM2.5 average concentrations were significantly higher in the open-access meeting place of common use, indicating the significance of student trespassing and occasional smoking in the deterioration of indoors air quality.