Assessment of Airborne Fine Particulate Matter and Particle Size Distribution in Settled Chalk Dust during Writing and Dusting Exercises in a Classroom

Airborne PM1, PM2.5, PM5 and PM10 generated during writing with three types of chalk sticks on a board and particle size distribution of chalk dust fall during writing and dusting of board were studied by portable aerosol spectrometer and particle size analyzer. 'Local Gypsum' chalk led to the highest increase in airborne particulate matter while 'Clean-Write' the least during writing. About 10% of particles in chalk dust fall during writing were finest from: 'Clean Write' (0.5 mu m) followed by 'Abroad Quality' (0.67 mu m) and 'Local Gypsum' (1.15 mu m), while 50% was finest in abroad quality (5.12 mu m) followed by 'Clean Write' (6.36 mu m) and 'Local Gypsum' (77.65 mu m). In dusting samples, 10%, 50% and 90% of particles were finest in 'Clean Write' followed by 'Abroad Quality' and 'Local Gypsum' chalks. 'Clean Write' chalk produced least total amount of PM1, PM2.4 and PM5 and PM10 per unit time in dust fall during writing. Although short-term exposure to airborne fine chalk particles may be low in classrooms, several years of exposure may be a matter of concern. Purpose of this work was to provide data that would lead to measures for minimization of health risk due to chalk dusts in classrooms.