Evaluation of indoor/outdoor urban air pollution by magnetic, chemical and microscopic studies

The difference in magnetic mineralogy, especially the lack of metallic iron in PM, can be explained by the limitation of dust samplers that cannot collect grains larger than roughly 50 μm due to our microscopic observations. PM samplers collect population of dust with smaller grain size than vacuum cleaner or simple sweeping of a floor. The difference in granulometry and outdoor/indoor sources could be one of the reasons for which we did not observed the simple relation between magnetic susceptibility of ID and PM.