Exposure to coffee dust has been associated with respiratory symptoms, including asthma and changes in lung function. The Institute of Health and Welfare identify coffee dust as a causal agent of occupational Asthma.   

Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure.