Lead Paint Damaged lead paint in house occupied with small children can lead to lead poisoning
Professional equipment Equipment that is well maintained is needed in order to provide professional indoor air quality evaluations such as the hygrometer identified in this photo
Heating and air systems and air quality Dirty heating and air coils, such as this can lead to mold growth in the ductwork and in the property resulting in poor air quality
Asbestos Most think of asbestos only on pipes but it is also found in window glazing, drywall mudding, ceiling tiles, floor tile and sheet vinyl and many other building materials
Mold and moisture Mold such as this is not common in buildings without water loss such as pipe leak, flooding or inadequate climate control to maintain relative humidity below 60%
Crawlspaces Conditions such as this are due to either long term water infiltration or pipe leak and require professional mitigation