In the fourth paragraph, add in after "...the greatest presumed contaminant source strength", "Determine the number of ventilation systems serving the building. Then, determine if the individual floor plates served by each single ventilation system are larger or smaller than 25,000 square feet. If they are smaller, take at least one sample for every 25,000 square feet, or fraction thereof, served by a single ventilation system. If they are larger, take one sample per floor plate. For example, a 110,000 square foot building with ten 11,000 square foot floors, served by a single ventilation system, needs only five samples - one per 25,000 square feet (or fraction thereof) because each 11,000 foot floor plate is smaller than 25,000 square feet. However, a building with ten 30,000 square foot floors, also served by a single ventilation system, needs ten samples for the building because each 30,000 floor plate is larger than the 25,000 sq ft criterion." Delete, "For example" in the following sentence.