Which of the following is a main source of lead exposure in residential properties?

Lead-based paint is a significant source of lead exposure in residential properties, particularly in homes built before 1978 when its use was banned in many countries, including the United States. The risk arises when the paint deteriorates due to chipping, peeling, or wear, leading to lead dust or paint chips that can be ingested or inhaled, particularly by young children. As they are more vulnerable to the effects of lead exposure, this hazard poses a serious public health concern.

On the other hand, while solar panels, natural gas lines, and asphalt shingles have their own safety considerations, they are not primary sources of lead exposure. Solar panels are generally made from materials that do not contain lead. Natural gas lines are focused on transporting gas and do not pose a lead exposure risk. Asphalt shingles, while they can contain various materials, typically are not associated with lead exposure in residential settings. Thus, lead-based paint remains the clear and prominent hazard in this context.