In children, blood lead levels (BLLs) more than ____ are associated with decreased intellectual performance and other adverse health events.

The association between blood lead levels (BLLs) and adverse health effects in children is well established in public health research. A BLL greater than 10 micrograms per deciliter (ug/dL) has been identified as a threshold for concern, correlating with decreased intellectual performance and various other health issues.

This threshold is significant because it reflects the level at which lead exposure has been shown to cause neurodevelopmental harm in children, including cognitive deficits, attention problems, and behavioral issues. Public health guidelines, such as those from the Centers for Disease Control and Prevention (CDC), have emphasized the risks associated with elevated lead levels and have set preventative measures to reduce exposure in environments where children live and play.

Understanding the impact of lead on children's health is critical for environmental health specialists in their efforts to prevent lead poisoning, especially in areas known for potential lead exposure sources such as old paint, plumbing, or contaminated soil.

The other options do not align with established public health guidelines. For instance, lower thresholds like 2 ppm or 5 AO are not recognized as significant concerning adverse health effects in children, and 15 ppm is excessively high based on current medical understanding of lead toxicity.