Which post-natal exposure is linked to cognitive impairment?

Lead exposure is significantly linked to cognitive impairment, particularly in children. This is due to lead's neurotoxic properties, which can adversely affect brain development and functioning. Research has shown that even low levels of lead in the blood can lead to declines in cognitive abilities, such as decreased IQ, difficulties in learning, and behavioral problems. The effects of lead exposure can persist long into adulthood, making it a critical public health concern.

The other choices, while they can have varying impacts on health, do not have as direct or profound a link to cognitive impairment as lead. Chemical pollutants and secondhand smoke can affect overall health and development, but lead specifically targets neurological functions. Noise pollution is associated with stress and sleep disruption but is less directly correlated with cognitive impairment compared to lead exposure.