VOCs, such as formaldehyde and benzene, are known to impair immune cell function, including suppressing lymphocyte proliferation and antibody production [113], while exposure to PAHs can also cause thymus atrophy, as persistent activation of the aryl hydrocarbon receptor (AhR) can impact thymocyte proliferation, ultimately reducing T lymphocyte populations in the thymus [114]. Here, AHR is linked to thymus atrophy.