Exposure to ambient particulate matters may increase blood pressure (BP) within hours to days. The underlying biologic pathways include autonomic nervous system imbalance and arterial vascular dysfunction or vasoconstriction because of systemic oxidative stress and inflammation. Likewise, tobacco smoke exposure of pregnant mothers increases systolic BP of their offspring in early infancy. Parental smoking also independently affects systolic BP among healthy preschool children. Noise exposure, notably in night, is associated with catecholamine secretion, increased BP and a pre-HTN state even in pre-school age children.