Exposure to particulate matter (PM) air pollution increases the risk for myocardial infarctions, strokes, and cardiovascular mortality. A variety of responsible mechanisms have been described, including PM-induced elevations in blood pressure. Observational studies and controlled experiments have provided evidence that PM is capable of acutely increasing blood pressure in certain scenarios. Enhanced sympathetic tone and vascular dysfunction due to PM-induced systemic oxidative stress/inflammation are leading explanations. The hemodynamic responses to air pollution may be altered by underlying cardiovascular risk factors and the chemical composition of the PM. However, even the small elevations in blood pressure observed following certain exposures to PM have tremendous public health implications, due to the ubiquitous nature of air pollution.