Exposure to particulate matter pollution has been linked to an increased risk of mortality and hospitalizations due to respiratory and cardiovascular causes. Its effects have been observed in short-term studies, which have linked daily variations to health outcomes, as well as in long-term studies, which have followed cohorts of individuals over extended periods of time. Recent studies have suggested that particulate pollution may also affect fetal growth and the duration of pregnancy. Effects are observed at low concentrations of particulate matter, and it is unclear whether there is a threshold effect. This systematic review assesses the existing level of epidemiological evidence regarding the association between particulate matter pollution and human health. Further investigation is needed to clarify and quantify potential effects and to generate research hypotheses to be tested, as well as plausible biological mechanisms.