Air pollution is a major public health concern, given its significant impact on the population’s health and the fact that it affects everyone. Among the health effects of air pollution, a distinction is made between those resulting from short-term exposure and those associated with long-term exposure. Short-term effects are acute clinical, functional, or biological "manifestations" that occur within a short period (a few days or weeks) after exposure to air pollution. Several epidemiological studies document the short-term health impacts of this pollution and consistently find significant associations between high ozone concentrations—typically observed during the summer—and increased mortality and hospitalizations for respiratory causes. Particles with a diameter of less than 10 µm (PM10) are also associated with an increase in all-cause mortality and an increase in hospitalizations for respiratory and cardiovascular causes. All these studies show that, a priori, there is no protective threshold below which no health impact is observed. [...] (R.A.)