Joint effect of heat and air pollution on mortality in 620 cities of 36 countries

Combined heat and air pollution causes higher mortality. That is the finding of a recent study using data from 620 cities in 36 countries worldwide, including 262 cities in 18 countries in Europe. Higher levels of daily PM, NO2 and O3 cause higher heat-related mortality effects, and higher levels of mean air temperature during warm months cause increased PM- and O3-related mortality. Public health interventions and adaptation actions in response to climate change should therefore consider the synergistic health effects of heat and air pollution and mitigate both exposures.