Researchers assessed satellite data on vegetation density and compared it with levels of PM2.5 pollution (fine dust and solid particles in the air) and ozone, as well as with incidence and mortality rates. PM2.5 and ozone directly increase the risk of dementia: every additional 10 micrograms of PM2.5 in the air raised incidence by 2%, mortality by 2.8%, and the total number of healthy life years lost by 2.2%. For ozone, the figures were the same or higher. Where there were enough green areas, this harmful effect became weaker or disappeared entirely.
The greatest benefit was observed at moderate and high levels of greening. In low-income countries, where pollution levels are higher and public green spaces are fewer, increasing them could be especially significant. Thus, expanding parks, tree-lined avenues and small public squares is not only an aesthetic issue, but also an accessible strategy for protecting brain health in an era of urbanization and population aging.
