Current levels of air pollution have reduced life expectancy by an average of 1 year and 8 months worldwide.
Thus, for certain we know that exposure to air pollution reduces life expectancy, but knowing the average lifespan of particulate matter in air itself is presumably difficult in general, at least because air conditions are highly variable, unspecified and in addition, a detailed specification of the nature of the particulate under examination should be provided.
So, the question is not
posed very well, because the variability
of type, characteristics, concentrations, etc. of particulate matter in the air
are closely linked to the general and circumstantial local and environmental
conditions. Furthermore, they vary not only according to the type of
environment (urban, rural, overpopulated, desert, mountain, hilly, lake,
marine, arctic, equatorial, etc. etc.) but also with the altitude (height
helps!) and can be influenced by the long-range transport (also cross-border)
of air masses coming (in Italy e.g.) for example from the Saharan area (more
frequent in the summer months) and from Eastern European or Polar countries
(more frequent in the winter months). Furthermore, it is necessary to specify
which particulate matter we are referring to, since two main classes of
particulate matter can be identified, divided both by size and composition:
coarse particulate and fine particulate. Coarse particulate matter consists of
particles, including pollen and spores, with a diameter greater than 10 µm
(microns). Fine particles, on the other hand, have a diameter of less than 10
µm (microns), e.g. PM1=, PM5, PM2.5 . In any case, from an environmental point
of view, the interest and the measurements on the particulate matter suspended
in the air are mainly for local purposes, even if cross-border and therefore
international surveys cannot be neglected, especially for the radioactive,
toxic or particularly polluting contents that can present.
