JUSTIFICATION 

Particles smaller than 10 micrometers (PM₁₀) serve as condensation nuclei for water and other vapors, so that these adsorb heavy metals and microbiological agents that, when inhaled, are transported into the lungs. The health effects depend on the concentration of particles to which populations are exposed. The most important impacts are respiratory infections, allergies and asthma. These particles derive from natural or anthropogenic activities or processes such as construction, diesel motor vehicles, forest fires, some manufacturing industries and suspended street dust.