**Acknowledgements**

oxidative damage in proteins, lipids and DNA, interferes with DNA repair and affects cellular

Metals enter into the respiratory system adhered to particulate matter, and by this route they reach the systemic circulation. In the blood metals are attached to proteins or ionized entering into the different organs and cells producing a variety of outcomes. The chemical characteris‐ tics of the inhaled metals, the length of the exposure, the route, and the physiology of each organ will determinate the metabolism, the affected functions and the possible manifestations, which are resumed in Figure 1. Some metals interact with enzymes inhibiting its actions by the interaction of the metal with the SH group of the enzyme or by displacement of an essential metal cofactor; another interference mechanism is the inhibition of the synthesis of the enzyme, indirectly altering the systemic function; the binding of the metal by certain cytosolic proteins may modify its toxicity. Also metals may interact directly with the components of the cell, and may be accumulated in the lysosomes, or damaging the mitochondria and inhibiting respira‐ tory enzymes leading to cell death. A direct interaction with DNA may produce gene muta‐ tions, chromosome aberrations or aneuploidy; these changes could pave the way to

**Figure 1.** Interaction of metals in particular matter that enters into the respiratory system inducing inflammation, oxi‐

dative stress and genotoxicity. The sources and possible outcomes are resumed.

signaling pathways and cells proliferation [230].

proliferation and cancer development [231].

**3. Conclusion**

590 Current Air Quality Issues

Authors thank Alejandra Núñez-Fortoul for reviewing the final English version.
