Mercury Vapur

INTRODUCTION
Pollutants or toxic materials when dispersed in air, generally form mixtures, tend to alter their physical properties, such as density, viscosity, enthalpy, and later are indistinguishable from those of clean air. While dispersed in the air, all molecules of a given compound are essentially equivalent in their size and probabilities of contact with ambient surfaces, respiratory tract surfaces, and contaminant collectors or samplers. To study in detail Diesel particulate matter and mercury vapour are dealt below for better understanding.
DIESEL PARTICULATE MATTER (DPM)
Diesel exhaust has three major sources namely mobile sources (on-road vehicles), stationary area sources (industrial sources) and stationary point sources. Diesel

The RBCs contain about 9 times more mercury than plasma. Hg is metabolized to Hg++ . Both forms react with phosphate, amino and carboxyl, thus it inhibits enzymes, disrupts cell membranes, damages structural proteins and affects the genetic code in nucleic acids. Hg enters the brain as a complex structurally similar to methionine (a common carrier in the membranes of the blood-brain barrier) and exists in this form until it penetrates to the ribosomes and the site of initiation of protein synthesis. Blood-brain ratio of concentrations is dose-dependent (i.e., high blood mercury concentration, then brain concentrations are disproportionately higher). In the mature nervous system, damage is limited to specific focal areas such as the granule cells of the cerebellum and neurons in the interstices of the visual cortex. In the developing brain, Hg causes incomplete or abnormal migration of neurons to the cerebellar and cerebral cortices, accompanied by diffuse astrocytosis and deranged cortical organization of the cerebrum. Other effects in brain (and elsewhere). High affinity to SH groups thus it inhibits any SH-containing enzymes in brain, including synthesis of proteins, especially at transfer RNA and peptide elongation steps; Hg causes depolymerization of microtubules (mitotic spindle) resulting in adverse effects on cell division, such as of granule cells in the developing cerebellum. It is not clear if these effects are from Hg form, Hg++ form (after Hg has been demethylated), or a combination of the