To determine the distribution of lead in ambient air of Hamadan, 100
   samples were taken in different places from December 1997 until June 1998.

          The places of samples collection , were divided to three locations in
   street (high traffic, medium traffic and low traffic), gas pump stations and
   parking of cars. Portable sampling pump and filter cellulose were used to
   obtain samples. The samples transferred to laboratory and analyzed with
   atomic absorption spectrophtometry. The results showed the concentration
   of lead was 1mg/m³  in low traffic and 18 mg/m³    in high traffic places.
          The average concentration of lead in high traffic, medium traffic and
   low traffic were 7.99 , 4.63, 3.80 mg/m³ respectively and have significant
   difference among concentration of lead in low traffic places with gas
   stations and parking of cars.

          The average concentrations of lead in ambient air of Hamadan  was
   more than the standard limit (1.5 mg/m³ ) in ambient air recommended by 
   World Health Organization (WHO), and United States Environment Protection
   Agency (USEPA).