The report gives results of an evaluation of the potential environmental effects of air emissions from the production of urea. Urea production in the U.S. was 3.45 million metric tons in 1975. Major products were urea solution (38%), granulated solid material (53%), and prilled solid material (9%). Over 75% of the urea produced is consumed in fertilizers. Both ammonia and particulates are released to the atmosphere during its manufacture. Major emission points are the evaporator, prilling tower, and granulator. The evaporator has the largest emission factor for ammonia, 1.73 g/kg; the prill tower has the largest for particulates, 3.2 g/kg. Emissions from the evaporator and granulator are normally controlled by scrubbers; prill tower emissions are not controlled. Source severities were determined to evaluate potential environmental effects: they were between 10 and 1 for ammonia emissions from the prill tower and for particulate emissions from the evaporator, granulator, and prill tower. (Source severity is the ratio of the average maximum ground level concentration of an emission species to the ambient air quality standard (particulates) or (for ammonia) to a reduced threshold limit value.)

"November 1977." "EPA Task Officer: Ronald A. Venezia." Contract 68-02-1874, ROAP 21AXM-071, Program element 1AB-15, sponsored by Industrial Environmental Research Laboratory. Office of Energy, Minerals, and Industry, Triangle park, N.C.