Atmospheric Polycyclic Aromatic Hydrocarbons (PAH) at a Point Source of Emissions. Part B: PAH Emissions Reduction at a Horizontal Stud Soderberg Plant at Jonquiere, Quebec, Canada and the Evolution of B[a]P in Ambient Urban Air

Abstract

In Quebec, Canada the production of primary aluminum using the Horizontal Stud Soderberg process is a significantsource of atmospheric emissions.

Since 1984, in the area surrounding a Soderberg plant at Jonquiere, Quebec, regular monitoring of the ambient air has made tt possible to follow the evolution of PAH levels in urban areas. BlalP is used as an indicator of total PAH. The ambient air is sampled twice a week using Hi-Vol samplers to collect particulate PAH on glass-fiber filters.

From 1984 to 1990, there has been a 67 percent reduction in PAH emissions at the Jonquiere plant. The two factors contribu1ing to this situation are the shutdown of certain Soderberg production units and an ongoing program of reduction of PAH emissions into the atmosphere. Annual geometric mean ambient levels of 1 to 3 ng/m³ (B[a]P) for 1990 have been reported at sampling stations affected by prevailing winds wtthin a 6 km radius of the emissions source.

This paper shows the representativeness of the PAH sampling network in the area surrounding the industrial sije. There is a general trend towards lower levels of B[a]P in air coincident with the emissions reduction program. Averification of the data shows that they are not normally distributed but are highly right-skewed and generally follow lognormal distributions.