MEASUREMENTS OF ATMOSPHERIC HNO3, HCL AND ASSOCIATED SPECIES ON A SMALL NETWORK IN EASTERN ENGLAND

Measurements of gaseous HNO3, HCl and NH3 and particulate NO3-, SO42-, Cl- and NH4+ have been made at a small network of sites in eastern England using sampling intervals from 3 h to 7 days. Both HCl and HNO3 are spatially rather uniform, with some variation apparently due to spatial variations in NH3, which stoichiometrically exeeded the sum of both gaseous acids. Mean concentrations of NH3, HCl and HNO3 between February 1987 and January 1988 were 1.90, 0.67 and 1.01 μg m-3, respectively. Pollution roses revealed low NH3 concentrations, and high associated HCl and HNO3 with winds from the North Sea. HCl, but not HNO3 showed an appreciable elevation in concentration on the sector NW from our site, which we speculate may be due to the large capacity of coal-fired power stations in this upwind sector. Three-hourly data have been examined for diurnal effects and its is concluded that nocturnal formation of NO3- is occurring. © 1990.