SPATIAL AND TEMPORAL VARIATIONS OF ATMOSPHERIC DEPOSITION IN INTERIORAND COASTAL CONNECTICUT

Both wet and dry deposition fluxes of sulfur, nitrogen, and phosphorus were estimated at three monitoring stations in Connecticut, one inlan d near the Connecticut-Massachusetts border and two along the Connecti cut coastline of Long Island Sound. Three years of data, from 1991 thr ough 1993, were analyzed and are reported in this paper. The total ann ual deposition ranged from 1.27 to 1.58 gm(-2) for sulfur, 0.8 to 0.85 gm(-2) for nitrogen, and 3.81 to 4.69 mg m(-2) for phosphorus. More t han 90% of the phosphorus and about two-thirds of the sulfur and nitro gen were deposited in wet form. The estimated wet deposition quantitie s were all higher in summer, indicating a higher scavenging efficiency of rainfalls. The dry deposition quantities were higher for particles but lower for gases during the summer seasons. While there were no si gnificant differences in wet deposition among the three monitoring sta tions, spatial gradients in atmospheric concentration and dry depositi on, especially for sulphur, were detected with higher values to the so uthwest industrial area. Although more sites might be needed to pinpoi nt the sources of the pollutants, one station is sufficient for a reli able estimation of the overall deposition. The strong episodic nature of the deposition quantities, however, demands more frequent than dens er sampling in the area for long-term monitoring. Also, since the week ly deposition quantities were all strongly positively skewed, more des criptive statistics in addition to the mean values are recommended in data reports. Copyright (C) 1996 Elsevier Science Ltd.