Acidic precipitation at a site within the northeastern conurbation

Abstract

Rain and snow were collected in plastic beakers either manually or with a Wong sampler during 58 precipitation events in 1974 at Yonkers, New York approximately 24 km north of the center of New York City. Determinations were made of total dissolved ionic species, free H ions, total H ions, sulfate, nitrate, chloride, and fluoride. Conductivity measurements ranged from 6.8 to 162 gmhos, pH from 3.4 to 4.9, total acidity from 36 to 557 μeq 1⁻¹ sulfate from less than 1 to 20 mg 1⁻¹, nitrate from less than 1 to 14 mg 1⁻¹, and chloride from less than 1 to 7 mg 1⁻¹. All fluoride concentrations were less than 0.1 mg 1⁻¹.

The results indicate that precipitation at this suburban location adjacent to New York City is consistently acidic and contains concentrations of sulfate, nitrate, and chloride which are similar to values found for other locations in the northeastern United States. Positive correlations were found between nitrate and sulfate concentrations and acidity suggesting that the atmospheric contaminants, SO₂, and NO₂ are causally-related to the occurrence of acidic precipitation. Further research will be necessary to clarify the relative influence of natural and man-made sources of N and S compounds and the contributions of gaseous and particulate contaminants in the atmosphere to the acidity of precipitation at this location.