Partial neutralization of rain by seaspray: the case of Recôncavo, Bahia-Brazil.

In the Recôncavo of Bahia (located between 12 degrees 33' and 13 degrees 10'S and 38 degrees 00'and 39 degrees 00'W), there are significant discharges of SO(2) and NO(x) due to local, industrial and urban activities. The incoming air masses from the Atlantic Ocean are enriched with seaspray, which neutralizes part of the rain acidity. The extent of seaspray neutralization of rain acidity was quantified in four sites of the region, each with different loads of seaspray. Rain samples were obtained daily at the same time, integrating the precipitation of the previous 24h, using wet-only collectors and analyzed for pH by potentiometry and for sodium by flame photometry. The amount of rain acidity in Recôncavo neutralized by seaspray ranged from <1% up to 88% and depended on the site. On average, neutralization ranged from 5% to 18%.