A Comparison of Two Collectors for Monitoring Precipitation Chemistry

Abstract

Comparison of event-based precipitation collected during 1 year showed that samples from a Yankee Environmental Systems collector had significantly higher volume, higher concentrations, and higher deposition of all ions analyzed except PO 4 3− and NH 4 + compared to samples collected simultaneously with an Aerochem Metrics collector.

A Comparison of Wet Deposition Collectors at a Coastal Rural Site

“…The current study corroborates the findings of the previous published collector comparisons: A more sensitive precipitation sensor is associated with relatively small but sometimes statistically significant differences in solute concentrations (Kelly et al 2012;Sirois et al 2000, Wetherbee et al 2009. This bias was most pronounced when comparing concentrations in individual event-based, or periodic samples, but can still be important for some solutes at the weekly or annual scale.…”

“…While the studies all generally agree that bias occurs, the magnitude of the bias for NO 3 − , NH 4 + , and SO 4 2− differs among studies. For example, the present study and Kelly et al (2012) found the smallest effect for NH 4 + while Wetherbee et al (2009) found the largest effect for NH 4 + . While not measured in the current study, these other studies reported even larger effects on the base cations than the components of acid deposition.…”

“…Thus, the effects observed in this study could be due to the background variability in rain chemistry and not due to collector effects at all. Kelly et al (2012) compared the ACM to the Yankee Environmental Systems collector which is similar to the N-CON. They found significantly lower concentrations in the ACM collector.…”

“…The main goal of this research was to test if the catch efficiency and precipitation chemistry differed between the ACM and N-CON collectors at a site with coastal influence on an event basis. Recent research at non-coastal sites has suggested that the ACM collectors respond differently to precipitation compared to the N-CON (e.g., Wetherbee et al, in review) and other collectors (Kelly et al 2012). In part, this may be related to the fact that the number of lid openings, as well as the number of hours with the lid open, was at least double for the N-CON collector during testing by the NADP program (Wetherbee et al, in review).…”