# Presentation: 207146

## Plans for a Speciated Ambient Mercury Monitoring Network

- Presented at the
- 2006 National Air Quality Conference
- Presented by
- Kevin A. Cavender
- EPA/OAQPS
- October 6, 2005

## Overview

- Why monitor mercury?
- Current mercury monitoring
- Why do we need speciated data?
- Technologies
- Network strategy
- Questions and answers

## Why Monitor Mercury?

- Mercury is a persistent bioaccumulative toxic (PBT)
- Impairs neurological development in babies and young children
- Main pathway is fish consumption

## Mean Mercury Concentrations for Top 24 Types of Fish Consumed in U.S. Commercial Seafood Market 

- Source: Carrington and Bolger, 2002

## CAIR and CAMR Accountability

- The Clean Air Interstate Rule and the Clean Air Mercury Rule (CAIR, CAMR) will reduce mercury emissions from coal-fired power plants.
- Under several mandates such as the Government Performance and Results Act (GPRA), and the Program Assessment Rating Tool (PART), the EPA will be expected to assess reductions in deposition and risk due to these rules.
- Tracking progress and results is a critical step in improving air quality management programs (National Research Council, “Air Quality Management in the United States”, 2004).
- Determine if additional emission reductions are needed to protect human health and ecosystem welfare.
- Show we know what we are doing

## CMAQ Estimated 2001 Total Mercury Deposition

## CMAQ Estimated Reduction in Total Mercury Deposition Due to CAIR/CAMR (2020)

## Improve Mercury Modeling

- Current transport and deposition model estimates are very uncertain due to lack of data to validate models
- Data on speciated ambient mercury needed to validate these models.

## Mercury Deposition Network

- Started in 1995
- Wet deposition in rain and snow
- Unspeciated
- No dry deposition (no data to estimate it)
- Broad geographic coverage (including Canada and Mexico), though fewer sites in cities and west of the Mississippi River
- Part of NADP, individual sites sponsored by Federal, State, and local organizations
- http://nadp.sws.uiuc.edu/mdn/

## Total Mercury Wet Deposition, 2003

## Current Gaps in Mercury Monitoring

- No dry deposition monitoring (or surrogate)
- Current direct dry deposition methods not practical for routine network
- MDN coverage poor in western states
- Current MDN not adequate for tracking impact of CAMR

## Recommendations for Improving Mercury Monitoring

- 	Develop method to routinely measure or estimate dry deposition
- Current dry deposition methods are too expensive/intensive for routine use
- ORD working on improving methods to allow for limited deployment for model development
- Deploy network of currently available continuous total/speciated ambient air mercury monitors as surrogate
- Models to be developed that relate these speciated air measurements to dry deposition

## Why do We Need Speciated Data?

- Direct dry deposition measurements are not practical at this time.
- Speciated mercury data needed to estimate dry deposition
- Dry deposition can be from 0.25 to 3 times wet deposition, depending on location
- ~98% of total ambient mercury is elemental mercury, yet deposition rates are driven by particulate and oxidized Hg

## Speciated Ambient Mercury Methods

- Continuous monitors
- Tekran
- Others?
- Manual Method

## Tekran Continuous Speciated Ambient Mercury Monitor

- Provides semi-continuous measurements of Hgo, Hg(II), and Particulate Hg
- Fairly high capital cost
- Lower operating costs
- Lots of data – 1 sample/3hours

## Manual Method

- Same principle as continuous, but analysis occurs back in the lab
- Provides integrated measurements of Hgo, Hg(II), and Particulate Hg
- Low capital cost
- Higher operating costs
- Lower data resolution (1 in 3 days, 1 in 6 days, etc.)

## Looking Beyond Current Methods

- Looking for other vendors to enter the market
- Push for new or improved methods that –
- Reduce costs
- Improve performance
- Less intensive

## Network Strategy

- Work with NADP to expand MDN to include speciated ambient mercury monitoring
- Build infrastructure and support for network operations
- Partner with other Federal, state, and local agencies to “sponsor” sites
- Mix of continuous and manual sites
- “Build it and they will come” approach

## Questions