Update on Passive Ammonia Monitoring in the Four Corners and Oklahoma

Presented at the Four Corners Air Quality Task Force Meeting on May 9, 2007 in Farmington, New Mexico

Mark SatherU.S. EPA Region 6, Air Quality Analysis SectionDallas, Texas

Before we get to Ammonia we have to start with Ozone!Latest Comparison of 8-hour Ozone Data to the NAAQS

NW New Mexico ozone concentrations quickly climbed after 1997 ozone sampler deployment, going from an initial 1997-1999 8-hour ozone design value of 67 ppb to a 76 ppb design value for 2000-2002.

The 8-hour ozone concentrations have now decreased back to 70 ppb for the current 2004-2006 8-hour ozone design value.

Current sites to keep an eye on:Mesa Verde’s 8-hour ozone design value has recently increased to 73 ppb, and the 4 th highest 8-hour ozone concentration at the new Navajo Lake site was 79 ppb in 2006.Also keep eye on upcoming ozone NAAQS proposal.

1. NOx concentrations have increased at both Bloomfield and Substation.

2. NOx concentration increases are statistically significant at both sites (at 95% ci). The 2002-2006 five year mean is up 19% at Substation and up 42% at Bloomfield compared to the 1997-2001 five year mean.

3. NOx concentration increases have come from both mobile and industrial sources.

In order to keep ozone levels below the NAAQS, NOx emission controlsare being considered by the Four Corners Air Quality Task Force

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Substation Mean Morning NOx ConcentrationsJune-August weekday 0600-0900 LST

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Bloomfield Mean Morning NOx ConcentrationsJune-August weekday 0400-0700 LST

Now we get to Ammonia!

Ammonia Baseline Monitoring in Four Corners Area In September, 2005, the Interim Emissions Workgroup of the Four Corners Air Quality Task Force recommended that an ambient monitoring program for gaseous ammonia be initiated in the Four Corners area.

Purpose: To set a current baseline of ambient gaseous ammonia concentrations in the Four Corners area that can be compared to future monitored values in approximately 3-5 years after the implementation of NOx controls (e.g. NSCR) on oil and gas equipment.

The use of NSCR may increase ammonia emissions in the area, but these emissions have not been quantified and may or may not significantly affect visibility.

5 sites in Four Corners area plus one reference site in Oklahoma (the Cherokee Nation’s Stilwell site) are currently sampling and will run through 12/07.

Location of5 NH3

monitors

Stilwell, OK NH3 monitor

Ammonia Baseline Monitoring using Passive Samplers

To keep costs low for this initial screening study of ambient gaseous ammonia in the Four Corners area, Ogawa PSDs are being used.

NMED purchasing filters.

EPA Region 6 Houston Lab is in charge of preparing Ogawa PSDs for ammonia sampling, shipping PSDs to sites via Fed-Ex or UPS, and conducting IC analyses of filters.

3-week integrated sampling scheduled through 12/07.

Ammonia Passive Samplers - Pictures

Ammonia Baseline Monitoring using Passive Samplers (cont.)

EPA Region 6 Dallas is conducting initial analysis and interpretation of the passive ammonia data and distributing to NMED, NPS, Southern Ute Tribe, Cherokee Nation, Four Corners Task Force, EPA R6, EPA OAQPS, EC and any other interested parties.

Many thanks to the site operators who are doing excellent work!Joe Cotie – NMEDBrenda Sakizzie – Southern Ute TribeSylvia Oliva – Mesa Verde NPCherokee Nation Staff – Stilwell, Oklahoma

QA/QC of Passive Ammonia Data

Precision of Ogawa NH3 PSDs3-week samples; end dates 1/2-4/17, 2007

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Stilwell Site Ammonia Concentration Comparison (units in ppb)Year Time Period Nitrolux Ogawa PSD

2007 1/2-1/23 0.8 0.92007 1/23-2/13 1.6 1.72007 3/27-4/17 3.1 3.1