Effects on Network Photometers Ozone Transport Commission - - PowerPoint PPT Presentation

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Effects on Network Photometers Ozone Transport Commission - - PowerPoint PPT Presentation

Aug 25, 2022 192 likes •342 views

O 3 Scrubber Upgrade & Inlet Height Effects on Network Photometers Ozone Transport Commission OTC/MANE-VU Committee Meeting September 10, 2015 Washington, DC Will Ollison 1220 L Street, NW Washington, DC 20005 - 4070 www.api.org

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SLIDE 1

O3 Scrubber Upgrade & Inlet Height Effects on Network Photometers

Ozone Transport Commission OTC/MANE-VU Committee Meeting September 10, 2015 Washington, DC Will Ollison

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 1

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SLIDE 2

Upgraded O3 Photometer & Inlet Height Measurements

  • Current network O3 photometers are subject to positive

interference bias (Hg, H2O, Aryl VOCs) raising O3 design values Spicer et al. JAWMA 60: 1353–1364 (2010); Johnson et al. JAWMA 64: 360-71 (2014).

  • Nitric oxide-gas phase titration (NO-GPT) O3 scrubber upgrades

(http://www.twobtech.com/model_GPT.htm) raise accuracy (Note #40 http://www.twobtech.com/products.htm) and NAAQS compliance Ollison et al. JAWMA 63: 855–863 (2013).

  • U.S. O3 monitor inlet heights average 5.4 meters (Richard

Wayland–personal communication); but it’s thought that 2 meter inlets better (1) approximate outdoor nose level exposure and (2) appear to better comply with ambient O3 NAAQS.

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 2

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SLIDE 3

Distribution of O3 Compliance Monitor Inlet Heights (m)

Richard Wayland – Personal Communication

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 3

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SLIDE 4

Westport, CT Upgraded O3 Monitor and Inlet Height Study

  • 1. A collocated NO-scrubbed upgraded Teledyne-API T400

photometer, with alternate 5-min sampling (4-min before 6/29/15) at 2m and 6.2m inlets, is compared to the conventional Westport site TAPI T400.

  • 2. Measured O3 levels adjusted daily for relative monitor drift.
  • 3. Preliminary findings:
  • Upgraded NO-scrubbed photometer O3 peaks decrease

with inlet height during stable meteorological conditions

  • Collocated upgraded NO-scrubbed photometer O3

peaks generally decrease with respect to conventional photometer values.

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 4

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SLIDE 5

Westport, CT Monitoring Site Google Maps 41.118201, -73.336713

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 5

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SLIDE 6

Westport, CT Monitoring Site Google Maps 41.118201, -73.336713

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 6

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SLIDE 7

Westport, CT Monitoring Site Alan Leston – Personal Communication

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 7

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SLIDE 8

2 Meter Westport Inlet Alan Leston – Personal Communication

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 8

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SLIDE 9

6.2 Meter Westport Inlet Alan Leston – Personal Communication

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 9

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SLIDE 10

Rolling 8-Hour O3 Values (ppb) Collocated 6.2m Inlet Height

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 10

  • 5

5 10 15 20 25 30

  • 40
  • 20

20 40 60 80 100

6/16/15 0:00 6/17/15 0:00 6/18/15 0:00 6/19/15 0:00 6/20/15 0:00 6/21/15 0:00 6/22/15 0:00 6/23/15 0:00 6/24/15 0:00 6/25/15 0:00 6/26/15 0:00 6/27/15 0:00 6/28/15 0:00 6/29/15 0:00 6/30/15 0:00 7/1/15 0:00 7/2/15 0:00 7/3/15 0:00 7/4/15 0:00 7/5/15 0:00 7/6/15 0:00 7/7/15 0:00 7/8/15 0:00 7/9/15 0:00 7/10/15 0:00 7/11/15 0:00 7/12/15 0:00 7/13/15 0:00 7/14/15 0:00 7/15/15 0:00 7/16/15 0:00 7/17/15 0:00 7/18/15 0:00 7/19/15 0:00 7/20/15 0:00 7/21/15 0:00 7/22/15 0:00 7/23/15 0:00 7/24/15 0:00 7/25/15 0:00 7/26/15 0:00 7/27/15 0:00 7/28/15 0:00 7/29/15 0:00 7/30/15 0:00 7/31/15 0:00 8/1/15 0:00 8/2/15 0:00 8/3/15 0:00 8/4/15 0:00 8/5/15 0:00 8/6/15 0:00 8/7/15 0:00 8/8/15 0:00 8/9/15 0:00 8/10/15 0:00 8/11/15 0:00 8/12/15 0:00 8/13/15 0:00 8/14/15 0:00 8/15/15 0:00 8/16/15 0:00 8/17/15 0:00 8/18/15 0:00 8/19/15 0:00 8/20/15 0:00 8/21/15 0:00 8/22/15 0:00 8/23/15 0:00 8/24/15 0:00 8/25/15 0:00 8/26/15 0:00 8/27/15 0:00

8h Adj O3 8h Adj O3 2m 8h Adj O3 6m 8h Adj O3-6m Diff

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SLIDE 11

Rolling 8-Hour O3 Values (ppb)

Measured at 2m Inlet Height

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 11

  • 5

5 10 15 20 25 30

  • 40
  • 20

20 40 60 80 100

6/16/15 0:00 6/17/15 0:00 6/18/15 0:00 6/19/15 0:00 6/20/15 0:00 6/21/15 0:00 6/22/15 0:00 6/23/15 0:00 6/24/15 0:00 6/25/15 0:00 6/26/15 0:00 6/27/15 0:00 6/28/15 0:00 6/29/15 0:00 6/30/15 0:00 7/1/15 0:00 7/2/15 0:00 7/3/15 0:00 7/4/15 0:00 7/5/15 0:00 7/6/15 0:00 7/7/15 0:00 7/8/15 0:00 7/9/15 0:00 7/10/15 0:00 7/11/15 0:00 7/12/15 0:00 7/13/15 0:00 7/14/15 0:00 7/15/15 0:00 7/16/15 0:00 7/17/15 0:00 7/18/15 0:00 7/19/15 0:00 7/20/15 0:00 7/21/15 0:00 7/22/15 0:00 7/23/15 0:00 7/24/15 0:00 7/25/15 0:00 7/26/15 0:00 7/27/15 0:00 7/28/15 0:00 7/29/15 0:00 7/30/15 0:00 7/31/15 0:00 8/1/15 0:00 8/2/15 0:00 8/3/15 0:00 8/4/15 0:00 8/5/15 0:00 8/6/15 0:00 8/7/15 0:00 8/8/15 0:00 8/9/15 0:00 8/10/15 0:00 8/11/15 0:00 8/12/15 0:00 8/13/15 0:00 8/14/15 0:00 8/15/15 0:00 8/16/15 0:00 8/17/15 0:00 8/18/15 0:00 8/19/15 0:00 8/20/15 0:00 8/21/15 0:00 8/22/15 0:00 8/23/15 0:00 8/24/15 0:00 8/25/15 0:00 8/26/15 0:00 8/27/15 0:00

8h Adj O3 8h Adj O3 2m 8h Adj O3 6m 8h Adj O3-2m Diff

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SLIDE 12

EPA Inlet Height Considerations

The 2006 Ozone CD notes, based on the information derived from non-urban studies, that the degree of atmospheric stability is important as “there was a decrease of about 20% in going from a height of 4m down to 0.5m above the surface during stable conditions, but O3 decreased by only about 7% [i.e., by about 5 ppb at 70 ppb O3] during unstable conditions.” While there is some information indicating decreasing ozone concentration with decreasing monitor probe height, there are too few studies available at this time with the appropriate data to develop a reasonable quantitative relationship for adjusting

  • zone data (or design values) in urban areas.

Richard Wayland–Personal Communication

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 12

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SLIDE 13

Recommendations

  • EPA regulatory staff recognize increasing vertical O3 gradients

above 2m and the need to adjust monitored values to better reflect actual human outdoor exposures at this level.

  • The Westport data show a persistent, although meteorologically

variable, positive O3 gradient upwards from the 2m AGL values thought to be more representative of outdoor human exposures than current monitor inlet heights in the 4m to 6m range.

  • SLTs should consider moving O3 monitoring inlets to the 2m level

now as a timely, practical remedy of this positive O3 gradient bias, given EPA’s acknowledged lack of adequate gradient data to downward adjust high inlet urban O3 design values appropriately.

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org 13