National Oceanic and Atmospheric Administration (NOAA)

Participants

Winston Luke and Paul Kelley

  • Winston Luke
  • Paul Kelley
  • Steve Brooks

Instruments

ARL Instrument

NOAA's Air Resources Laboratory (ARL) will deploy a three channel, research grade detector for the simultaneous measurement of NO, NOX (NOX = NO + NO2), and NOY using the technique of ozone chemiluminescence. Low detection limits of 20-50 parts per trillion by volume at a 1s response time are achieved through photon counting the signals from low-noise red-sensitive photomultiplier tubes. High throughput pumping speeds and a high-output ozone generating electrode ensure enhanced sensitivity. NO2 is selectively converted to NO in a quartz photolysis cell illuminated with high power LEDs emitting near-UV radiation in a narrow wavelength range near 395 nm. NOY species are reduced to NO using a high temperature molybdenum converter heated to 375 degrees C.

Tekran mercury speciation front-end units looking to the west

Tekran Mercury Speciation

Looking towards the East with the Ship Channel in the background

Looking East towards Ship Channel

Continuous mercury speciation measurements at the Clinton Drive site at the western edge of the Ship Channel Industrial Complex

In 2006 we measured mercury speciation atop the Moody tower, and detected the largest mercury enhancements when the Moody tower was downwind of the ship channel. In 2009 we have located closer to the ship channel in hopes of further determining the local mercury emissions. Our instrumentation consists of Tekran model 2537a,1130, and 1135 for the determination of gaseous elemental mercury, reactive gaseous mercury, and particulate-bound mercury, respectively. Our measurements began April 15, 2009.

Objective

Continuous measurements of reactive nitrogen compounds will be used to characterize the magnitudes and types of emission sources and source regions in the Houston metropolitan area; to assess the freshness of these emissions using NOX/NOY ratios; to evaluate the degree of photochemical processing in transported plumes; to investigate the nature of O3-NOX relationships in background air, urban air, and emission plumes; and to bound the total NOY budget and assess the possible contributions of “missing” NOY species to the overall budget of reactive nitrogen in the area.

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