NO_y lifetimes and O₃ production efficiencies in urban and power plant plumes: Analysis of field data

Abstract

Abstract. In an effort to describe and characterize power plant plumes in the Nashville region, emissions from a small power plant (Gallatin) and a large power plant (Paradise) were examined using data obtained on the Department of Energy G-1 airborne sampling platform. Observations made on July 3, 7, 15, 17, and 18, 1995, were compiled, and a kinetic analysis of the chemical evolution of the power plant plumes was performed. Analysis of the power plant plume data revealed a very active photochemistry, as had been determined previously for the urban plume. Ozone production efficiencies (OPE), defined as the number of molecules of 03 formed per NOx molecule consumed, were found to be 3 for Gallatin and 2 for Paradise. Lifetimes for NOx (2.8 and 4.2 hours) and NOy (7.0 and 7.7 hours) were determined for Gallatin and Paradise, respectively. These NOx and NOy lifetimes imply rapid loss of NO z (NO•. is assumed to be primarily HNO3). Lifetimes for NOz are calculated to be 3 and 2.5 hours for Gallatin and Paradise, respectively. A sensitivity analysis indicates that the Gallatin NO z lifetime could be as long as 5 hours, bringing it into agreement with the value determined for the Nashville urban plume. It is unlikely that the Paradise NO• lifetime is as long as 4 hours. If NO z loss is attributed to dry deposition, a 3 hour lifetime implies a deposition velocity greater than 10 cm s -1, which is much faster than expected based on accepted theory. Possible reasons for this discrepancy are discussed.

Ozone production in the New York City urban plume

“…Of particular concern is depletion of NOy due to dry deposition, which will increase the value of CO/NOv as was sometimes observed to happen in the Nashville, Tennessee urban and power plant plumes [Gillani et al, 1998a;Nunnermacker et al, 1998Nunnermacker et al, , 2000. The use of a regression method partially eliminates that concern as the regression slope is only sensitive to increases above background and is therefore not affected by deposition of background NOy.…”

SCIAMACHY tropospheric NO<sub>2</sub> over Switzerland: estimates of NO<sub>x</sub> lifetimes and impact of the complex Alpine topography on the retrieval

“…From a pollution point of view, all regions are similar to the conditions encountered over the Swiss Plateau. For an assumed temperature of 298 K and based on OH concentrations taken from the BERLIOZ and the SLOPE96 campaigns with noontime values of (4-8)×10 6 cm −3 (Volz- Mihelcic et al, 2003) and (7-10)×10 6 cm −3 (Volz-Thomas and Kolahgar, 2000), respectively, the resulting mean daytime NO x lifetimes in summer are estimated to be 4.6 h and 3.0 h. These data have been deduced from campaigns in the U.S. (Spicer, 1982;Ryerson et al, 1998;Nunnermacker et al, 2000;Sillman, 2000) and in the Swiss Plateau (Dommen et al, 1999), from GOME NO 2 VTCs over Germany (Beirle et al, 2003) and from the GEOS-CHEM model (Fig. 7).…”

“…The seasonal mean lifetimes are summarised in Table 1 -from measurements in urban plumes: Boston: 5.5 h (Spicer, 1982), Nashville: 2.0 h (Nunnermacker et al, 2000), Zurich: 3.2 h (Dommen et al, 1999),…”

Evolution of NO<sub><i>x</i></sub> in the Denver Urban Plume during the Front Range Air Pollution and Photochemistry Experiment

“…Neuman et al (2009) reported the lifetime of HNO 3 to dry deposition was 14 hours in Houston. Nunnermacker et al (2000) calculated an NO z lifetime in the Nashville urban plume of 8.7 hours, although they acknowledge that this short lifetime would correspond to an unexpectedly fast deposition velocity 30 of 6.7 cm s -1 for HNO 3 . In a pine forest environment, Farmer and Cohen (2008) calculated a deposition velocity of HNO 3 of 3.4 cm s -1 .…”