Reactive nitrogen partitioning and its relationship to winter ozone events in Utah

Abstract

Abstract. High wintertime ozone levels have been observed in the Uintah Basin, Utah, a sparsely populated rural region with intensive oil and gas operations. The reactive nitrogen budget plays an important role in tropospheric ozone formation. Measurements were taken during three field campaigns in the winters of 2012, 2013 and 2014, which experienced varying climatic conditions. Average concentrations of ozone and total reactive nitrogen were observed to be 2.5 times higher in 2013 than 2012, with 2014 an intermediate year in most respects. However, photochemically active NO x (NO + NO 2 ) remained remarkably similar all three years. Nitric acid comprised roughly half of NO z (≡ NO y − NO x ) in 2013, with nighttime nitric acid formation through heterogeneous uptake of N 2 O 5 contributing approximately 6 times more than daytime formation. In 2012, N 2 O 5 and ClNO 2 were larger components of NO z relative to HNO 3 . The nighttime N 2 O 5 lifetime between the high-ozone year 2013 and the low-ozone year 2012 is lower by a factor of 2.6, and much of this is due to higher aerosol surface area in the high-ozone year of 2013. A box-model simulation supports the importance of nighttime chemistry on the reactive nitrogen budget, showing a large sensitivity of NO x and ozone concentrations to nighttime processes.

An Odd Oxygen Framework for Wintertime Ammonium Nitrate Aerosol Pollution in Urban Areas: NOx and VOC Control as Mitigation Strategies

“…These results are compared to observations of trace gas species from the recent Uintah Basin Winter Ozone Study, where a major PCAP in January 2013 led to elevated levels of O 3 (Ahmadov et al, 2015;Edwards et al, 2014). Measurement techniques for both campaigns are described in detail in Text S1 (Lee et al, 2014;Liao et al, 2017;Wild et al, 2014;Wild et al, 2016).…”

Local Arctic Air Pollution: A Neglected but Serious Problem

“…At southerly latitudes, recent observations from regions of oil and natural gas extraction in northern Utah showed very large episodic wintertime enhancements in surface ozone. These events, driven mainly by photochemical processes (available sunlight), are also a result of reduced dry deposition and high albedo due to snow cover, coupled with shallow boundary layer heights and calm conditions (Ahmadov et al, 2015;Edwards et al, 2014;Schnell et al, 2016;Wild et al, 2016). Emissions of VOCs from extractions activities have been shown to be key drivers of ozone production during such events, with large contributions from aromatic VOCs (Ahmadov et al, 2015).…”

ClNO2 Yields From Aircraft Measurements During the 2015 WINTER Campaign and Critical Evaluation of the Current Parameterization

“…Ambient ClNO 2 was first observed off the coast of Texas in 2006 (Osthoff et al, ). It has since been measured from ship‐, ground‐, and aircraft‐based platforms in both continental and coastal/marine environments throughout North America (Edwards et al, ; Faxon et al, ; Kercher et al, ; Kim et al, ; Mielke et al, , ; Osthoff et al, ; Riedel et al, , ; Thornton et al, ; Wild et al, ; Young et al, ), Europe and the United Kingdom (Bannan et al, , ; Phillips et al, , ; Reyes‐Villegas et al, ), and Asia (Liu et al, ; Tham et al, , , ; X. Wang, Wang, Xue, et al, ; T. Wang et al, ; Z. Wang, Wang, Tham, et al, ; H. Wang et al, ; X. Wang et al, ; Yun et al, ). Reported mixing ratios range from a few parts per trillion (pptv) to a maximum of 4,700 pptv (1‐min average), measured in December 2013 in Southern China (T. Wang et al, ).…”