|HAMMOND, IAN - Western Kentucky University|
|MARTIN, RANDAL - Western Kentucky University|
|Silva, Philip - Phil|
|BAASANDORJ, MUNKH - Western Kentucky University|
Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 10/9/2017
Publication Date: 12/15/2017
Citation: Hammond, I., Martin, R.S., Silva, P.J., Baasandorj, M. 2017. Wintertime ambient ammonia concentrations in Northern Utah’s urban valleys. American Geophysical Union. Paper No. A53B-1444.
Technical Abstract: Many of the population centers in northern Utah are currently classified as non-attainment for PM2.5 and previous studies have shown ammonium nitrate to often be the largest contributor to the particulate mass. Measurements have shown several of the Wasatch Front cities and Cache Valley (UT/ID) consistently record some of the highest ambient ammonia (NH3) concentrations in the continental United States. As a part of the multi-organization 2017 Utah Winter Fine Particulate Study real-time NH3 concentrations were monitored in the Cache Valley. A Picarro model G2508 was to used collect 5-sec averaged concentrations of NH3, carbon dioxide (CO2), and methane (CH4) from January 16th to February 14th, 2017. Parts of three inversion events, wherein the PM2.5 concentrations approached or exceeded the National Ambient Air Quality Standards, were captured during the sampling period, including a 10-day event from January 25th to February 5th. Concentrations of all three of the observed species showed significant accumulation during the events, with NH3 concentrations ranging from below the detection limit (<0.5 ppb) to >70 ppb. Preliminary analysis suggested the temporal NH3 changes tracked the increase in PM2.5 throughout the inversion events; however, a one-day period of NH3 depletion during the main inversion event was observed while PM2.5 continued to increase. Additionally, a network of passive NH3 samplers (Ogawa Model 3300) were arrayed at 25 sites throughout the Cache Valley and at 11 sites located along the Wasatch Front. These networks sampled for three 7-day periods, during the same study time frame. Ion chromatographic (IC) analyses of the sample pads are not yet finalized; however, preliminary results show concentrations in the 10s of ppb and spatially correlate with previous studies showing elevated wintertime values.