Rubbertown Next Generation Emissions Measurement Demonstration Project

Abstract

Industrial facilities and other sources can emit air pollutants from fugitive leaks, process malfunctions and area sources that can be difficult to understand and to manage. Next generation emissions measurement (NGEM) approaches executed near facilities are enabling new ways to assess these sources and their impacts to nearby populations. This paper describes complementary uses of emerging NGEM systems in a Louisville, KY industrial district (Rubbertown), focusing on an important area air toxic, 1,3-butadiene. Over a one-year deployment starting in September 2017, two-week average passive samplers (PSs) at 11 sites showed both geospatial and temporal trends. At 0.24 ppbv annual average 1,3-butadiene concentration, a group of PSs located near facility fence lines was elevated compared to a PS group located in the community and upwind from facilities (0.07 ppbv average). Two elevated PS periods capturing emission events were examined using time-resolved NGEM approaches as case studies. In one event a 1.18 ppbv PS reading was found to be relatively localized and was caused by a multiday emission from a yet to be identified, non-facility source. In the other event, the airshed was more broadly impacted with PS concentrations ranging from 0.71 ppbv for the near-facility group to 0.46 ppbv for the community group. This case was likely influenced by a known emission event at an industrial facility. For both case studies, air pollutant and wind data from prototype NGEM systems were combined with source location models to inform the emission events. This research illustrates the power of applying NGEM approaches to improve both the understanding of emissions near sources and knowledge of impacts to near-source communities.

Keywords: 1,3-butadiene; NGEM; auto-GC; fenceline monitoring; fugitive emission; method 325.

Figure 1

Measurement sites for the first year of operation of the Rubbertown NGEM Demonstration Project. Yellow circles indicate primary measurement sites. Red squares indicate approximate locations of the example short-term SIS emissions events.

Figure 2

NGEM systems located at (a) S1, LMAPCD monitoring shelter housing auto-GC and other instruments, (b) one of two EPA SPod FSs with ACGS, (c) MiTAP field GC (off frame low), (d) PS at S1 (left circle) and close-up of the PS deployment system (center circle) and, (e) PS at S10 illustrating an elevated deployment in a public area (right circle).

Figure 3

PS-determined 1,3-butadiene concentrations: (a) By monitoring site with all 26 PS sampling periods grouped [6 periods for S11], (b) by PS sampling period with all 10 monitoring sites grouped, (c) by period with three sites closest to 1-3 butadiene-relevant facilities grouped (near-facility group), and (d) by period with two farthest sites and an upwind site grouped (community/upwind group). The box whiskers extend to the largest measurement <1.5 times the interquartile range. Blue markers indicate means with 95% confidence intervals calculated by non-parametric bootstrap. The red box and circles in (a) and (b) indicate the highest reading at S1 during period 12 and highest readings at S5 and S8 during period 13, respectively.

Figure 4

Time-resolved measurements of SIS1 event with SPod data averaged to five minutes. Single side horizontal error bars in GC data indicate the temporal extent of air sampling. Due to observed concentrations well beyond instrument calibration ranges, the GC data are considered approximate.

Figure 5

(a) S1 SPod source direction indicator (SDI) plot for 22:00 on 2/25/2018 to 11:00 on 2/26/2018 with concentric circles representing wind speed in m/s and color bar SPod PID, and (b), (c), and (d) showing 99 back trajectory paths each for the five-minute BTM runs for 23:05 on 2/25/2018, 2:05 on 2/26/2018, and 5:25 on 2/26/2018, respectively, the highest concentrations of Figure 4. The concentric red boxes represent the near-optimal trial source location from TCTA with the inner box approximating the defined source areas for the TCTA calculation.

Figure 6

Time-resolved observations of SIS2 with SPod readings (five-minute average) plotted on the secondary ordinate axis. Single side horizontal error bars in GC data indicate the temporal extent of air sampling. The SPod data are non-speciated, and do not directly correspond to 1,3-butadiene.

Figure 7

BTMs of SIS2 on 6/19/2018: (a) expanded view of 5:55 model from S1 (b) full view of 5:55 model from S1, (c) SPod SDI plot from S1 (top) and S8 (bottom), (d) expanded view of 6:40 model from S1, and (e) expanded view of 12:05 model from S8 with QUIC model optimized location SIS2b’ indicated. The concentric red boxes represent the near-optimal trial source location from TCTA, with the inner box approximating the defined source areas for the TCTA calculation.

Figure 8

(a) Comparison of one-minute time average SPod readings from S8 (bottom panel) with QUIC model simulated emission time series from SIS2a (red dashed trace top panel), SIS2b’ (blue trace top panel), and a composite result of SIS2a and SIS2b’ (middle panel), (b) frame of QUIC model video (Video SM5) at 10:15 on 6/19/2018.