Effects of Evaporative Emissions Control Measurements on Ozone Concentrations in Brazil

In this work, the possible benefits obtained due to the implementation of evaporative emissions control measures, originating from vehicle fueling processes, on ozone concentrations are verified. The measures studied are: (1) control at the moment when the tank trucks supply the fuel to the gas stations (Stage 1); (2) control at the moment when the vehicles are refueled at the gas stations, through a device installed in the pumps (Stage 2); (3) same as the previous control, but through a device installed in the vehicles (ORVR). The effects of these procedures were analyzed using numerical modeling with the VEIN and WRF/Chem models for a base case in 2018 and different emission scenarios, both in 2018 and 2031. The results obtained for 2018 show that the implementation of Stages 1 and 2 would reduce HCNM emissions by 47.96%, with a consequent reduction of 19.9% in the average concentrations of tropospheric ozone. For 2031, the greatest reductions in ozone concentrations were obtained with the scenario without ORVR, and with Stage 1 and Stage 2 (64.65% reduction in HCNM emissions and 31.93% in ozone), followed by the scenario with ORVR and with Stage 1 and Stage 2 (64.39% reduction in HCNM emissions and 32.98% in ozone concentrations).

Direct Measurements of Ozone Response to Emissions Perturbations in California

A new technique was used to directly measure O3 response to changes in precursor NOx and VOC concentrations in the atmosphere using three identical Teflon “smog chambers” equipped with UV lights. One chamber served as the baseline measurement for O3 formation, one chamber added NOx, and one chamber added surrogate VOCs (ethylene, m-xylene, n-hexane). Comparing the O3 formation between chambers over a three-hour UV cycle provides a direct measurement of O3 sensitivity to precursor concentrations. Measurements made with this system at Sacramento, California, between April 2020 – December 2020 revealed that the atmospheric chemical regime followed a seasonal cycle. O3 formation was VOC-limited (NOx – rich) during the early spring, transitioned to NOx-limited during the summer due to increased concentrations of ambient VOCs with high O3 formation potential, and then returned to VOC-limited (NOx-rich) during the fall season as the concentrations of ambient VOCs decreased and NOx increased. This seasonal pattern of O3 sensitivity is consistent with the cycle of biogenic emissions in California. The direct chamber O3 sensitivity measurements matched semi-direct measurements of HCHO / NO2 ratios from the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor (Sentinel-5P) satellite. Furthermore, the satellite observations showed that the same seasonal cycle in O3 sensitivity occurred over most of the entire state of California, with only the urban cores of the very large cities remaining VOC-limited across all seasons. Looking at the entire measurement period, days with baseline chamber O3 concentrations above 90 ppb had median O3 sensitivity that was NOx-limited, suggesting that a NOx emissions control strategy would be most effective at reducing these peak O3 concentrations. In contrast, days with O3 concentrations below 80 ppb had median O3 sensitivity that was VOC-limited, suggesting that an emissions control strategy focusing on NOx reduction would increase O3 concentrations. VOC controls on these intermediate days would be difficult, however, if biogenic VOCs account for the majority of the O3 formation. This challenging situation suggests that emissions control programs that focus on NOx reductions will immediately lower peak O3 concentrations, but slightly increase intermediate O3 concentrations until NOx levels fall far enough to re-enter the NOx-limited regime. The spatial pattern of increasing and decreasing O3 concentrations in response to a NOx emissions control strategy should be carefully mapped in order to fully understand the public health implications.

Airborne methane surveys pay for themselves: An economic case study of increased revenue from emissions control

We present an economic analysis of an emissions monitoring and capture program for a mid-sized Permian Basin operator, Triple Crown Resources (“Triple Crown”). Data from this campaign was gathered using repeat airborne surveys provided by Kairos Aerospace (“Kairos”). Key findings include:- The total volume of detected emissions from Triple Crown operations decreased by 70% from the first to the second survey.- Captured gas revenue in the first month was approximately $139,000 and paid for the full cost of the first campaign (including survey, follow-up inspection, and repair) within 5 days.-Analysis of emissions detected from a range of anonymized Permian Basin operators show that a mid-sized operator with a median emissions profile could expect a campaign to pay back in 16.8 days.-Gas samples collected from various points across Triple Crown’s operation showed significant variation in gas value, with tank vapor gas priced as high as $22/MCF.- Kairos survey technology was found to be an effective and highly competitive option for carbon reduction relative to wind, solar, and LED lighting, achieving a cost of $0.54 for every one tonne of CO2e eliminated.