Air Quality
Managing Air Emissions
We are committed to managing air emissions with required programs and advanced systems that go beyond regulations.
Leveraging Technologies to Reduce Emissions
In addition to the comprehensive air monitoring programs already deployed at our refineries to comply with regulatory and permit obligations, we have incorporated supplementary advanced monitoring systems to identify opportunities to reduce air emissions. Ambient air measurements allow refineries to monitor the surrounding communities and posture our team for quick response and mitigative actions even on small emissions sources. We have the following air monitoring programs:
- GMAP Vans Equipped with Duvas DV3000 Instruments, provide real-time mobile air monitoring and quality screenings. The vehicle-mounted UV-DOAS uses ultraviolet spectroscopy and meteorological measurements to identify and quantify gases, such as benzene, SO2, and NOx, at low part-per-billion levels. With an analyzer response time as short as one second, the UV-DOAS combines measurements with geographic mapping of gas concentrations, which enables rapid detection and source identification.
- ATLAS Emissions Management platform was implemented in 2024 to streamline emissions calculations and reporting, support permit compliance tracking, drive consistency across Valero’s facilities, and facilitate company-wide benchmarking and air emissions performance initiatives. Additionally, accounting-style data quality controls have been built into the platform to ensure information integrity for the reporting of GHG emissions.
- Continuous Emissions Monitoring Systems (CEMS) are placed in the outlet stacks of certain fired equipment (boilers and heaters) as well as in process vents of units such as the Fluid Catalytic Cracking Unit (FCCU). CEMS continuously measure the concentration of compounds, such as NOx and SO2, exiting the stack to confirm operations are within permitted limits.
- Continuous Flare Monitoring Systems are installed on flares to measure the amount of process gases routed to the flare for destruction and track operational parameters to confirm the flare is operating properly.
- Stack Testing is conducted periodically on equipment to confirm it is operating properly and within permitted limits.
- Leak Detection and Repair (LDAR) programs ensure our operating sites comply with the EPA's air quality regulations for reducing fugitive emissions. Inspections are conducted on a routine basis. Leaks identified are fixed and re-monitored to confirm repairs are effective. In 2023, we implemented an enhanced LDAR program using optical gas imaging (OGI), resulting in improved leak identification, greater worker safety and cost savings. Following the success of the program, we are considering adopting optical gas imaging-enhanced LDAR at additional refineries.
- Routine Optical Gas Imaging (OGI) Inspections of storage tanks, wastewater treatment operations and other equipment are performed using OGI cameras equipped with infrared technology capable of detecting VOC leaks that are not visible to the naked eye.
- Unit Battery Limits Monitors placed around the perimeter of refinery process units continuously measure for target compounds. These stationary air monitors serve as an early warning system if elevated concentrations are detected.
- Personal Gas Monitors are being used throughout all Valero refineries. Employees and contractors are required to wear these monitors while in and around process units. The monitors sound an alarm and record the event when elevated levels of gases are detected.
- Upgraded Personal Four-Gas Monitors are being rolled out to continuously measure O2, CO, H2S and lower explosive limit.
- Fenceline Benzene Monitors are located around most of our refineries to collect passive samples at designated intervals. Additionally, environmental Gas Chromatographs (eGCs), stationary analyzers that detect gases such as benzene in ambient air, are deployed at certain sites in areas at or inside the fenceline to allow for rapid detection.
*Beginning in 2022, fresh water withdrawn includes volume that was withdrawn and sold. Values in prior years include only freshwater used in Valero's operations.