Air pollution from the Ports of Long Beach and Los Angeles: Volatile Organic Compound Emissions

Abstract. Ports are a major source of greenhouse gases and air pollution, impacting downwind, typically disadvantaged communities. The Ports of Los Angeles and Long Beach have dramatically improved criterion air pollutants. However, attention has not been on volatile organic compound (VOC) emissions, gases with notable health concerns (this study). Port-area emissions were studied by an evolving mobile air quality laboratory during 10 surveys from 2019 to 2023 including meteorology, aerosols, 18 trace gases, and targeted air samples for laboratory analysis of up to 87 trace gases. A total of 65 cans were collected for this explorative pilot study. Airborne remote sensing data by the thermal infrared imaging spectrometer, Mako, from 21 surveys conducted between 2015 and 2023, identified 37 distinct trace gases in the port area, including VOCs and chlorinated gases. Normalized (to total aromatic or total VOC) trace-gas profiles and trace-gas ratios revealed distinct patterns between source classes, such as oil production and refineries, and similarities within these classes. For example, the n-butane/iso-butane ratio for Refineries was 0.20, markedly different from other source classes (1.0–2.2), suggesting a different petroleum hydrocarbon source material and maturity.

We demonstrate emissions calculation by fusing discrete air samples with continuous in situ methane data for a methane / VOC plume crossing historically disadvantaged communities in West Long Beach, with annualized emissions of 0.82 Gg methane and 1.2 Gg total VOC (larger than ethane), including a middle school. Satellite CH₄ indicated plume transport was typical. High-density communities of surround the ports.