Observations of VOC emissions and photo chemical products over US oil- and gas-producing regions using high-resolution H<sub>3</sub>O<sup>+</sup> CIMS (PTR-ToF-MS)
Journal Article
Abstract. VOCs related to oil and gas extraction operations in the United States were measured by H3O+ chemical ionization time-of-flight mass spectrometry (H3O+ ToF-CIMS / PTR-ToF-MS) from aircraft during the SONGNEX campaign in March–April 2015. This work presents an overview of major VOC species measured in nine oil and gas producing regions, and a more detailed analysis of H3O+ ToF-CIMS measurements in the Permian Basin within Texas and New Mexico. Mass spectra are dominated by small photochemically produced oxygenates, and compounds typically found in crude oil: aromatics, cyclic alkanes, and alkanes. Mixing ratios of aromatics were frequently as high as those measured downwind of large urban areas. In the Permian, the H3O+ ToF-CIMS measured a number of underexplored or previously unreported species, including aromatic and cycloalkane oxidation products, nitrogen heterocycles including pyrrole (C4H5N) and pyrroline (C4H7N), H2S, and a diamondoid (adamantane) or unusual monoterpene. We additionally assess the specificity of a number of ion masses resulting from H3O+ ion chemistry previously reported in the literature, including several new or alternate interpretations.;
