Lyu, CongmengCapps, Shannon L.Kurashima, KentHenze, Daven K.Pierce, GordonHakami, AmirZhao, ShunliuResler, JaroslavCarmichael, Gregory R.Sandu, AdrianRussell, Armistead G.Chai, TianfengMilford, Jana2021-05-262021-05-262021-02-011352-2310118113http://hdl.handle.net/10919/103521Recently, oil and natural gas (O&NG) production activities in the Denver-Julesburg Basin have expanded rapidly. Associated nonmethane hydrocarbon (NMHC) emissions contribute to photochemical formation of ground-level ozone and include benzene as well as other hazardous air pollutants. Using positive matrix factorization (PMF) and chemical mass balance (CMB) methods, we estimate how much O&NG activities and other sources contribute to morning NMHC mixing ratios measured from 2013 to mid-2016 at a site in Platteville, CO, in the Denver-Julesburg Basin, and at a contrasting site in downtown Denver. A novel adjoint sensitivity analysis method is then used to estimate corresponding contributions to ozone and ozone-linked mortality in the Denver region. Average 6-9 am NMHC mixing ratios in Platteville were seven times higher than those in Denver in 2013 but four times higher in 2016. CMB estimates that O&NG activities contributed to the Platteville (Denver) site an average of 96% (56%) of NMHC on a carbon basis while PMF indicated 92% (33%). Average vehicle-related contributions of NMHC are estimated as 41% by CMB and 53% by PMF in Denver. Estimates of the fractional contribution to potential ozone and ozone-linked mortality from O&NG activities are smaller while those from vehicles are larger than the NMHC contributions. CMB (PMF) indicate that greater than 78% (40%) of annual average benzene in Denver is attributable to vehicle emissions while greater than 75% (67%) of benzene in Platteville is attributable to O&NG activities.application/pdfenCreative Commons Attribution-NonCommercial-NoDerivs 4.0 InternationalOil and natural gasNonmethane hydrocarbonGround-level ozonePremature mortalitySource apportionmentAdjoint sensitivity analysisArticle - Refereedhttps://doi.org/10.1016/j.atmosenv.2020.1181132461873-2844