Climate justice and California’s methane super-emitters: An environmental equity assessment of community proximity and exposure intensity

Abstract

BACKGROUND AND AIM: Issues of environmental justice exist with respect to toxic waste facilities, concentrated animal feeding operations, and air pollution exposure. For the first time, we aimed to characterize potential disparities in exposure to methane super-emitters in California with respect to race/ethnicity, socioeconomic status, and civic engagement. METHODS: We obtained location, category (e.g., landfill, refinery), and emissions rate of California methane super-emitters from Next Generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) flights conducted between 2016–2018. We identified block groups within 2km of super-emitters (exposed) and 5-10km away (unexposed) using dasymetric mapping and assigned level of exposure among block groups within 2km (measured via number of super-emitter categories and total methane emissions). We used generalized additive mixed models with a logit-link to assess the association between block group-level sociodemographic variables and odds of exposure to a super-emitter or, among exposed block groups (those within 2km of a super-emitter), odds of higher intensity exposure to multiple categories of super-emitters. Mixed models included a random intercept for county. We allowed for deviations from linearity using penalized splines. RESULTS:Analyses included 483 super-emitters. The majority were dairy/manure (n = 213) and oil/gas production sites (n = 127). Results from fully adjusted logistic mixed models were consistent with environmental injustice in methane super-emitter locations. For example, for every 10% increase in non-Hispanic Black residents, the odds of exposure increased by 10% (95% CI: 1.04, 1.17). We observed similar disparities for Hispanics and Native Americans, but not with indicators of socioeconomic status. Among block groups located within 2km, increasing proportions of non-White populations and lower voter turnout were associated with higher super-emitter emission intensity. CONCLUSIONS:Previously unrecognized racial/ethnic disparities exist in exposure to California methane super-emitters, which future policies should address. KEYWORDS: Environmental justice, Air pollution, Socio-economic factors (non-chemical stressors), Environmental disparities