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We use air pollution exposure measurements and household survey data from four studies conducted across three countries in sub‐Saharan Africa (SSA) to analyze the association between carbon monoxide (CO) exposure from cooking with biomass and indicators of cognitive impairment. While there is strong evidence on the relationship between ambient air pollution exposure and cognitive impairment from studies in high‐income countries, relatively little research has focused on household air pollution (HAP) in low‐income country settings where risks of HAP exposure are high. This study is the first to our knowledge to focus on the association between HAP exposure (specifically CO exposure) and cognitive impairment across diverse settings in SSA. We use 24‐hour measurements of primary cooks’ exposure to CO across four study sites: urban Zambia (n= 493); urban Malawi (n= 130); rural Malawi (n= 102); and urban Rwanda (n= 2,576). We model the estimated percent carboxyhemoglobin (%COHb) of cooks and map values to a toxicological profile for risk of cognitive impairment. We find that across all study settings, cooks’ average %COHb levels are below levels of daily concern, but that cooks who use charcoal for preparing greater than 40% of meals are more likely to spend additional time at higher levels of risk. For the urban Zambia sample, we compare %COHb and frequency of charcoal use to a series of cognitive test scores and find no consistent relationships between %COHb and cognitive test scores. High levels of daily CO exposure from cooks across SSA highlight the potential for longer‐term negative cognitive (and other) health outcomes motivating additional research and efforts to characterize and mitigate risk. 

Abstract Existing star-forming vs. active galactic nucleus (AGN) classification schemes using optical emission-line diagnostics mostly fail for low-metallicity and/or highly star-forming galaxies, missing AGN in typicalz∼ 0 dwarfs. To recover AGN in dwarfs with strong emission lines (SELs), we present a classification scheme optimizing the use of existing optical diagnostics. We use Sloan Digital Sky Survey emission-line catalogs overlapping the volume- and mass-limited REsolved Spectroscopy Of a Local VolumE (RESOLVE) and Environmental COntex (ECO) surveys to determine the AGN percentage in SEL dwarfs. Our photoionization grids show that the [Oiii]/Hβversus [Sii]/Hαdiagram (Siiplot) and [Oiii]/Hβversus [Oi]/Hαdiagram (Oiplot) are less metallicity sensitive and more successful in identifying dwarf AGN than the popular [Oiii]/Hβversus [Nii]/Hαdiagnostic (Niiplot or “BPT diagram”). We identify a new category of “star-forming AGN” (SF-AGN) classified as star-forming by the Niiplot but as AGN by the Siiand/or Oiplots. Including SF-AGN, we find thez∼ 0 AGN percentage in dwarfs with SELs to be ∼3%–16%, far exceeding most previous optical estimates (∼1%). The large range in our dwarf AGN percentage reflects differences in spectral fitting methodologies between catalogs. The highly complete nature of RESOLVE and ECO allows us to normalize strong emission-line galaxy statistics to the full galaxy population, reducing the dwarf AGN percentage to ∼0.6%–3.0%. The newly identified SF-AGN are mostly gas-rich dwarfs with halo mass <10^11.5M_⊙, where highly efficient cosmic gas accretion is expected. Almost all SF-AGN also have low metallicities (Z≲ 0.4Z_⊙), demonstrating the advantage of our method.