Purpose: To assess household air pollution levels in urban Chicago households and examine how socioeconomic factors influence these levels. Methods: We deployed wireless air monitoring devices to 244 households in a diverse population in Chicago to continuously record household fine particulate matter (PM_2.5) concentration. We calculated hourly average PM_2.5 concentration in a 24-hour cycle. Four factors—race, household income, area deprivation, and exposure to smoking—were considered in this study. Results: A total of 93085 h of exposure data were recorded. The average household PM_2.5 concentration was 43.8 μg m⁻³. We observed a significant difference in the average household PM2.5 concentrations between Black/African American and non-Black/African American households (46.3 versus 31.6 μg m⁻³), between high-income and low-income households (18.2 versus 52.5 μg m⁻³), and between smoking and non-smoking households (69.7 versus 29.0 μg m⁻³). However, no significant difference was observed between households in less and more deprived areas (43.7 versus 43.0 μg m⁻³). Implications: Household air pollution levels in Chicago households are much higher than the recommended level, challenging the hypothesis that household air quality is adequate for populations in high income nations. Our results indicate that it is the personal characteristics of participants, rather than the macro environments, that lead to observed differences in household air pollution.