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Previous studies suggest a potentially large burden of respiratory disease attributable to ambient air pollution exposure. Increasingly high air pollution levels in low- and middle-income countries (LMICs) may be contributing to worsening respiratory health. In the course of a 5-year longitudinal study, the influence of annual average ambient nitrogen dioxide (NO₂) at the home location on lung function decline was investigated in a 485-person cohort of low-income adults in Mysore, Karnataka, India. Health data were gathered in two rounds of qualitative questionnaires (2012-2014 and 2017-2018) using standardized interviews, as well as in-home lung function measurements using field spirometers. We estimated annual average ambient NO2 in 2017 at the home location from spatial interpolation of seasonal air pollution sampling. Linear mixed effects models with a person-specific random effect were used to estimate NO₂ versus lung function cross-sectionally at baseline as well as longitudinally over time, with models adjusted for potential confounders including age at baseline, sex, smoking status, and month of data collection to control for potential seasonality. Results indicated cross-sectional associations between NO₂ and lung function post-bronchodilation, with a reduction of -28.2 mL (95% CI: -51.2, -5.28) for FEV1 and -34.3 mL (95% CI: -61.2, -7.47) for FVC post-bronchodilation per 10 ppb increase in NO2. We show limited evidence of longitudinal impacts of air pollution on lung function. Future studies would benefit from time-varying air pollution exposure estimates, as well as subsequent rounds of lung function data collection to assess for longer-term trends in lung function decline.