The relationship between new digital manufacturing technologies (also known as Industry 4.0) and environmental performance has become a subject of interest for both academia and policymakers. An analysis of the impact of robot usage on air environment mediated by energy consumption and moderated by population density is developed and tested using a longitudinal dataset from 74 countries and regions worldwide during 1993–2019. We find the use of robots exacerbates air pollution and climate warming because enhanced productivity and energy efficiency in light of robot usage offer an incentive to expand production and consumption, and thus increase total energy consumption that finally leads to air deterioration. By decomposing the total effect into the direct and the indirect effect, we find that, though industrial robots weakly contribute to reduction in greenhouse gas emission, the indirect adverse impact dominates the direct benefit. In addition, the nexus between robot usage and air environment is conditional on population density which, at large, mitigates the direct effect while amplifies the indirect effect of the adoption of robots on air environment. This study emphasizes the importance of energy consumption and population density in understanding the mechanisms underlying the relationship between robot usage and air environment, which provides both theoretical and practical implications for the balance of industrial intelligentization and ecological environment.