As a meteorological factor, air pollution has emerged as a significant marketing strategy and has garnered extensive attention from the academic community. Contrary to the prevailing lay theory, which posits an increase in online purchases due to air pollution, this study illustrates a counterintuitive result that air pollution can serve as a negative marketing cue affecting consumers’ online purchasing behaviors. Grounded in cognitive load theory, we conducted secondary data analysis and three experimental studies to scrutinize the association between air pollution and online purchases of products unrelated to air pollution. Our findings establish that air pollution can adversely influence online purchasing behavior through the sequential mediation of cognitive state and emotion. Furthermore, this adverse effect can be mitigated with products with a colorful (vs. black-and-white) scheme or associated with a foreign (vs. domestic) brand. Our research not only addresses air pollution as a negative marketing cue in the context of purchasing air pollution-unrelated products online but also clarifies these counterintuitive findings through a serial psychological process. Moreover, this research expands our understanding of the magic effect of specific intrinsic (i.e., product color) and extrinsic (i.e., country-of-origin) product attributes. Accordingly, this research offers insights into marketing strategies that encompass a broader spectrum of products (i.e., air pollution-unrelated products) during periods of air pollution, thereby contributing to online retailing performance.