The role of organic aerosols (OA) as ice nucleating particles (INPs) deserves attention because of their high atmospheric abundance. The low concentration of INPs poses challenges in identifying the ice nucleation (IN) of OA among a mix of aerosol types in ambient environment. This study coupled a catalytic stripper system (350°C heating) with a continuous flow diffusion chamber to online investigate the immersion INPs of ambient particles at −30°C at a suburban site. Significant reduction (71 ± 25%) of INP concentrations after evaporation suggested that INPs can be significantly contributed by volatile OA. In addition, nonvolatile OA were more efficient INPs than black carbon. Oxygenated OA by photooxidation and lower ambient promoted the IN activity at noon, when the OA may be more viscous. These results hereby present the first field evidence that OA in anthropogenically influenced regions can be efficient INPs well above the homogeneous IN temperature. Plain Language Summary Ice nucleating particles have an important impact on weather and climate by modulating cloud microphysics. Globally, measurements have demonstrated the ubiquitous presence of ice nucleating particles (INPs); however, the contribution of abundant organic aerosols (OA) to INPs remains uncertain owing to their complex compositions and varying phase states. In this study, using concurrent measurements between ambient and heated INPs, we prove the important contribution of volatile OA at 350°C to immersion freezing INPs at −30°C, especially at noon, when OA are more solid‐like because of their oxygenation by photooxidation and lower ambient relative humidity. In addition, nonvolatile OA were found to be a more efficient INPs than black carbon. Therefore, our results provide field evidence that OA in anthropogenically influenced regions could serve as an important atmospheric INPs at 8°C above the homogeneous freezing temperature. Key Points Field measurements prove contribution of organic aerosols (OA) in anthropogenically influence region to immersion mode ice nucleation (IN) OA oxygenated by photooxidation and lower relative humidity showed a correlation with increased at noon Nonvolatile OA at 350°C heating have a higher IN efficiency than that of black carbon