L. 4-5 p.9995: To be precise, in [Deshler et al., 2003, cited in the paper], the authors mention the value of 150 nm as smallest particle size measured by optical particle counters (OPC) at Laramie. However, these authors also measure condensation nuclei (radius ≤ 0.01 μm) by growing particle with sizes down to 0.01 μm in the sample stream. L. 5-6 p.9995: “sensitive to nature of the particl...