arising from: Kong et al. Nature Geoscience (2023) https://doi.org/10.1038/s41561-023-01200-8 (2023)

Localized tropospheric nitrogen oxides (NO_x = NO + NO₂) are mostly formed from emission sources, such as large cities¹, mineral mining sites², busy transportation routes³, fuel delivery infrastructure⁴ and wildfires⁵. Kong et al.⁶ recently reported anomalous tropospheric NO₂ columns from spaceborne remote sensing observations of the TROPOspheric Monitoring Instrument (TROPOMI) over Tibetan Plateau lakes and attributed them to megacity-scale emissions from these lakes. Here we report serious anomalies in the NO₂ retrievals over most of these lakes, possibly due to absorption in the water, which may have biased the NO₂ retrieval results. Without addressing this potential absorption, it is premature to attribute any anomalies in tropospheric NO₂ to emissions from Tibetan lakes, let alone estimate their magnitude.