Do More Frequent Temperature Inversions Aggravate Haze Pollution in China?

By using twice daily high-resolution radiosonde observations, here we assessed spatiotemporal variability of temperature inversion (TI) and its impact on PM2.5 pollution levels in China from 2014 to 2020. It was found that both surface-based inversion (SBI) and elevated inversion (EI) became increasingly frequent across China, at a rate of 1.42% a(-1) (1.15% a(-1)) and 2.82% a(-1) (3.23% a(-1)) at 0800 (2000) Beijing time (BJT), respectively. However, the intensity of SBI and EI at 0800 (2000) BJT decreased at -0.17 (-0.43) and -0.07 (-0.05) degrees C 100m(-1) decade(-1), making annual mean PM2.5 increment induced by TI dip by 52.5% (73.2%) for the whole study period. Still positive TI induced PM2.5 increments demonstrate an offsetting effect between TI and emission control on haze pollution, underscoring the importance of fully considering TI contribution when assessing the emission control effect on haze reduction.