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Hong Kong could get less polluted winter thanks to El Niño, as weather effect brings less mainland Chinese smog

  • More rain and higher wind speeds help disperse pollutants
  • City’s air quality tends to decline during autumn and winter as northerly winds bring mainland pollution

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If conditions are intense enough, Hong Kong may experience relatively cleaner winter air. Photo: Winson Wong

Hong Kong could experience a less polluted winter than normal if a strong enough El Niño weather effect whips up in the Pacific Ocean towards the end of what is typically the smoggiest season of the year, findings from a new study suggest.

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The climate pattern describes the slight warming of sea surface temperatures over the eastern equatorial Pacific Ocean every few years due to the slackening of the trade winds across it. A La Niña effect brings the opposite.

According to Chinese University researchers, Hong Kong’s air quality is usually higher under El Niño conditions as the associated weather – more rain, less frequent northerly winds and higher wind speeds – tend to disperse pollutants.

The opposite was true for La Niña events, in which pollutant concentrations, especially from mainland China, were found to increase substantially.

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