corded a peak PM10 concentration exceeding 600 micrograms per cubic meter, with visibility reduced to just 3 to 4 kilometers, per CCTV. Dust storms are generally perceived to occur in Northwest C
, meteorological monitoring data showed. Various types of dust events peaked in the 1950s at an average of 63 per year, hitting a high of 89 in 1954, before falling to 5.7 events per year in the 1990s
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