The emission of pollutants is extremely reduced during the annual Chinese Spring Festival (SF) in Shenzhen, China. During the SF, traffic flow drops by ~&amp;thinsp;50&amp;thinsp;% and the industrial plants are almost entirely shut down in Shenzhen. To characterize the variation in ambient air pollutants due to the <q>Spring Festival effect</q>, various gaseous and particulate pollutants were measured in real time in urban Shenzhen over three consecutive winters (2014&amp;ndash;2016). The

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... s indicate that the concentrations of NOx, volatile organic compounds (VOCs), black carbon (BC), primary organic aerosols, chloride, and nitrate in submicron aerosols decrease by 50&amp;thinsp;%&amp;ndash;80&amp;thinsp;% during the SF period relative to the non-Spring Festival periods, regardless of meteorological conditions, which suggests that these pollutants are mostly emitted or secondarily formed from urban local emissions. The concentration decreasing of regional pollutants or species emitted from natural sources, however, is found to be much less, especially for bulk PM_2.5 (&amp;minus;24&amp;thinsp;%) and O₃ (6&amp;thinsp;%). More detailed analysis of the Spring Festival effect reveals an urgent need to reduce emissions of SO₂ and VOCs on a regional scale rather than on an urban scale to reduce urban PM_2.5 in Shenzhen, which can also produce some use for reference for other megacities in China.