长株潭城市群PM2．5污染的春节假日效应

摘要

PM2.5 has been a major concern of the public due to its obvious effect of reducing visibility and endangering hu⁃man health. Based on the hourly PM2.5 monitoring data gathered around the clock at 24 monitoring sites in the Chang⁃Zhu⁃Tan metropolitan area, analysis was performed of variation of PM2.5 pollution throughout 7 days before spring festival, 7 days of spring festival and 7 days after the festival in 2013, 2014 and 2015 to explore impacts of holiday activities, inclu⁃ding tourism, on air quality. After excluding the effect of meteorological factors (e.g. daily precipitation> 4 mm), holiday impacts were analyzed from the following three aspects, namely, difference in PM2.5 pollution level, difference in daily var⁃iation of PM2.5 concentrations, and spatial variation of the holiday effect. Results show that PM2.5 concentration was 12μg·m-3 higher during the holiday period than during the days before and after the holiday, as a whole in the metropolitan area, and 41�5% lower during the 7 days after the holiday than during the holiday period, revealing an obvious"post⁃holi⁃day effect". Strongly affected by holiday activities, like setting off fire⁃cracks and fireworks, PM2.5 concentration soared dramatically during the early hours from 00:00 to 02:00 each day of the holiday period, peaking at 02:00 and being 47�6% higher than that during the non⁃holiday periods. The holiday effect varied spatially across the study area. In Chang⁃sha, being the destination of tourists during the holiday period, PM2.5 concentration was 33.5% higher during the Spring Festival than during the non⁃holiday periods, demonstrating apparent impacts of travelling and tourism activities on air quality.%利用长株潭城市群24个监测点PM2．5小时监测数据，研究2013—2015年春节期间（7 d）和春节前后（14 d） PM2．5污染差异及变化，并分析旅游休假活动对空气质量的影响。在去除气象条件（日降水量大于4 mm）影响后，从PM2．5污染程度差异、PM2．5浓度日变化差异和假日效应的空间差异3个方面分析了PM2．5污染的春节假日效应。结果表明，整体上长株潭地区春节期间PM2．5浓度比春节前后高12μg·m－3，但春节后（7 d）PM2．5浓度比春节期间低41�5％，“节后效应”明显。由于受烟花燃放等假日活动影响，春节期间PM2．5浓度在00：00—02：00时段显著上升，02：00时PM2．5浓度比非春节期间高47�6％。在假日效应的空间差异方面，长沙作为游客流入地，春节期间PM2．5浓度比非春节期间高33．5％，体现了人流出行和旅游活动对空气质量的显著影响。