春节期间燃放烟花爆竹对柳州市区PM2.5中水溶性离子的影响

The Impact of Firecrackers to the Water-soluble Ions of the PM2.5 during the Spring Festival in Liuzhou

为了解柳州市春节期间燃放烟花爆竹对PM2.5的污染程度及水溶性离子质量浓度的影响,于2016年1月16~17日、2月7~8日在柳州市环境保护监测站设置采样点,同时采集样品并利用离子在线分析仪Marga分析样品,目的是阐述在监测期内集中且大量地燃放的烟花爆竹对大气中的颗粒物和水溶性离子浓度的影响及其变化特征。结果显示除夕夜PM2.5小时平均质量浓度最高达502μɡ/m3,大气能见度急速下降。水溶性离子的数据表明,燃放烟花爆竹是导致春节期间PM2.5中水溶性离子浓度增加的首要因素。其中NH4+、NO3-、SO42-是PM2.5中主要的水溶性离子,分别约占总离子比重的16.05%、19.64%、49.99%,K+、Na+、Cl-表现出比较高的相关性,说明了烟花爆竹在燃放过程中释放出特征离子成分。此外,运用主成分分析可知春节期间PM2.5中水溶性离子主要来自烟花爆竹的燃放,在燃放烟花爆竹时段大气中的NOx、SO2存在明显的二次转化过程,从而使PM2.5中的物质发生变化,并改变大气中PM2.5的pH值。

To investigate the pollution level and the effect of setting off fireworks and firecrackers on water-soluble ions of the PM2.5 during the spring Festival, sampling points were setat the Environmental Monitoring Station in Liuzhou, on January 16th, 17th and wasset on February 7th, 8th. In order to describe the characteristics of atmospheric particulates and water-soluble ions affected by large quantities of fireworks and firecrackers, samples were collected and analyzed by using Marga Ion On-line Analyzer. The results showed that PM2.5 mass concentration increased to an average of 502 μg/m3 per hour in New Year's Eve, and atmospheric visibility dropped during the firework period. What’s more, the data of water-soluble ions suggested that setting off fireworks and firecrackers was the main source of water-soluble ions of the PM2.5. NH4+ and NO3-, SO42- were the main water-soluble ions of PM2.5, accounted forapproximately16.05 %, 19.64 % and 49.99% of the total ion density respectively, K+, Na+, and Cl- showed relatively high correlation. Moreover, secondary transformation of NOx, SO2 were observed during the firework period by using principal component analysis, which means fireworks can lead to a change of pH of the PM2.5.