摘要
摘要:为了研究烟花爆竹燃放对空气质量的影响，利用动态滤膜校准系统-微量震荡天平法颗粒物分析仪、大气细颗粒化学组分在线离子色谱监测仪、有机碳（OC）/元素碳（EC）在线分析仪、气态污染物分析仪、常规自动气象站并结合云高仪和微波辐射计等设备于2015年2月18日至3月7日对天津市细颗粒物（PM2.5）及其主要化学组分，气态污染物（SO₂、NO₂、CO和O₃）和气象参数进行连续观测。本文选取3个污染事件作为研究重点进行分析，研究发现：烟花爆竹禁放和限放政策导致除夕夜烟花爆竹燃放量减少，PM2.5峰值与2014年相比明显下降；烟花爆竹禁放和限放区的设立导致天津市PM2.5质量浓度在烟花爆竹密集燃放期间存在明显的空间差异；站点之间小时平均值差异最高达到394 μg/m³。受烟花爆竹燃放的影响，距地面80 m以下颗粒物后向散射强度相近，表明80 m以下颗粒物呈均匀分布。污染事件1是由于烟花爆竹密集燃放引起的，PM2.5主要化学组分为K⁺、SO₄^2-和Cl^-，同时SO₂和CO质量浓度显著升高；但EC和OC质量浓度并未明显增加。污染事件2的形成是由于不利的气象条件（逆温、逆湿、下沉气流和较高的相对湿度）促进了SO₂和NO_x在烟花爆竹排放的颗粒物表面发生非均相化学反应，导致SO₄^2-和NO₃^-浓度快速增加。污染事件3由元宵节烟花爆竹燃放引发，而后呈现二次无机组分与臭氧协同增长的复合型污染特征；此外区域传输对污染事件3也有重要贡献。
关键词:天津/
细颗粒物(PM2.5)/
硫酸盐/
硝酸盐/
有机碳/
元素碳/
烟花爆竹
Abstract:To study the impact of firework discharge on air quality in Tianjin, fine particulate matter (PM2.5, aerodynamic diameter is less than or equal to 2.5 microns particulate matter) and its major chemical compositions as well as meteorological variables were measured in Tianjin from 18 Feb to 7 Mar using various instruments like the Tapered Element Oscillating Microbalance PM2.5 instruments with Filter Dynamic Measurement System, an online Rapid Collector of Fine Particles and Ion Chromatography system, an online OC/EC analyzer, a ceilometer and a microwave radiometer and so on. In this study, three air pollution episodes are selected for analysis. The results show that the implementation of policies of prohibition and restriction on firework discharge resulted in a decline in firework discharge volume and the hourly maximum value of PM2.5 concentration on the Chinese New Year's Eve of 2015 was lower than that in 2014; the set-up of areas of prohibitions and restrictions on firework discharge led to obvious spatial differences in PM2.5 concentration in Tianjin with the maximum difference of 394 μg/m³. The attenuated backscatter densities were similar everywhere from the surface to 80-m height due to the impact of fireworks discharge, suggesting identical vertical distribution of PM2.5 below 80 m. This result is consistent with previous measurements. Air pollution episode 1 (EP 1) was caused by dense discharge of fireworks, in which the main chemical species in PM2.5 are K⁺, SO₄^2-, and Cl^-. Air pollutants like SO₂ and CO evidently increased during this episode. The formation of air pollution episode 2 (EP 2) was attributed to unfavorable meteorological conditions including temperature inversion, wetness inversion, convergence and high relative humidity, which promoted the secondary transformation of SO₄^2- and NO₃^- on the surfaces of particles from firework discharge via heterogenous reactions during EP 2. The third air pollution episode (EP 3) was initiated by the widespread discharge of fireworks on the Lantern Festival and characterized by complex pollution. Collaborative growth of the secondary inorganic components and the O₃ concentration were found during this episode. In addition, regional transport also played an important role in EP 3.
Key words:Tianjin/
PM2.5/
Sulfate/
Nitrate/
Organic carbon/
Elemental carbon/
Firework discharge



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