基于高频空间分析的襄阳市春节期间烟花爆竹禁放效果评估

为研究襄阳市区春节期间空气污染时空规律及烟花爆竹禁放效果，利用密集空气质量监测微型站、稀疏国控站以及气象站等数据，借助高频率空间分析、相关性分析以及浓度特征比较等方法，研究了局地尺度下襄阳市区春节期间空气污染时空变化，评估了历年春节期间烟花爆竹禁止燃放举措的实施成效。结果表明：1）2018年新春佳节期间襄阳市区天气总体平稳，空气质量整体较差，受市区外围周边地区在除夕至初一燃放烟花爆竹影响，空气质量由除夕轻度转成初一重度污染；从除夕夜T 19:00开始，PM_2.5和PM₁₀质量浓度逐步上升，初一T 00:00过后直线升高，至初一早上T 08:00达到春节期间峰值，该时段SO₂和NO₂质量浓度也有明显升高。2）新春佳节期间局地尺度下襄阳市区PM_2.5和PM₁₀日均质量浓度空间分布整体较为一致，在除夕、初二至初五均呈现以汉江与唐白河为界、“南高北低”的中度以上污染态势，而初一、初六则呈现污染连绵成片、大范围覆盖等特点。3）市区外围周边地区烟花爆竹燃放是造成春节期间襄阳市区除夕夜至大年初一空气污染突变严峻并持续至初四的主要原因；交通尾气、道路扬尘、居住商业餐厨油烟等也是春节期间襄阳市区空气污染的重要源头；独特地理环境是襄阳频繁遭受空气污染的基底因素。4）近些年襄阳市区空气污染整体有所改善，这与持续采取大气污染防治举措密切相关；各年份空气污染均具有明显“春节效应”，受烟花爆竹燃放影响一般会持续3 d轻度以上污染，初四逐渐转为本地污染排放影响主导；因此，适度扩大禁鞭区域，加强精准防控监管，可有效改善春节期间襄阳市区整体空气质量。文章揭示了通过高密度站点监测网络结合高时间分辨率空间分析进行污染物空间格局刻画，可用于局地尺度空气污染时空变化的精准识别和过程推导，并为特殊时期和污染天气下大气污染防控治理提供更可靠的参考依据。

Evaluation of the Effect of Firework and Firecracker Prohibition during the Spring Festival in Xiangyang on a Local Scale

Based on air quality data from dense local micro-stations and sparse national stations, and meteorological data, this study examined the temporal and spatial patterns of air pollution during the Spring Festival in Xiangyang using high-frequency spatial analysis, correlation analysis, and pollutant concentration comparison. The implementation effect of a policy banning fireworks and firecrackers during the Spring Festival was evaluated. The results showed that during the Spring Festival in 2018, the weather in Xiangyang was relatively stable, and the air quality was generally poor. Owing to the influence of fireworks and firecrackers set off from New Year's Eve to the first day of the Lunar New Year in the peripheral areas of Xiangyang, the air pollution condition shifted from mild to severe. The concentrations of PM_2.5 and PM₁₀ increased gradually from 19:00 on New Year's Eve, rose linearly after 00:00 on the first day of the Lunar New Year, and then reached a peak during the Spring Festival at 08:00. During this period, the concentrations of SO₂ and NO₂ also increased significantly, whereas that of CO had no obvious regularity. During the Spring Festival, the spatial distribution patterns of PM_2.5 and PM₁₀ daily average concentrations showed a moderate or higher pollution trend of "high in the South and low in the North" on New Year's Eve and the second to fifth days of the Lunar New Year, with Hanjiang and Tangbai Rivers as the boundaries. On the first and sixth days of the Lunar New Year, air pollutants covered almost all of Xiangyang. The setting off of fireworks and firecrackers in the surrounding areas is the primary cause of the heavily polluted weather from New Year's Eve to the first day of the Lunar New Year, and until the fourth day. Traffic exhaust, road dust, and cooking fumes remain significant sources of air pollutants in Xiangyang during the Spring Festival. The characteristic geographical environment and variable meteorological elements are important factors that cause air pollution. Owing to the continuous adoption of air pollution prevention and control policies over the past four years, the overall air pollution situation has improved in Xiangyang. The scope of the firework bans was gradually expanded, thus effectively improving the overall air quality. Compared with research on urban air pollution using a small number of monitoring stations, the application of a high-density air quality monitoring network can describe in detail the spatio-temporal distribution characteristics of urban air pollution on a local scale. Accordingly, increasing the frequency of the spatial analysis of air pollution can allow for the deduction of the specific evolutionary process of air pollution in space. Particularly in special periods or polluted weather, a precise understanding of the spatio-temporal evolution of air pollution can provide an important basis and reference for the prevention and control of urban air pollution.