基于无人机观测研究杭州湾化工园区近地面层臭氧垂直廓线

为了解化工园区大气污染情况,使用自主研制的微型大气检测仪结合无人机研究化工园区臭氧(O₃)垂直廓线,在2020年8月~2021年1月于杭州湾上虞经济技术开发区开展了12d无人机外场观测实验.各观测日从08:00~18:00每隔1h进行一次飞行观测,每次观测分别获得了离地面0,50,100,200,300,400,500m的O₃、总挥发性有机物(TVOCs)和二氧化氮(NO₂)浓度.结果表明:受气象因素、地面工厂排放以及早晚出行高峰的影响,TVOCs和NO₂浓度整体随高度增加而下降,其中NO₂浓度随高度上升而下降的幅度较明显,在0m处浓度为19.7~59.1μg/m³,500m处为5.9~21.7μg/m³,下降率为40~70%,TVOCs和NO₂浓度都呈现出早晚高、正午低的日变化趋势,此外可能受逆温层的影响导致个别天数NO₂浓度在400~500m不降反升;O₃受前体物光化学反应、太阳辐射强度及平流层输送的影响,其浓度随高度增加而下降,平均浓度在0m处为49.2μg/m³,500m处为98.4μg/m³,O₃日变化浓度在15:00~17:00达到峰值.TVOCs和O₃、NO₂和O₃在各高度浓度均呈负相关,受不同季节气象因素差异和冬季取暖排放增加的影响,O₃浓度季节变化为夏>秋>冬,TVOCs和NO₂浓度为冬季>秋季>夏季.后向轨迹聚类分析表明化工园区本地O₃浓度会受区域输送影响升高,在冬季时由于气温低不利于前体物生成O₃,本地O₃浓度受区域输送影响较夏季小.

Vertical profiles characteristics of near surface layer ozone in Shangyu Economic Development Zone of Hangzhou Bay based on unmanned aerial vehicle

In order to understand the air pollution in chemical parks, the vertical profiles of ozone (O₃) in chemical park were studied bya self-developed miniature atmospheric detector combined withan unmanned aerial vehicle(UAV), a 12-day UAV field observations was carried out in Shangyu Economic Development Zone of Hangzhou Bay during August 2020 to January 2021. Flight observations were conducted every 1h from 08:00 to 18:00 on each observation day, the concentrations of O₃, TVOCs and NO₂ were obtained at 0, 50, 100, 200, 300, 400 and 500m above the ground for each observation. The results showed that the concentrations of TVOCs and NO₂ usually decreased with increasing height due to meteorological factors, ground-level plant emissions and peak travel, and the concentrations of NO₂ decreased more significantly with increasing height, ranged from 19.7~59.1μg/m³ at 0m to 5.9~21.7μg/m³ at 500m, with a decreased rate of 40%~70%.The concentrations of TVOCs and NO₂ showed a daily trend of high in the morning and evening, low in the noon. In addition, the concentrations of NO₂ increased at 400~500m in some days caused by inversion layer. The concentrations of O₃ increased with height affected by the photochemical reaction of precursors, solar radiation intensity and stratospheric input, the average concentrations were 49.2μg/m³ at 0m and 98.4μg/m³ at 500m, and the peak value of daily variations reached at 15:00~17:00. TVOCs and O₃, NO₂ and O₃ were negatively correlated at all heights. The seasonal change of O₃ concentrations were summer>autumn>winter, and the concentrations of TVOCs and NO₂ were winter>autumn>summer, affected by the difference of meteorological factors in different seasons and the increase of heating emissions in winter. Backward trajectory cluster analysis showed that the local O₃ concentrations in chemical industry park would be affected by regional transport, and the local O₃ concentrations in winter was less influenced by the regional transport than in summer because the low temperature was not conducive to the generation of O₃ from precursors.