Vertical profiles of aerosol, NO2, H2O and HONO in Hefei and its surrounding agricultural fields

Average aerosol vertical profiles exhibited a Gaussian shape above 100 m with maximum values of 0.67 km-1 and 0.55 km-1 at 300-400 m layer at AHU and CF, respectively. The distinct layered structure mainly attributed to regional transport. Average H2O and NO2 vertical profiles all showed a Gaussian shape and an exponential shape at AHU and CF, respectively. Moreover, the diurnal evolution of H2O profiles performed one peak and bi-peak patterns at AHU and CF, respectively, whereas NO2 at two stations all exhibited bi-peak patterns attributed to vehicle emissions. Average HONO vertical profiles showed an exponential shape and a Gaussian shape at AHU and CF, respectively. Higher HONO (> 0.05 ppb) above 1.0 km at 14:00-16:00 was observed at CF.

在100米以上高度，AHU与CF站点的气溶胶垂直廓线均呈高斯分布，其峰值分别出现在300~400米层段，对应数值为0.67 km⁻¹与0.55 km⁻¹。该显著分层结构主要由区域输送所致。AHU站点的平均水汽（H₂O）与二氧化氮（NO₂）垂直廓线分别呈高斯分布与指数分布，CF站点则分别呈指数分布与高斯分布。此外，AHU与CF站点的水汽廓线日变化特征分别呈现单峰与双峰模式；而两个站点的二氧化氮廓线均呈现双峰模式，其成因与机动车排放相关。AHU与CF站点的平均亚硝酸（HONO）垂直廓线，分别呈指数分布与高斯分布。在CF站点，14:00~16:00时段的1.0千米以上高度，观测到浓度高于0.05 ppb的亚硝酸。