Fig. 2: Time series of a winter nitrate pollution event.
From: Nitrate pollution deterioration in winter driven by surface ozone increase
The figure shows the time series of meteorological parameters and chemical species measured in shanghai on Jan 1–Feb 28, 2019. UTC + 8 denotes Coordinated Universal Time +8 h and represents local solar time in hours. A Surface temperature (TEMP) and relative humidity (RH); B NO2 and VOCs concentrations; C NO and HONO concentrations; D NO3− and HNO3 concentrations; E O3 and PM2.5 concentrations. Here, we define daily average NO3− concentration ≥20 μg m−3 as nitrate pollution (NP) and its <20 μg m−3 as non-nitrate pollution (NNP). The gray area in subfigures A-E is the NP. F The distribution of the above 10 meteorological parameters and chemical species in NNP and NP. The box plot provides the 10th, 25th, 50th, 75th, and 90th percentiles of the source sample data, and the red pentagrams represent the average.
