[Characteristics of Ozone over Standard and Its Relationships with Meteorological Conditions in Beijing City in 2014].

The spatial-temporal distribution characteristics of O and the correlations between O and meteorological elements in Beijing urban area were investigated based on the hourly O monitoring data from January to December in 2014 released by Beijing Municipal Environmental Monitoring Center. The annual concentration of O in Beijing was about 56.18 μg·m in 2014. In the over polluted days during May and September, the O concentration could reach as high as 148.05 μg·m. The diurnal distribution of ozone presented a clear unimodal pattern with its peak appearing at 15:00 or 16:00 and trough at 06:00 or 07:00 and the concentrations of O during 09:00 and 23:00 was significantly higher than those in the Summer time. For the spatial distribution of O, the concentration was lower in central urban area with the highest concentration appearing at plant garden site in the west of the urban area. Ground weather type of O over polluted days was divided into three categories including high-pressure, low-pressure, equalizing field, which accounted for 16%, 36%, 48%, respectively. The concentration of O was negatively correlated with the air pressure, humidity and visibility while it was positively correlated with the wind speed and temperature. In one heavy pollution episode of O caused by local photochemical pollution and regional transport from May 29th to June 1st in 2014 in Beijing, regional transport showed a very important influence on the concentration of O in Beijing.