| The atmospheric pollution events have absorbed more and more social attention.Especially in recent years,It has appeared obvious regional characteristics of atmospheric pollution in Beijing-Tianjin-Hebei region.Through the tethered balloon vertical observation combined with aircraft research techniques,spatial distribution features of gaseous pollutants in the summer of Beijing-Tianjin-Hebei region were studied.According to the characteristics of the diurnal variation of the boundary layer,there were three different time periods to vertically observation of gaseous pollutants(O3,NO,CO and VOCs)in Gaocun,Tianjin Wuqing.With Beijing as the center,aircraft observation were taken in three different region which in the southwestern(lines Ⅰ),southern(lines Ⅱ),eastern(lines Ⅲ)of Beijng.At the same time,some comprehensive observation combined the tethered balloon with the aircraft were organized,and the main conclusions were as follows:(1)Ozone vertical distribution was associated with boundary layer conditions,and there was a clear dividing line in the morning and evening time.But at noon time,the vertical distribution of ozone concentration was the certain fluctuation with the change of height,but was homogeneous as a whole.Ozone vertical distribution in the surface layer was different,showed the characteristics of uniform vertical distribution in the morning.But for evening,ozone concentration in the surface boundary layer increased with increasing of the height.In the early morning hours,ozone concentration on the same height had the little change of the time.Ozone concentration distribution was associated with air mass,and southern air would lead to the increase of ozone concentration.(2)N0 as a primary pollutant,the vertical distribution was under the influence of many factors,in addition to related to boundary layer,also had close relationship with human activity.NO early in the morning and evening also appear obvious stratification,but not appear at the noon.From the point of the overall characteristics of vertical distribution,early in the morning NO showing a downward trend with the increase of height,at noon time distribution was more uniform,however it would have large fluctuations in the evening after sunset.Through correlation analysis found there was little definite correlation between NO and ozone in the vertical direction,but obvious positive correlation to both on the same height through correlation analysis.Air masses of different direction had little effect on the concentration of NO.(3)As a whole,the vertical distribution of CO concentrations was no obvious stratification characteristics.Vertical distribution of CO at noon time was similar with early in the morning and had a relatively uniform vertical distribution;There were two types of the vertical distribution characteristics of CO,the first one was the concentration gradually decreases with the increase of height,and the second was uniformly distributed in the vertical direction.A positive correlation relationship between CO and NO,may suggested that they came from the same source.The correlation between CO and ozone in the vertical direction was relatively complicated,but there was a clear correlation between the same height.(4)In the vertical distribution of VOCs(Volatile organic compounds),the ground concentrations was relatively low,and relatively high value of concentrations were appeared at low altitude 100 m and 300 m.the high concentrations of species at 100 m and 300 m were similar.In the general,the concentration of TVOCs(Total volatile organic compounds)in the evening was lower than in the morning.(5)For the horizontal distribution characteristics of VOCs in Beijing-Tianjin-Hebei region,the highest concentration points at 600 m altitude was Langfang area along the border of Beijing and Tianjin.VOCs pollution was severe at 1200m,and the highest concentration of sample point was also located in Langfang,but including the suburbs of Beijing(northeast)and other(western)on the suburbs of Tianjin and Baoding southern suburbs,and Tangshan were relatively light.In the altitude of 2400m,VOCs pollution was less than that of 1200 m and 600 m,and Baoding was more relatively heavy than Tianjin,Acetone was a higher concentration of VOCs species,whether in the low or high altitude.VOCs and ozone had positive correlation,and the increase of VOCs concentration would lead to higher ozone concentration.(6)For routes Ⅰ,ozone concentration in the morning time was lower than in the afternoon,the higher concentration appeared in the south of Beijing,including Beijing －Baoding direction and Beij ing-Langfang direction.From routes Ⅱ area,ozone concentration distribution was relatively uniform,the concentration were relatively low in the south of Baoding,west of Cangzhou area.For routes Ⅲ,it obviously presented that the O3 concentration in south regions was lower than north regions,lower in east regions than west regions.Ozone pollution of the whole regions were heavier in the part of Langfang which was between Beijing and Tianjin and the northwest regions of Tianjin.(7)NO horizontal distribution had obvious regional characteristics and obvious "big city" effect.High concentration area appeared in this two megacities-Beijing and Tianjin and its surroundings.In Beijing-Langfang-Tianjin regions,concentration of NO was higher than Baoding region,showing a high concentration of north and east regions,but lower in the west and south regions.In addition,it had changes of day and night,directly related to human emissions.In the early morning,NO concentration was relatively uniform,and much lower than during the day.(8)Horizontal distribution of CO was relatively uniform,For routes Ⅰ,and high concentration points was Beijing south-Langfang-Tianjin region.From routes Ⅱ area,,the high concentration region appeared in which was from Tianjin to Baoding.For the area in line Ⅲ,it presented the CO concentration in the eastern and southern regions was higher than in the western and northern regions,and high concentration region area was in Tianjin and Tangshan.CO concentration distribution in high level would be affected by the regional transmission.(9)The synchronous observation by aircraft and tethered balloon found that the high ozone concentration was at an altitude of about 600～1800 m range.It presented the characteristics of the high middle,low both ends in vertically direction.At the same period,ozone concentration at the same height had a larger distinction for different time,and found that may be affected by the southern regional air pollution.For Gaocun observation point,the concentration of NO and CO distribution were relatively uniform and lower on the vertical direction,due to far away from the city. |
