| Along with rapid economic development, xi'an urban area near the ground O3 concentration increased significantly in recent years. In June 2013 to May 2014, this article in xi 'an urban area 10 atmospheric observation point on the surface O3 in the atmosphere and its precursor(NOx, CO), particulate matter(PM2.5 and PM10) are analyzed in observation, combined with the meteorological conditions during the observation, the study of spatial and temporal variations of O3 concentration, and the excessive day and not to exceed bid influence factors were analyzed.In June 2013 to May 2014 in downtown xi 'an ozone concentration were analyzed, and found that the main O3 concentrations present for the northeast to southwest on the space distribution trend of gradually increased, the contaminated degree of sorting for the lianhu area > the yanta district > the weitang area > new city area > the baqiao area; On the basis of the primary pollutants and air quality in calculation results found that ozone pollution mainly concentrated in six to nine months of 2013, observation period, the city a total of 45 days, August more overweight situation.Season the concentration change of summer > autumn > spring > winter; Each site of seasonal variation, in addition to the wide pool site performance for spring and summer O3 concentration was flat, and were higher than in autumn; Month change observations for June, July, August, September ozone concentration is higher, November to January at a lower level; Daily variation law completely consistent, each observation site were unimodal type, ozone concentration minimum around 7:00-8:00 in the morning, a peak at about 16:00, hours of daily variation of average concentration range is: 16.35 mu g/m3-92.12 mu g/m3; Weekend and weekday due to the influence of crowd activity rules, overall O3 concentrations slightly higher than the working days at the weekend, but the weekend effect is not obvious.Summer ozone levels by comparison with the standard sample, sample, all the factors, analysis of ozone pollution causes:(1) NO, NO2, and CO concentration level on the standard sample day is significantly higher than the standard sample, affected by meteorological conditions, standard sample sun chemical reaction, ozone concentration is on the high side. NO, NO2, CO, standard sample day hour average concentration variation range of 4.63 to 29.38?g/m3,35.82 to 74.10?g/m3, 0.81 to 1.63 mg/m3.(2) under the stable sunny weather, the sun's ultraviolet radiation intensity and the decrease of the ozone concentration may be mainly caused by aerosol extinction effect.(3) samples of ozone levels, temperature and UV were significantly higher than the standard sample, and in the case of low air pressure and humidity prone to excess ozone, and influenced by the dominant wind direction. Standard samples, the dominant wind direction for north east, and the wind speed during the day slightly higher than the standard sample.For xi 'an meteorological conditions and ozone concentration change to establish the relationship between multiple linear regression equation, the O3 daily maximum 8 hour average concentration and the related meteorological data, regression fitting equation is obtained:Y=-2916.6+8.347X1+0.399X2-2.878X3-0.222X4+2.230X5+0.522X6+5.547X7+0.809X8... |
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