Study On The Relationship Between Air Pollution And Meteorological Conditions In Represent Cities Of Different Climatic Regions And Their Forecast

Air pollution not only affects people’s lives and health,but also has a great impact on the sustainable development of the entire social economy,therefore,research on air pollution and its forecast is very important.Based on this,the article uses day by day and hour by hour data on concentrations of PM_2.5,PM₁₀,SO₂,NO₂,O₃ and CO from 10 representative cities in different climatic regions of the country（Harbin,Urumqi,Lanzhou,Taiyuan,Beijing,Lhasa,Chengdu,Wuhan,Nanjing and Guangzhou）from2015 to 2017,the characteristics of the time variation of pollutants in 10 representative cities and the correlation between pollutants were studied,and using the same period of NCEP/NCAR GFS numerical forecast products（potential height,wind speed u,v component,vertical speed,air temperature and relative humidity,ground dew point temperature,boundary layer thickness and boundary layer ventilation coefficient and other air pollution meteorological parameters）,measured air pollution meteorological parameters（stable energy,fake equivalent temperature difference,near ground surface isobaric height field gradient,lower average wind speed,vorticity,divergence,temperature advection）in the temperate and subtropical cities（take Beijing and Guangzhou as the representative cities）.On this basis,the relationship between air pollutant concentrations and meteorological conditions in Beijing and Guangzhou was studied,a stepwise regression method was used to establish the prediction equations for the air pollutant concentrations(PM_2.5,SO₂,and O₃)in the two cities and the prediction results were tested.The main findings are as follows:（1）The annual changes of PM_2.5,PM₁₀,SO₂,NO₂ and CO concentrations in 10 representative cities are basically characterized by“high in winter and low in summer”,while the annual variation trend of pollutant O₃ concentration is opposite.The annual variation of the pollutant concentrations in the northern representative city is greater than that in the southern representative city.The six kinds of pollutants all have obvious diurnal variations,the O₃ concentration reached the highest between 14:00 to 16:00 and the lowest concentration at night,the other five pollutant concentrations peaked mostly in the morning and at night,and the valley values basically appeared around 16:00.In addition SO₂ and O₃ in the representative cities of the North,the diurnal variations of the other four kinds of pollutants are two peaks and two valleys.In the representative cities of the South,with the exception of PM_2.5,SO₂ and O₃,the diurnal variations of other three pollutant concentrations are both two peaks and two valleys.Positive correlations among the five pollutants of PM_2.5,PM₁₀,SO₂,NO₂ and CO in all representative cities,in addition to other representative cities outside Guangzhou,O₃ is negatively correlated with other pollutants,Guangzhou PM_2.5,PM₁₀0 and O₃ are positively correlated,SO₂,NO₂ and CO are negatively correlated with O₃.The positive correlation between PM_2.5.5 and PM₁₀0 is the highest,and the negative correlation between O₃ and NO₂ is the highest.（2）The study on the synergistic effect of temperature annual range and latitude on annual range of six pollutant concentrations from 2015 to 2017 concludes that:Under the synergistic effect of temperature annual range and latitude,high latitude is the leading factor which leads to the increase of PM_2.5.5 and PM₁₀concentrations annual range,and the increase of temperature annual range further strengthens the effect of latitude on the concentration annual range.The relationship between SO₂ concentration annual range and temperature annual range is not obvious,but it reaches the peak value of annual range at 39°N,when the latitude is 22°N,32°N and 42°N,the NO₂ concentration annual range is basically always in a larger state,and at the latitude corresponding to the peak,the NO₂ concentration annual range increases further with the increase of temperature annual range.When the temperature annual range is around 5℃,the O₃concentration annual range is the smallest,and the high latitude temperature annual range is around 23℃,the O₃ concentration annual range is the largest.The influence of high latitude temperature annual range on CO concentration annual range has a synergistic strengthening effect.（3）The correlation between meteorological parameters related to air pollution,which are rarely used in the past but can better represent the atmospheric diffusion characteristics of the boundary layer,and the concentrations of three pollutants(PM_2.5,SO₂,and O₃)in Beijing and Guangzhou,are optimized and statistically analyzed.Studies have shown that the correlations between stable energy,false equivalent temperature differences,vorticity,temperature advection,and the concentrations of PM_2.5.5 and SO₂ in Beijing and Guangzhou are almost the opposite.The negative correlation between stable energy,vorticity and O₃ in the two cities is dominant,the correlation between fake equivalent temperature difference and O₃in Beijing and Guangzhou are respectively negatively correlated and positively correlated,the temperature advection is just the opposite.The correlation between temperature advection and the concentration of three pollutants is lower than other meteorological conditions,and there is no obvious distribution rule.（4）The negative correlation between the gradient of height field,average wind speed at low level and the concentrations of PM_2.5.5 and SO₂ in Guangzhou was higher than that in Beijing.There was a positive correlation between the gradient of height field and the concentration of O₃ in the two cities,and a positive correlation and a negative correlation between the average wind speed in the lower level and the concentration of O₃ in Beijing and Guangzhou,respectively.The positive correlation between divergence and the concentrations of PM_2.5,SO₂ and O₃ in Beijing was higher than that in Guangzhou.The thickness of boundary layer was negatively correlated with the concentrations of PM_2.5.5 and SO₂ in two cities and positively correlated with O₃.（5）The boundary layer ventilation coefficient was negatively correlated with the concentrations of PM_2.5.5 and SO₂ in Beijing and Guangzhou,and positively correlated with O₃.The vertical velocity was positively correlated with the concentrations of PM_2.5.5 and SO₂ and O₃ in Beijing and Guangzhou.There was a positive correlation between dew point temperature and the concentrations of PM_2.5.5 and SO₂ and O₃in Beijing,there was a negative correlation with the concentrations of PM_2.5.5 and SO₂ and O₃ in Guangzhou.（6）Based on the optimization of meteorological parameters of air pollution,adopting high spatial resolution NCEP/NCAR GSP numerical forecast products,using hourly air pollutant concentration data and stepwise regression methods,the best predictors were selected,and a three-hour,0-72 hour short-term refined air pollutant concentration forecast model was established in temperate Beijing and tropical Guangzhou.The tendency to increase or decrease the concentrations of PM_2.5,SO₂,and O₃ pollutants as the boundary layer meteorological conditions increase or decrease can provide reference and technical support for the production of refined and comprehensive air quality forecasts that consider meteorological factors,the test can be applied to local air quality forecast work.