Monitoring And Analysis Of VOCs Pollution In Atmosphere Of Liaodong Bay District

The problems caused by environmental pollution have been increasing as the rapid development of industrialization,and it has become an important challenge for countries all over the world since the 21 st century.Volatile organic compounds(VOCs)refer to a class of organic substances with a lower boiling point at normal temperature,which are easily volatilized into the atmosphere and pose serious threats to the health of humans,animals and plants.Meanwhile,they have a high atmospheric oxidation potential and can participate in atmospheric chemistry.Thus,they are important precursors of photochemical smog and particulate pollutants,and they are the key monitoring objects of regional air environmental pollution as well.Panjin City is an important petroleum and petrochemical industrial base in China and one of the important central cities in the Liaoning coastal economic belt.It has dense highways and road networks.Continuous observation of VOCs in the air of Panjin Liaodong Bay area can reflect the local air quality and provide a strong basis for future development of relevant control policies.The main contents of the present study are as follows:(1)Through continuous sampling at the sampling point of the Panjin Liaodong Bay for one year,the VOCs in the area were analyzed.The fluctuation of VOC levels varied the most in summer but the least in winter,and a daily bimodal distribution was observed.The analysis of VOCs showed that(1)VOCs in this region were mainly alkanes,followed by olefins;(2)variations between samples collected at day and night indicated alkanes and the aromatic hydrocarbons was slightly higher at night than in the daytime,and the day-night variation of olefins fluctuates less than the others;(3)as the region was located in the main traffic line,and the variation of VOCs showed an obvious weekend pattern.The variation of VOC concentrations under different meteorological conditions such as wind speed,rainfall and pressure were investigated,and the pollution sources of VOCs in this area were analyzed.(2)Through the continuous monitoring of the ozone concentrations at the sampling points located,the relationship between ozone and premise of the VOCs was investigated.The ozone concentrations were higher in summer and autumn,whereas lower ozone concentrations were observed in spring and autumn.The pattern of daily variation showed an obviously single peak.The lower pressure would produce higher ozone concentration.Comparing the changes of VOCs and ozone,it was found that daily peak value of ozone appeared after the peak of TVOC,and there was a lag behind time and inter-relationship between these two typical pollutants.The health risk assessment of VOCs was carried out accordingly.