Transformation Characteristics Of Volatile Organic Compounds From 1,3-Butadiene To Secondary Organic Aerosols

Volatile organic compounds(VOCs)is one of the important precursors forming haze,and its becoming increasingly prominent.For the scientific haze prevention it is of great significance that explore the transformation characteristics of VOCs into secondary organic aerosol(SOA).A typical VOCs-1,3-butadiene as the research object,which having high concentration and carcinogenic risk in pharmaceutical industry,simulated the behavior of 1,3-butadiene in atmospheric environment using the self-made FEP film smoke chamber,and explored the transformation process of 1,3-butadiene to SOA in combination with the FACSIMILE software.The conversion characteristics of1,3-butadiene under different influencing factors(ultraviolet,ozone concentration,relative humidity,seed aerosol and hydroxyl radical remover)were studied by IR real-time monitoring system.Research results show that:The photochemical reaction of 1,3-butadiene and ozone in the UV lamp rapidly generated and formed a large number of SOA,the formation rate of aerosol was 4.84 × 106number/mg,and the reaction rate constant was about 4.96 × 10-18 cm3/(molecule·s),the main gaseous products detected were CO,formaldehyde and acrolein(ACR).Facsimile software simulation 1,3-butadiene ozone oxidation products are ACR,ethylene,formaldehyde and CO and so on.UV and ozone can shorten the time needed to balance the gaseous/particulate products,promote the conversion of 1,3-butadiene to SOA,and have a certain influence on the size of SOA.When the relative humidity of 15%,55%,SOA generated coefficient were 4.84× 106 number/mg,4.83× 106 number/mg,respectively,which had little effect on the formation of SOA.Seed aerosols(anhydrous calcium chloride,sodium sulfate,sodium silicate,ammonium nitrate,etc.)have a detrimental effect on the formation of SOA,the order of influence was: ammonium nitrate> sodium silicate> calcium chloride,ammonium sulfate.Hydroxy remover(methanol,cyclohexane)has inhibitory effect on the 1,3-butadiene formation of SOA,methanol had a stronger inhibitory effect than cyclohexane.