Emission Characteristics Of Oxygenated Volatile Organic Compounds (OVOCs) From Solvent Use Sources

The high concentration ozone（O₃）and the fine particulate matter(PM_2.5)pollution have become an increasingly serious atmospheric environmental problems in many areas of China.Volatile organic compounds（VOCs）in the atmosphere are the key precursors of the formation of near surface O₃ and PM_2.5.Oxygenated volatile organic compounds（OVOCs）as an important trace component in troposphere,it is necessary to carry out basic research on the source of OVOCs.It is helpful to understand the chemical process and importance of OVOCs in the atmospheric environment and provide important scientific support for improving air quality and controlling OVOCs emission in the next step.The emission of solvent use is a typical pollution source in China,especially in urban areas,with the rapid development and application of organic solvents,it is very important to study the OVOCs in the solvent use.This study conducted a field campaign on the typical industries of VOCs emission from typical solvent use sources in Pearl River Delta（PRD）.Five representative enterprises including shoe making,furniture manufacturing,printing,plastic surface coating and shipbuilding industry were selected.The OVOCs online monitoring and testing platform was built in the emission sources of solvent use,and use the advanced high resolution on-line measurement technology of proton transfer reaction time-of-flight mass spectrometry（PTR-To F-MS）was carried out.Based on the on-line measurement by PTR-To F-MS,the typical emission species in solvent sources can be identified in real time,quickly and accurately.It is found that OVOCs,such as acetone,isopropanol,ethyl acetate,etc.,and aromatic hydrocarbons,such as toluene,xylene,etc.,emission more in solvent use,which is highly related to the use of raw and auxiliary materials.Besides,we can also identify many OVOCs,most high molecular weight compounds,such as esters and so on,which are widely used in solvent industry and have received little attention in previous studies.However,full spectrum measurement of PTR-To F-MS can quantify these substances.According to the results of various industries,it is found that isopropanol,acetone,butanone,ethyl acetate and other substances have a great contribution in most industries,which is highly consistent with the raw and auxiliary materials used by enterprises in various industries,such as the use of adhesives,cleaning agents,water-based solvents,etc.,and also has a certain relationship with the treatment efficiency of the treatment device.However,the source composition spectrum of all substances is classified according to species characteristics.It is found that OVOCs accounts for the largest proportion in most industries（all over 65%except for shipbuilding industry,the highest for the plastic surface coating is 96.8%）,while the shipbuilding industry has high requirements on coating,and still uses solvent coating,and the most important emission component is aromatic hydrocarbon（79.6%）,while OVOCs only accounts for the18.1%.In the fugitive emissions,the contribution of OVOCs is lower than that of the stack emissions,the highest proportion is traditional printing（85.8%）,while OVOCs in shipbuilding is lower,only 11.1%,and the most important contribution is still aromatic hydrocarbons,reaching 86.0%.Compared with previous studies,the emission of OVOCs in typical industries is underestimated.At the same time,the full spectrum measurement of PTR-To F-MS can quantify more OVOCs species,which provides data support for establishing a more comprehensive solvent use source profiles covering OVOCs components in PRD localization.This also indicates that OVOCs should be paid more attention in the future research on solvent use.