Methods Of Carbon Isotope Analysis For Atmospheric Carbonyl Compounds And The Study Of The Organic Pollution

Currently, the issue of environment pollution is more and more serious, so the environmental research and protection is an urgent. Carbonyl compounds ubiquitous constituents presence in the atmosphere are of great concerned with regard to their adverse effects on human health, such as toxic, mutagenic, possible carcinogenic effects, photochemical properties. Carbonyl compounds have well-known both of anthropogenic and biogenic origin.In this dissertation, two methods have been successfully developed for the compound-specific carbon isotope analysis of atmospheric carbonyl compounds using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). These methods allow the determination of δ13C in organic substances at the nanogram level, and the reproducibility and precision of the measurements are excellent.one method is that the atmospheric carbonyl compounds are collected using the conventional 2,4-dinitrophenylhydrazine (DNPH) derivatization method and their δ13C values are calculated based on stoichiometric mass balance after measuring the carbon isotopic compositions of the carbonyl-DNPH derivatives and DNPH, respectively. Using formaldehyde, acetaldehyde, acetone and DNPH standards with their δ13C values predetermined, the δ13 C fractionation is evaluated for derivatization processes both in solution and in simulation experiment of atmospheric sampling. In these two derivatization systems, through reduplicate δ13C analysis, good reproducibility of the derivertization process is found and the results indicate that the derivatizaion process introduces no isotopic fractionation for formaldehyde, acetaldehyde and acetone. Thus the δ13C values of the original underivatized carbonyls can be accurately calculated through a mass balance equation. Using the method developed, preliminary tests of atmospheric formaldehyde and acetaldehyde at two urban sites were conducted and revealed significant differences of their isotopic compositions. In addition, the method was used to help us understand the primary emission, secondary formation and removal processes of carbonyls in the atmosphere of the Prince Hill Forest Park and two restaurants, HuaDu District of GuangZhou, China.Another one is that the atmospheric formaldehyde was collected using a Sep-Pak Silica Gel NaHSO3 coated cartridge, then derivatized by cysteamine of known δ13C value and the δ13C value of their derivatizative was determined by GC/C/IRMS. The δ13C value of atmospheric formaldehyde was calculated through a simple mass balance equation between formaldehyde, cysteamine and their derivatizative. In order to evaluate the reproducibility, the accuracy and the carbon isotopic effect during the sampling and derivatization procedures. Reduplicate simulated experiment showed that the reproducibility of these processes were excellent. This study also showed that no carbon isotope fractionation occurred during the processes. The accuracy and precision of the method are of the same quality as the reproducibility of the measurements. Using the method developed, four atmospheric formaldehyde samples were collected and results showed that the δ13C values of atmosphericformaldehyde were distinctly difference between daytime and nighttime.The two methods were proved to be suitable for routine operation. Hence the technique will be a very valuable tool to complement concentration measurement of atmospheric carbonyl compounds and provide valuable additional information on sources and sinks of atmospheric carbonyl compounds.Additionally, in the presented dissertation, the source and diurnal variation of atmospheric concentration of carbonyl compounds and volatile organic compounds (VOCs) in the Prince Hill Forest Park, and the source and the characteristics of atmospheric concentration of carbonyl compounds and VOCs in two restaurants, HuaDu District of GuangZhou, China were discussed.The most abundant carbonyl compounds were acetone, formaldehyde, m/o-tolualdehyde and acetaldehyde and the most abundant VOCs were 1,2,4-trimethylbenezene, methylcyclopentane, isoprene and o-ethyltoluene in the Prince Hill Forest Park, HuaDu District of GuangZhou, China. Most carbonyl compounds had higher concentration in the daytime than midnight, on the contrary, most of VOCs had higher concentration in the midnight than daytime. It might be because photo-oxidation and biogenic sources played important role on concentration of carbonyl compounds and VOCs in daytime and nighttime. The results indicate that the biogenic and photo-chemical sources were the main factor which effected the concentrations of carbonyl compounds.The sources and the characteristics of atmospheric concentration of carbonyl compounds and VOCs in YX restaurant and JH restaurant, HuaDu District of GuangZhou, China are discussed. The results show that the concentration of carbonyl compounds in dinning room(indoor) at YX are higher than the dinning room(indoor) at JH, however the concentration of VOCs were lower than those of JH. The results indicate that the characteristics of atmospheric concentration of carbonyl compounds and VOCs in the two restaurants are due to the different cooking styles. Foods are the main source of the atmospheric carbonyl compounds. The concentrations of most carbonyl compounds and VOCs in indoor were higher than outdoor at the two restaurants, especially formaldehyde, acetaldehyde, acetone, α-pinene and β-pinene. The characteristics of atmospheric concentration of carbonyl compounds are the same at outdoor environment of the two restaurants. However, due to the different sampling time, the characteristics of VOCs are different at outdoor environment of the two restaurants. The main sources of carbonyl compounds and VOCs at outdoor environment are photochemical oxidation of gas-phase hydrocarbons and auto exhaust emissions.