| Aerosol particles suspended in the atmosphere will play an important role in impacting local air quality, human health and global change. At present domestic main observations are set on the economic developed zones and megacities. Research are also focused on particle pollutants such as vehicular traffic, coal combustion in northern inland area. However, knowledge of the characteristic of particles pollution derived from typical natural and anthropogenic activities especially from emergency events in the southern coastal area is still scarce. Using advanced on-line aerosol mass spectrometric technology, we study and analysis the chemical composition of atmospheric aerosols over Xiamen during episodically events.Xiamen, a subtropical and harbor city, was affected by northwest typhoons, meanwhile it is one of famous tourist cities in southeastern China. During holidays, thousands of tourists and vehicles come to Xiamen and result serious air pollution. These unique geographical location make Xiamen an ideal place to sample during typical events. In this paper, we combine the AMS advantage in providing quantitative composition of non-refractory aerosol with the SPAMS in characterizing of single particles, acquiring abundant data during the typhoon ?Soulic? and long national day holiday in order to investigate how affect aerosol components during episodically events. Several conclusions are listed as follows:1. A single particle aerosol mass spectrometer was used to investigate variations of chemical species in fine aerosol particles during the typhoon ?Soulik? transiting over Xiamen, an island in the southern China. The results revealed that the vanadium-rich type emitted from ship was obvious in an increased trend near typhoon arrival due to a large number of ships anchored on docked in the Xiamen harbor in order to avoid the typhoon. Counterclockwise flowed air brought inland pollutants to Xiamen, resulting in peak of particles pollutants in number concentration. Great rain storm would washout the particulate matter quickly to very low concentrations with all the chemical specials during the typhoon arrived. However after thetyphoon, the particle number concentration in the atmosphere increased rapidly. Calcium-containing particles from the burning of lubricating oil and cement were most pronounced of number concentration increasing after the typhoon, showing that automobile exhaust and cement were still important sources of local pollution in Xiamen.2. An aerodyne aerosol mass spectrometer(AMS) and single particle aerosol mass spectrometer(SPAMS) were deployed in Xiamen island from Sep.23 to Oct.16 to characterize the concentration, size distribution, temporal and spatial variations and mixing state. Due to larger number of tourists and vehicles come into Xiamen island, the total NR-PM1 concentration increase from 9.94 mg/m3 to 22.23mg/m3, which was dominated by sulfate and organics aerosol. At the same time, through on-line measurements by SPAMS and statistical analysis, we examine four types of organic aerosol: one particle type, vanadium-containing(V), originating from heavy oil combustion, was associated with boat and heavy truck. A secondary particle type, composed of element carbon and sulfate species(called EC-SO4), was found enhanced in particle number concentration at noon periods. A third particle type, aromatic compounds mixing with sulfate and nitrate(called aromatic-SO4-NO3), was found to peak both in the morning and evening, which was associated to traffic related volatile aromatic compounds. A fourth particle type(high-molecular), exhibit the same trend like aromatic-SO4-NO3 was attributed to traffic-related and ship emission volatile compounds. The results show that, due to the high temperature and intensity light, organic aerosol shows secondary organic aerosol?s properties. Besides, the aerosol over Xiamen are acidic, especially during the national day holiday, the acidity is more than others.3. A single particle aerosol mass spectrometer was deployed in June and November 2013 to characterize the nitrate-containing particles in Xiamen. In summer and winter, about 65.2% and 68.7% of the mass spectra particles contained higher nitrate ion peaks, respectively. The results revealed that the cluster of sea-salt was obvious due to air from the marine waters predominated and EC and OC particles were relatively smaller and fresher in summer. However, the persistent northeastmonsoon during the winter period brought pollutants emitted from the potential sources regions in the southeastern China, resulting in elevating number concentration of K-rich and ECOC types. The peak intensities of nitrate during the near noon and good correlation between nitrate and ammonium(R2=909 and 0.917) suggest that the major of nitrate is formed by photochemical reactions of NO2. However, in winter another nitrate peak during night showed in additional source above, heterogeneous reactions of N2O5 on the aerosol surface dominated the particulate nitrate formation in night... |
PDF Full Text Request