[Spatial Distribution Characteristics of VOCs and Its Impact on Ozone Formation Potential in Rizhao City in Summer].

GC-SAW was used to carry out online sampling analysis of the main business sources, residential sources, and roads in Rizhao City from August 22 to 29 in 2020. The spatial distribution characteristics of various volatile organic compounds (VOCs) in the atmosphere were obtained, and the chemical reactivity of the main components was studied. The results showed that the VOCs with carbon atoms greater than 5 (VOCC>5) were mainly toluene propylbenzene and n-octane, and the spatial distribution was significant; the average ρ(TVOCC>5) in the port area, downtown area, and industrial area were 80.5, 115.3, and 118.1 µg·m-3, respectively. Combined with road traffic impact and industrial production emissions, the maximum ρ(TVOCC>5) on the main roads in Rizhao City appeared near the Yingbin Road; the concentration value was 164.37 µg·m-3; the ρ(BTEX) in adhesive processing, painting, and glass factories reached 432.34, 1010.84, and 1989.85 µg·m-3, respectively. The chemical reactivity analysis of the main components of VOCC>5 showed that BTEX and n-octane were the important active components of ozone formation in Rizhao City.

[Analysis of Chemical Composition, Source and Evolution of Submicron Particles in Xianghe, Hebei Province].

Haze formation is closely related to the chemical composition of fine particles. An aerosol chemical speciation monitor (ACSM), aethalometer, etc. were used to investigate the chemical components、 source, and evolution of submicron particles at Xianghe, a suburban site located between the megacities of Beijing and Tianjin from May 31 to June 30, 2013. The results suggest that the air quality in Xianghe has suffered severe deterioration, which is imminent to improve air quality and pollution. On average, PM1 accounted for ~71% of PM2.5 and PM1 distributed in 20-80 µg·m-3 mainly. Organic aerosols had a high degree of oxidation. Significant straw burning events were observed during June 2013 in Xianghe. During the straw burning period, the mass concentration of PM1 significantly increased and the mass fraction of organic aerosols in PM1 rapidly increased to about 47%, on average. The contribution of nitrate was generally greater than that of other inorganic components. Affected by the straw burning events, the aerosol acidity turns from weak alkaline to weak acid. Positive matrix factorization was performed on the ACSM OA mass spectra, which identified two primary OA (POA), i.e., BBOA and HOA, and two secondary OA (SOA), i.e., LV-OOA and SV-OOA, factors. The SOAs dominated the OAs during the observation, contributing ~69% of OAs. However, after the straw burning period was removed, the positive matrix factorization (PMF)results did not reveal biomass combustion organic aerosols.

Characteristics and seasonal variations of PM2.5, PM10, and TSP aerosol in Beijing.

OBJECTIVE: To investigate the seasonal characteristics and the sources of elements and ions with different sizes in the aerosols in Beijing. METHODS: Samples of particulate matters (PM2.5), PM10, and total suspended particle (TSP) aerosols were collected simultaneously in Beijing from July 2001 to April 2003. The aerosol was chemically characterized by measuring 23 elements and 18 water-soluble ions by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and ion chromatography (IC), respectively. RESULTS: The samples were divided into four categories: spring non-dust, spring dust, summer dust, and winter dust. TSP, PM10, and PM2.5 were most abundant in the spring dust, and the least in summer dust. The average mass ratios of PM > 10, PM2.5-10, and PM2.5 to TSP confirmed that in the spring dust both the large coarse (PM > 10) and fine particles (PM2.5) contributed significantly in summer PM2.5, PM2.5-10, and PM > 10 contributed similar fractions to TSP, and in winter much PM2.5. The seasonal variation characteristics of the elements and ions were used to divide them into four groups: crustal, pollutant, mixed, and secondary. The highest levels of crustal elements, such as Al, Fe, and Ca, were found in the dust season, the highest levels of pollutant elements and ions, such as As, F-, and Cl-, were observed in winter, and the highest levels of secondary ions (SO4(2-), NO3-, and NH4+) were seen both in summer and in winter. The mixed group (Eu, Ni, and Cu) showed the characteristics of both crustal and pollutant elements. The mineral aerosol from outside Beijing contributed more than that from the local part in all the reasons but summer, estimated using a newly developed element tracer technique.