The implication of carbonaceous aerosol to the formation of haze: Revealed from the characteristics and sources of OC/EC over a mega-city in China

As the largest Chinese city by population and the largest city proper by population in the world, Shanghai has frequently suffered the heavy haze in recent years. In this study, the observational data (PM 2.5 , PM 10 , O 3 , NO 2 , CO and SO 2 ) at the ten urban monitoring stations in Shanghai from November 25 to December 9, 2013, were used to analyze the haze pollution. The source contributions of PM 2.5 in Shanghai were identified by trajectory clustering and hybrid receptor models (potential source contribution function (PSCF) and concentration weighted trajectory (CWT)). The results showed that for the whole study period, the ranges of pollutant concentrations are 2. . It was found that PM 2.5 contributed more than 80% of PM 10 for the whole period except the relatively clean period in which only 45% of PM 10 is PM 2.5 . The model analyses show that clean air masses reaching at Shanghai were from the far away regions like Mongolia and Inner Mongolia with the high mean wind speed (fast air masses). On the other hand, the heavy haze air masses were mainly from the nearby industrialized and urbanized provinces with industrial cities. It was found that the formation of the extremely heavy haze from December 5 to 7 in Shanghai was mainly because of the air pollution transported from the nearby provinces (i.e., Anhui, Jiangsu, Zhejiang) and central part provinces (such as Shandong, Hebei) of eastern China. The correlation analyses among PM 2.5 and other pollutants show that the PM 2.5 formation in Shanghai is affected by the sources similar to those of CO such as combustion, industry, mobile and oxidation of hydrocarbons. Finally, the controlling strategies are discussed on the basis of this result.

Section: Source Contributions Based On Pscf and Cwt Analyses For Pm 25mentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Heavy Haze Episode in Shanghai in December of 2013: Characteristics, Origins and Implications

Yan

Fan

et al. 2015

“…Model 2001, Atmoslytic Inc., Calabasas, CA, USA). A 0.5 cm 2 punch of each sample was analyzed for eight carbon fractions following the IMPROVE A protocol (Hou et al, 2011).…”

Section: Data Sources and Treatmentmentioning

confidence: 99%

Effect of Aerosols on Visibility and Radiation in Spring 2009 in Tianjin, China

Hai

Zhang

et al. 2012

Meteorological and aerosol data were measured at the atmospheric boundary layer observation station in Tianjin, China, and were analyzed to study the effects of aerosol mass, composition, and size distributions on visibility and short-wave radiation flux. The results show that fine particles played important roles in controlling visibility in Tianjin. The major contributors to light extinction coefficients included sulfate (28.7%), particulate organic matter (27.6%), elemental carbon (19.2%), and nitrate (6.1%). In addition to the measurement of aerosol composition, the size distribution of aerosol number concentrations were also measured and classified between haze days and non-haze days during spring. The extinction characteristics of ambient aerosol in haze days and non-haze days were calculated using Mie theory model. The average extinction coefficient and scattering coefficient of atmospheric aerosols were 0.253 1/km and 0.213 1/km in non-haze days, while 0.767 1/km and 0.665 1/km in haze days. A radiation transmission model LOWTRAN7 is also applied in this study. The model calculated radiant flux densities in haze days and non-haze days, which showed a fairly agreement with the observation results, showing that the heavy aerosol loadings in Tianjin had significantly impact on atmospheric visibility and radiation fluxes.

“…Carbonaceous aerosol is a crucial factor for haze formation because it reduces visibility and exhibits high concentrations during haze episodes . In China, several studies have investigated the effects of carbonaceous aerosols on megacities and mountains (Cao et al, 2009;Duan et al, 2005;Hou et al, 2011). In addition, some studies have focused on river deltas (Cao et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Influence of Seasonal Variation and Long-Range Transport of Carbonaceous Aerosols on Haze Formation at a Seaside Background Site, China

Sui

Yang

et al. 2015

The Yellow River Delta is a crucial background site that is located in a heavily polluted area in China. Carbonaceous aerosol concentrations were measured using 2.5-µm-diameter particle (PM 2.5 ) samples collected from the Yellow River Delta, Shandong Province, China, from January 2011 to November 2011 by using the thermal/optical reflectance method. In the Yellow River Delta, the organic carbon (OC) concentration ranged from 0.74 to 27.51 µg/m 3 ; the annual average concentration was 7.61 µg/m 3 . Moreover, the elemental carbon (EC) concentration ranged from 0.16 to 15.00 µg/m 3 ; the annual average concentration was 2.98 µg/m 3 . In addition, the carbonaceous aerosols concentrations were the highest in winter and lowest in summer. The EC tracer method showed that the secondary OC (SOC) contribution to the total carbonaceous concentration tended to be higher in winter than in other seasons. An analysis of carbonaceous showed that haze was derived from different matter in different seasons, particularly haze in winter was dominated by OC, EC, and SOC. The Yellow River Delta can be considered a background site because of the strong correlation between OC and EC (R 2 = 0.83-0.97). Furthermore, the OC/EC ratios for cold seasons (winter and spring) were higher than those for warm seasons (summer and autumn), suggesting that the OC originated from biomass burning in nearby villages in cold seasons. Back trajectories indicated that short-distance air mass from region area contribute most to the sample site. However, the highest carbon concentrations during haze days were related to the air mass travelled through the Bohai Rim except in summer haze episodes. Based on the entire sampling period, the air mass travelled through the polluted areas of Beijing and Hebei Province toward the Yellow River Delta may contribute most to carbonaceous species due to long-range transport.