Characteristics And Sources Of Atmospheric Pollutants In Winter Of Jinan

In order to investigate the atmospheric pollution characteristics and the primary cause to from haze in winter of Jinan, a comprehension observation was carried out in Jinan during November23to December7in2009. The gases pollutants, NOx, NOy, SO2, O3and CO and meteorological parameters were measured during this observation. Meanwhile, the concentrations of BC and PM2.5were obtained by BC analyzer (AE-21) and tapered element oscillating microbalance analyzer (TEOM8500). Particle size distribution were also measured by Wide-rang Particle Spectrometer(WPS1000XP). Two haze episodes were observed in the observation. From WS/WD, RH, visibility, diurnal variation of speries, correlation analysis among speries particle size distributions, it can be draw conclusions as followed:1. According to the visibility and concentrations of pollutants, we divided this observation into three periods:November25to November26was called as haze episode1, during December1to December2was called as haze episode2, and the other period of the observation were called as non-haze days.2. The average concentrations of PM2.5, NOx and SO2and were171.3μg/m3,106.6ppb and54.3ppb. The concentrations of PM2.5was2.3times higher than National Ambient Air Quality Standards (daily standard), and NOx and SO2was2.2,1.0times higher than National Air Quality Standards (daily standards). While in haze episodes, the concentrations of PM2.5, SO2and NOx reached222.1μg/m3,157.9ppb and74.4ppb, which were1.8,1.7and1.8times compared to those on the non-haze days.3. Serious air pollution in the winter of Ji’nan was probably contributed to three factors:(1) Large regional emissions of SO2and NOx. In Shandong Province, emissions density of SO2and NOx were4.7and5.0times compared to the average levels in China. In this case, Ji’nan is easily suffered from serious air pollution.(2) Domestic heating in winter. In North China Plain, from15November to15March next year, there is a supply to domestic heating. The fraction of Ji’nan’s coal consumption for domestic heating in total coal consumption in winter can be23.2%in2008assuming that there is the same fraction in Ji’nan as that in whole Shandong province, which further exacerbates air quality of winter in Ji’nan.(3) The unique topography. Ji’nan is a typical inland city, surrounded by mountains on three sides, east, west and south sides, which doesn’t favor the diffusion of pollutants in winter prevailing in northeast wind.4. Winds prevailed in north/northeast with relative high wind speed, which brought pollutants to the sampling site in haze episode1, and obvious pollution from the influence of coal-fired emission in northeast, along with the vehicular exhaust emission in the episode1. While in episode2winds were mainly from south with very slow speed or almost calm wind, pollution was characterized by the vehicular exhaust emission, along with the coal-fired emission. Compared to haze episodes, pollution was characterized by vehicular exhaust emission and diurnal variation of atmospheric diffusion.5. In haze episode1, the main sources of SO2and NOx were coal-fired emission and vehicle exhaustand emission, respectively, and most of PM2.5probably came from the emission of vehicular exhaust. In haze episode2, SO2and NOX were probably mainly came from the coal-fired emission and vehicular exhaust emission. As for PM2.5, it came from not only vehicular emission, but also coal-fired emission. There are relative high correlations among speries in non-haze days to haze episodes, suggesting more complex sources in haze episode.6. Average number concentration of particulate matter during the observation was10240#/cm3, for43%of Particle size distribution in Aitken mode, for25%and23%of Particle size distribution in50-100nm and100-500nm, respectively. For78%of Particle size distribution in UFPs totally, while for9%of Particle size distribution in nuclei mode. 7. Number concentrations of particulate matter in winter of Jinan were mainly in Aitken mode and accumulation mode. Not only in haze episodes but also in non-haze days diurnal variations of particulate matter were both showed the peaks in rush-hour, suggesting that particulate matter in Jinan were influenced by vehicle exhaustand emission.8. Meteorological conditions in haze episode1were favorable on air particles diffusion and caused dust at the same time. Meteorological conditions in haze episode2were benefit of new particulates generation. In comparison, there were similar characteristic of particle size distribution in munber concentration in haze episodes and non-haze days expect higher munber concentration in10-20nm in non-haze days was more higher than that in haze episodes. This phenomenon implied that there had enough solar radiation and favorable meteorological conditions to generate the new particles in non-haze days.