[Emission Characteristics of Residential Coal Combustion Flue Gas in Beijing].

Honeycomb briquet,biomass briquettes and bituminous coal from suburb of Beijing were chosen as testing samples to carry out combustion experiments. The characteristics of inorganic pollutant emission factors and VOCs emission factors released from the flue gas were studied. The results showed that under the condition of sufficient combustion, the average emission factors of SO2 from these three types of coal respectively were 1.50,1.91,1.62 kg·t-1;NOx 0.420,0.901,2.20 kg·t-1;CO 22.4,37.3,87.3 kg·t-1. Combustion emission factors of gaseous pollutants for NOx and CO were in the order of bituminous coal > biomass briquettes > honeycomb briquet. SO2 emission factors were in the order of biomass briquettes > bituminous coal > honeycomb briquet. The 2014 emissions inventory of the three civil coal combustion pollutants in Beijing was obtained. Bituminous coal emissions of SO2 was more than 5.5×103 tons,NOx was more than 7.5×103 tons,CO was more than 290×103 tons. All these coal types released more kinds and higher concentrations of volatile organic compounds in ignition phase and damp down stage. VOCs emission factor was the highest during ignition phase, followed by damp down phase.

[Correlation between acidic materials and acid deposition in Beijing during 1997-2011].

Based on the environment monitoring data and the ambient air quality data during the period of 1997-2011 from Beijing municipal environmental monitoring center, the correlations between primary pre-cursors of acid deposition, acidic materials and precipitation in Beijing area were analyzed in detail by taking economic development and energy mix into account. These results will be helpful for assessing the performance of environment quality improvement, as well as supplying scientific supporting information to make policies for national and local environment protection authorities. The main findings included as follows: there are significant correlations between the concentrations of NO2, NOx, and SO2 in the atmosphere, which indicated that both N and S in ambient air of Beijing came from fossil fuels combustion; acidic pollutants in the air are mainly discharged from local emission sources in Beijing, while there is no obvious correlation between S and N in wet deposition and concentrations of SO2, NO2 and NOx in the atmosphere, which demonstrated that concentrations of different ions in the acid deposition were influenced by both local sources as well as the inputs from other surrounding districts. Besides, the concentration of NO3- appeared to be correlative with the amount of motor vehicles, implying that the NOx from motor vehicles have contributed the increase of NO3- concentration of substantially.

[Characteristics of chemical compositions of precipitation in Beijing].

Characteristics of chemical compositions of precipitation in Beijing were analyzed. The average value of pH was 5.19 from 2005 to 2009, showing stable characteristics of acidification with precipitation. The lowest annual average pH was 4. 87 in 2008 with the highest acidification frequency of 42% and 23% in Chegongzhuang and Daxing districts respectively. The inorganic ion concentrations declined in 5a, indicating an increasing improvement of air quality in Beijing. The concentrations of NH4+ and NO3- were found to increase and contributed to the high nitrogen amount in precipitation. Different seasons have influence on composition concentrations. Generally speaking, the ion concentrations in winter were higher that that in summer. SO4(2-) was the main factor responsible for the acidification of snow in winter, SO4(2-) and NO3- had similar contributions to the acidification of precipitation in summer. It was also found that the local pollutants of SO2, NO(x) and NH3 were major contributors to the acidification of precipitation in Beijing area, local geological conditions and long-distance transfers have important effects on the neutralization of the precipitation.