[Emission Characteristics of Gas-and Particle-Phase Polycyclic Aromatic Hydrocarbons from Cooking].

Polycyclic aromatic hydrocarbons (PAHs) play a key role in the formation of secondary organic areole and ozone. This study sampled three commercial Chinese restaurants and a food plant in Shenzhen to analyze the emission characteristics of PAHs, especially the alkyl PAHs in both gas and particle phases. The results showed that the ρ(total PAHs)in the particle and gas phase were (1381.6±140.5) ng·m-3, (1030.2±116.4) ng·m-3, (908.3±111.9) ng·m-3, and (838.0±93.5) ng·m-3 in the food plant, Sichuan, Cantonese, and Zhejiang restaurants, respectively. More than 60% of the PAHs were distributed in the gas phase, especially the lower molecular weight PAHs (lower than Chrysene). The gas phase proportion of naphthalene was the highest, with over 75% of it distributed in the gas phase. However, the PAHs with a higher molecular weight than that of benzo(b)fluorescence were mainly distributed in the particle phase. The total concentration of alkyl PAHs emitted from cooking was much lower than that of the corresponding parent PAHs, and the distribution characteristics of alkyl PAHs were quite different from those of other emission sources. The linear fitting of lgKp and lgPL showed that the slopes of the three commercial restaurants ranged from -0.25 to -0.28, whereas for the food plant, the value was -0.18, which indicates that the gas-particle partitioning of PAHs were not in equilibrium.

[Review of Screening and Applications of Organic Tracers in Fine Particulate Matter].

Specific organic compounds within atmospheric particulate matter are indicators of specific pollution sources and, as such, can be used to differentiate inputs from various air pollution emissions sources in urban areas. Therefore, many studies have been conducted to detect organic particulate matter and screen the associated organic tracers that provide provenance information. This review provides a brief summary of the emission characteristics of biomass burning, cooking, fossil fuel combustion, and traffic. The particular marker compounds that carry provenance information for these four emission sources are discussed and diagnostic ratios are calculated to discuss the use of organic tracers in source apportionment. The shortcomings and new directions of using source tracer screening are also discussed.

[Emission Characteristics of Particulate Organic Matter from Cooking].

Cooking is an important source of atmospheric particulate organic matter (POM). In this study, four Chinese restaurants in Shenzhen (west style, dim-sim restaurant, worker's canteen, and Korean cuisine) were sampled to examine the chemical composition of POM and research molecular tracers. The result showed that more than 60% of the PM2.5 mass was due to organic compounds. For the quantified organic compounds, the results indicated that fatty acids, dicarboxylic acids, and n-alkanes were the major organic compounds emitted from all cooking styles, PAHs, sterols, and monosaccharide anhydrides were found at relatively low levels. The composition of POM was strongly influenced by cooking style. The cooking styles of the west and Korean restaurant emitted the most abundant fatty acids, n-alkanes, and PAHs, but the least sterols and monosaccharide anhydrides, whereas the dim-sim restaurant and worker's canteen displayed the opposite results. The values of Fla/(Fla+Pyr) and LG/(Gal+Man) provided candidate tracers for cooking because they were less influenced by the cooking styles and were significantly different from other pollutant sources. Furthermore, cooking contributed significant amounts of fatty acids and dicarboxylic acids to atmospheric PM in Shenzhen.

[Pollution characteristics and health assessment of particulate mercury in Hebei rural households].

Environment problems in rural areas have been increasing dramatically in recent years. Atmospheric particulate mercury has posed increasingly obvious threats to human health. However, there were few studies attaching importance on mercury pollution in rural residential environment. Taking particulate mercury as research objects, the studies in six villages of Hebei Province were carried out in July/August 2009 and October/September 2010. A number of PM10 and PM2.5 samples were taken in 34 typical households, using cold vapor atomic fluorescence to determine the content of particulate mercury. The results showed that the mercury concentration in PM10 in kitchen was about twice that in the courtyard. In the same space, the mercury contents in PM10 in a descending order were as follows: winter (3.004 ng x m(-3)), autumn (1.550 ng x m(-3)), summer (1.127 ng x m(-3)); in the same season, the mercury levels in PM2.5 in a descending order were as follows: kitchen (0.795 ng x m(-3) +/- 0.337 ng x m(-3)), living room (0.398 ngx m(-3) +/- 0.159 ng x m(-3)), yard (0.321 ng x m(-3) +/- 0.143 ng x m(-3)); the Mercury content in PM2.5 accounted for (52.4 +/- 13.5)% of that in PM10. Evaluation of the health risks of mercury in PM2.5 revealed that children were exposed to the highest level, whose average annual excess risk was below 10(-8). Therefore, the health risk of peasants living in rural residential environment was at a negligible level.

[Hourly measurement on aerosol NH3 and gas NO(x) emission in the rice field].

Aerosol NH3 and gas NO(x) are the major components in atmospheric particles and precipitation, which are key precursors to form aerosols. The intensive N fertilization in arable land is an important source of aerosol NH3 and gas NO(x), which have not been well characterized yet. During May to October in 2010, the characteristics of aerosol NH3 and gas NO(x) emission from rice field after urea application were investigated. The time resolutions of measurements were set to be one hour. The aerosol NH3 emission and metrological factors within 20 d of continuous sampling after fertilization in four experiments were monitored. The experiment on gas NO(x) emission and metrological factors influencing the emission were carried out from the beginning of the forth test, which lasted for 47 days. Results indicated that the aerosol NH3 emission factors of four tests were 2.6%, 5.5%, 4.0% and 1.6%, respectively. The corresponding aerosol NH3 emission flux of four tests were 3.97, 2.08, 1.52 and 1.22 kg x hm(-2), respectively. Temperature (air temperature and soil temperature) was found to be the main factor influencing aerosol NH3 emission in rice fields after fertilization, while the impacts of air humidity and soil moisture were not clear. After analyzing the monitoring data, it can be concluded that the ratio of the emission amount of NO2 -N and NO-N in rice fields after fertilization was 9/4; the emission factor and the emission flux of gas NO(x) were 0.14% and 0.30 kg x hm(-2), respectively. The relationship between metrological factors and gas NO(x) emission flux was also examined.

[In-situ measurement on volatilization loss of ammonia in the vegetable field and its influencing factors].

In order to obtain ammonia volatilization flux and volatilization loss rate in the vegetable field and investigate their relationship with environmental factors, an on-line monitoring system was used to measure the ammonia volatilization in the vegetable (Brassica rapa L. and lettuce) field after urea application during January to September, 2009. The system included a wind tunnel system, a gas collector and an online analyzer system with ion chromatography. The time resolution of measurement was 15 min. The recovery of the system was (92.6 +/- 3.4)%; the accumulated ammonia volatilization within 15 d continuous sampling after fertilization was regarded as the total loss. The accumulated ammonia volatilization of 12 d continuous sampling after fertilization accounted for (85.4 +/- 5.2)% of the total volatilization. The ammonia volatilization loss of broadcasting basal dressing and top dressing for Brassica rapa L. were 23.6% and 21.3%, respectively. The ammonia volatilization loss of holing basal dressing and top dressing for lettuce were 17.6% and 24.0%, respectively. The ammonia volatilization in the vegetable field mostly occurred in the first 2-3 weeks after fertilization. The ammonia volatilization flux had significant positive correlation with the nitrogen application rate, while the ammonia volatilization loss rate had negative correlation with the nitrogen application rate. The ammonia volatilization flux was positively correlated with the soil temperature (r = 0.041, p < 0.05) and the air temperature (r = 0.049, p < 0.01), while not significantly associated with the air humidity and the soil moisture. Temperature was found to be a main factor influencing the ammonia volatilization in the vegetable field.

[Validation of a prediction method for indoor air pollution].

The validation study of the prediction method for indoor air pollution was carried out by comparing the results of emission models based on data obtained in a large and a small emission chamber, with actual measured concentrations. A new decorated room was studied as a case. Emissions of complicated objects and simple surface layer materials were studied respectively in the large and small chamber and emission models were developed. Those models were based on the assumptions regarding mass conservation of substances and the hypothesis that pollutants were well mixed. The emissions of formaldehyde and TVOC (total volatile organic compounds) in the studied room were predicted by the method. The predicted concentration trend of pollutants was in accordance with the measured trend when some air exchange (0.03 ACH, air change per hour) was taken into account. The normalized standard errors of formaldehyde and TVOC pollution prediction were respectively 2.8% and 1.6%. Modeling analysis shows that the contribution to total formaldehyde pollution of the studied room was: furniture > paint > floor; the contribution to total TVOC pollution was: paint > floor > furniture. The results lead to the conclusion that this prediction method can well describe the pollution trend, can assess the contribution of different sources, can guide the choice of building materials and is an effective tool for indoor air pollution assessment and control.

Approach to and effectiveness of environmental risk education of public: case of indoor environmental risk consciousness in beijing.

Increasing concern regarding environmental risk in China has led to a need for education on environmental health and safety. In this paper, we report on four main ways to enhance environmental risk consciousness of the public. By investigating residents' indoor environmental risk consciousness in Beijing, we appraised the effectiveness of current environmental risk education approaches. Our investigation showed that the indoor environmental risk consciousness of most residents is high. Most residents have some environmental risk knowledge, have a strong desire to demand better quality of their living environment, and would like to invest in it. However, people's actual behavior in terms of reducing health risk factors fall comparatively behind. It is important to use all approaches to carry out environmental risk education. Not only should new knowledge be imparted, but the public should also be trained how to take precautions against pollution. The extension of education from campus to society is also necessary.