[Contributions of Emissions Reduction and Regional Meteorological Conditions to Air Quality Improvement].

Regional meteorological conditions and emissions reduction are closely related to air quality. China has a monsoonal climate and regional meteorological conditions are significantly impacted by interannual climate variability. The objective of this study was to evaluate the contributions of meteorological conditions and emissions reduction to regional improvements in air quality. Trend analyses of key meteorological factors and air pollution for the Beijing-Tianjin-Hebei region, Chengdu-Chongqing region, Yangtze River Delta, and Pearl River Delta urban agglomeration areas were performed for the period from 2001 to 2018, and K-Nearest Neighbor (KNN) models were constructed for each calendar year. The analysis showed that approximately half of the years between 2001 and 2018 experienced abnormal global-scale climate conditions, i.e., El Niño and La Niña. Both emissions reduction and climate changes contributed to the improvement of air quality during the study period. The contribution of meteorological conditions to air quality improvement under abnormal climate conditions was 51% compared to 30% under normal climate conditions in the Beijing-Tianjin-Hebei region; for the Yangtze River Delta and Pearl River Delta regions, meteorological conditions contributed approximately 50% to the improvement of air quality under both abnormal and normal climate conditions. In addition, the contribution of emissions reduction to air quality improvement was higher in the study areas during 2015-2018 compared to 2001-2012. This indicates that emissions reduction has played an increasingly important role in air quality improvements largely due to the implementation of a variety of emission control measures. However, the contribution of meteorological conditions to air quality improvement cannot be ignored.

[Characterization of Metal Pollution of Regional Atmospheric PM2.5 and Its Sources Based on the PMF Model].

As important components of PM2.5, metal elements are extremely harmful to people and also have source specificity. Understanding the characteristics of PM2.5 metal pollution in the two different types of cities can help adjust the layout of regional industrial structure and improve the environment. PM2.5 samples during haze/non-haze periods were collected in Chengdu City and Renshou County. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the mass concentrations of eighteen metal elements in collected PM2.5 samples. The positive matrix factorization (PMF) model was used for source apportionment analysis for metal elements in PM2.5. The analysis showed that the ratio of trace elements from fugitive dust, motor vehicle emissions, and coal burning to the total elements is greater in Chengdu City than that in Renshou County. The proportion of trace elements from biomass combustion, industrial, and fuel sources in Renshou County is higher than that in Chengdu City. In addition, concentrations of Cd, As, and Cr in both areas exceeded the standards, indicating the occurrences of heavy metal pollution. During the haze period, the total concentrations of compositional metal elements in PM2.5 increased, although the rate was much lower than that for PM2.5. The ratios of elements between haze and non-haze periods ranged from 0.7 (Al) to 2.8 (Ba) in Chengdu City, and from 0.8 (Al) to 3.1 (Mn) in Renshou County. Among all metal elements, the increase rate for trace elements from coal burning and industrial activities was relatively large but small for those from fugitive dust, with the growth in trace elements from motor vehicles being modest. The results of this study indicated that the characteristics of pollution and source of metal elements in PM2.5 varied by economic scale, development mode, and industrial layout. In large cities such as Chengdu City, where economic development is mainly focused on tertiary industry, air pollution is mainly caused by transportation and urban construction, while in suburban area such as Renshou County, where secondary or heavy industry are the focus for economic development, the pollution is mainly affected by energy consumption and industrial production.

[Analysis of Activity and Its Emissions Trend for Construction Equipment in China].

Emissions from non-road equipment are attracting more attention due to their increasing contribution to air pollution. Thus, an accurate estimate of emission inventory for non-road equipment is imperative for air quality management and improvement. Activity data from a large range of construction equipment were collected from multiple sources, including on-site/phone interviews and literature review, and used for further analysis to characterize its operations. Activity analysis of construction equipment included:①activity of construction equipment by type (functionality); ②activity differences by geographical area; and ③activity differences by age. A back-propagation neural network model was developed to estimate the construction equipment population in China from 2018 to 2025. Furthermore, real-world measurements of emissions were made on 47 selected examples of construction equipment using a portable emission measurement system. Population, activity, and emission factors were then combined to develop emission inventories for construction equipment in China from 2015 to 2025. The results showed that activity of construction equipment differs by type or functionality, ranging from 1439 to 4332 hours per year. Furthermore, there are differences in activity by as much as three times due to geographical area differences for the same construction equipment type. In general, activity of construction equipment decreases as it ages by a rate of approximately 140 to 150 hours per year. It is estimated that CO, HC, NO, and PM2.5 emissions of construction equipment in China in 2015 were approximately 2.099, 0.462, 3.452, and 0.574 million tons, respectively. Compared to 2015, due to the slow growth of the construction equipment population, CO, HC, and PM2.5 emissions will decrease by 2.4%-33.1% and 7.1%-64.7% by 2020 and 2025, respectively, depending on pollutant. It should be noted that NO emissions appear to increase slightly for the first several years in the future, but then decrease after 2020. As increasingly stringent regulations have been enforced for on-road vehicles, but less has been done regarding non-road equipment, although total emissions from non-road equipment continue to decrease, their contribution to air pollution will continue to increase; they should therefore be one of the focuses for future work.

[Comparative Analysis of Pollution Characteristics of Carbonaceous Aerosol Components in the Atmosphere Between Urban and Suburban Areas].

To compare the pollution characteristics of carbonaceous aerosol components in the atmosphere between urban and suburban areas, Chengdu City and Renshou County were selected as study areas from which 88 samples of PM2.5 during haze and non-haze periods were collected and analyzed. Quantification of mass concentrations of PM2.5, carbonaceous aerosol components[organic carbon (OC), elemental carbon (EC), and secondary organic carbon (SOC)], along with correlation analysis of OC and EC, and principal component analysis (PCA) of carbon components were carried out. The results show that pollutant concentrations during the haze period were higher than those during the non-haze period. The OC and EC for Chengdu City and Renshou County were positively correlated, with their correlation coefficients during the non-haze period higher than those during the haze period. The ratios of SOC/PM2.5 in Renshou County were higher than those in Chengdu City during the haze period. This indicates that secondary aerosols play a more important role in haze formation in Renshou than in Chengdu City. In contrast, the proportion of secondary aerosols during the non-haze period in Chengdu City was significantly higher, indicating that direct emissions are still the main cause of air pollution in Chengdu City. PCA results showed that PM2.5 formation in both Chengdu City and Renshou County was mainly due to coal burning, vehicle operation, and biomass burning.

[Characterization of Tailpipe Emissions from in-use Excavators].

In this paper, the objective is to characterize real-world tailpipe emissions for excavators. Eight excavators in several construction sites in Chengdu were selected in this study. A portable emission measurement system (PEMS) was used for real-world emissions measurements (i. e., CO, HC, NO, and PM2.5) for three predefined operation modes:idling, moving, and working. The results showed that the tailpipe emissions of excavators vary depending on the operation mode as well as the equipment. NO emissions were relatively stable when the engine was idling compared to when the excavator was moving or doing actual work. In addition, excavators that complied to different emissions standards also exhibited different emissions, with those that met higher emission standards producing fewer emissions. For example, when comparing excavators complying with Stage Ⅱ emission standards to those complying with Stage Ⅰ emission standards, the NO and PM2.5 emissions appeared to decrease. On average, the NO emissions decreased by 8%, 35%, and 5%, and the PM2.5 emissions decreased by 88%, 87%, and 80% for the idling, moving, and working modes, respectively. Furthermore, the studies showed significant differences existed between the emissions factors in the real-world measurements and those recommended by national guidance. This indicated that real-world emission measurements of non-road equipment will play a key role in emissions inventory development. This study demonstrated that PEMS can be used to characterize real-world emissions from non-road equipment.

[Archaeal diversity associated with sponge Pachychalina sp. analyzed by culture-independent approach].

With culture-independent approach, microbial total DNA was directly extracted from Pachychalina sp. Using the total microbial DNA as template, archaeal 16S rDNAs were amplified by PCR with universal primers. Amplified products were cloned into T-vector and secondarily amplified by PCR. Then the secondarily amplified products were purified to be further characterized by termed ARDRA (amplified rDNA restriction analysis). According to the enzyme restriction mapping, the apparent difference among them were disclosed. Furthermore eight archaeal cloned partial sequences were acquired and built up a phylogenetic tree. In the phylogenetic tree, the eight archaea belonged to Methanogenium organophilum and Methanoplanus petrolearius, but the 16S rDNAs similarities among them and those archaea registered in RDP Database didn't excess to 90%. It means that they maybe represent some novel archaeal groups.