[Concurrent Collection of Ammonia Gas and Aerosol Ammonium in Urban Beijing During National Celebration Days Utilizing an Acid-Coated Honeycomb Denuder in Combination with a Filter System].

Since 2013, the Chinese government implemented the Air Pollution Prevention and Control Action Plan. As a result, the atmospheric concentrations of sulfate reduced significantly, whereas the nitrate concentrations remain relatively high due to the excess of ammonia (NH3). To date, there is no official observation network monitoring NH3 concentrations in China. Previous studies have focused on NH3 or ammonium (NH4+) separately. These limitations hinder a complete understanding of their dynamic changes due to the rapid gas-to-particle conversion. In this study, the concentrations of NH3 and NH4+ were measured concurrently in urban Beijing during autumn 2019 utilizing an acid-coated denuder-filter combination with a time resolution from 2 h (PM2.5>35 µg·m-3) to 5 h (PM2.5<35 µg·m-3). The mean concentrations of NH3 and NH4+ during the study were (4.1±2.9)µg·m-3 and (1.7±1.4) µg·m-3, respectively. The temporal patterns of NH3 or NH4+ coincided with that of PM2.5, CO, and NO2 throughout the sampling period. The diurnal distributions of NH3 were bimodal, both on polluted (PM2.5>75 µg·m-3) and non-polluted (PM2.5<75 µg·m-3) days, peaking at 21:30-05:30 and 05:30-08:30, respectively. The NH3 concentrations on polluted days were relatively lower during 17:30-21:30, which may be related to higher wind speeds. In contrast to NH3, NH4+ had an obvious peak during 17:30-21:30 due to the formation of ammonium nitrate. The meteorological conditions favor the gas-to-particle conversion on polluted days, resulting in a lower NH3/NH4+ ratio of 0.8. However, this value may reach 2.8 on non-polluted days. The concentrations of NH3, CO, NO2, SO2, and PM2.5 in the emission control period showed a significant increase greater than or comparable to those in the non-control period by 54.2%, 40.4%, 33.3%, 0%, and 49.4%, respectively. This result shows that the stagnant conditions offset the benefit of emission control actions implemented during and before the National Celebration Day.

[Source Apportionment of Atmospheric Ammonia: Sensitivity Test Based on Stable Isotope Analysis in R Language].

Ammonia (NH3) is an important precursor of fine particles and nitrogen deposition. It is critical to identify and quantify the sources of NH3 before the implementation of a mitigation strategy. Stable isotope analysis in R (SIAR) has potential with regard to the source apportionment of NH3, but its reliability is closely related to the signatures (δ15N-NH3) of emission sources. Based on SIAR, we found that the agricultural contribution varied significantly with mean δ15N-NH3 values of endmember input. In contrast, both the contributions of fossil fuel and NH3 slip showed low sensitivity against the change of endmember input. Moreover, the agricultural contribution changed by about 20% due to the variations in agricultural endmember mean values. Such a change is five times that due to the variations in endmember standard deviation values. Notably, regardless of the number of input sources tested, "non-agricultural source" was the dominant source of NH3 during hazy days in January 2013 in Beijing. Since various agricultural sources showed large variations in δ15N-NH3, future studies should focus on the endmember signatures of agricultural sources to further reduce the uncertainty in SIAR-based NH3 source apportionment.

[Concurrent Measurement of Wet and Bulk Deposition of Trace Metals in Urban Beijing].

To characterize the dry and wet deposition of atmospheric trace elements in urban Beijing, both active and passive samplers were used to collect bulk and wet sedimentation samples between May 2014 and April 2015.The concentrations of 19 trace elements (Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Cu, Zn, As, Se, Mo, Cd, Sb, Tl, Th, and U) in the samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results show that the concentrations of metals in bulk deposition samples[7160.68 µg·L-1 (Ca)-0.02 µg·L-1 (Th)] were generally higher than those in wet deposition samples[4237.74 µg·L-1 (Ca)-0.01 µg·L-1 (Th)], but the enrichment factors of each metal in the two kinds of samples were less different. Of note, the enrichment factors of Cu, As, Tl, Zn, Cd, Se, and Sb were all larger than 100, thus indicating that these heavy metals were mainly from anthropogenic sources. The statistical analysis of the air mass trajectory shows that the precipitation chemistry in urban Beijing is mainly affected by southward air flows. The air mass originating from the southwest region always had higher concentrations of Ca, Mg, Fe, Al, Cu, Mo, U, and Th, whereas the air mass from the south had higher concentrations of K, Zn, Mn, Sb, Cd, and Tl. During the observation period, the bulk deposition fluxes of metals varied from 3591.35 mg·(m2·a)-1 (Ca)-0.01 mg·(m2·a)-1 (Th), and wet deposition fluxes varied from 1847.78 mg·(m2·a)-1 (Ca)-0.01 mg·(m2·a)-1 (Th). The dry deposition fluxes of the 19 metals varied from 1743.57 mg·(m2·a)-1 (Ca)-0.01 mg·(m2·a)-1 (Th). The particle size has important implications in the evaluation of the relative importance of dry deposition versus wet deposition during the scavenging of trace elements in air.

[Atmospheric Dry Deposition Fluxes and Seasonal Variations of Particulate Matter and Lead in Urban Beijing].

To investigate the dry deposition pattern of particulate matter and lead in urban Beijing, dry deposited particles were collected based on a surrogate surface between December 2013 and November 2014 and subjected to elemental analysis by using microwave digestion and inductively coupled plasma mass spectrometry. The results showed that dry deposition fluxes of particle mass and total lead were 0.84 t·(hm2·a)-1 and 7.56 mg·(m2·a)-1, respectively, with a seasonal trend of spring > winter > autumn~summer, exhibiting a similar temporal pattern to that of coarse particles. In addition, dry deposition flux of water-soluble lead was 3.14 mg·(m2·a)-1. It was found that the ratio of soluble fraction to total lead in dry deposited particles reached up to 43%, coinciding with a seasonal variation of ambient sulfur dioxide. The findings highlighted the anthropogenic imprints on the dry deposition flux of particles and heavy metals as well as the solubility of lead. This study also provides a first-hand dataset that can be used to assess ecological and environmental impacts of dry deposited lead, and an up-to-date scientific basis for the crafting abatement strategies to further reduce emission of heavy metals in China.

[Observations of Reactive Nitrogen and Sulfur Compounds During Haze Episodes Using a Denuder-based System].

Reactive nitrogen and sulfur compounds are chemically active in the atmosphere and play an important role in secondary particle formation. Among them, sulfate, nitrate, and ammonium (SNA) are important components of particulate matter (PM) that account for approximately one-third of fine particles. The precursors of SNA including HNO3, SO2, and NH3 are all involved in haze formation in China. To date, the concurrent measurements of SNA and their precursors have been limited to single sites and short terms because of the high cost of the instruments. This study aimed to use DELTA (Denuder for Long-Term Atmospheric sampling) to characterize the daily concentrations of reactive nitrogen and sulfur species during haze episodes. The results showed that the background interface of NH4+, NO3-, and SO42- in the denuder was minor and could be used to determine 24-48 h concentrations of NH3, HNO3, SO2, NH4+, and NO3-. However, the SO42- concentrations in the blank filter was so high that they could only be used for sampling weekly or for longer periods of time. During the campaign between May 9 and June 7, 2016 in urban Beijing, the concentrations of NH3, HNO3, NH4+, and NO3- showed distinct daily variations at different wind directions, i.e., higher values were observed during southerly winds and lower values during northerly winds. The time series of these reactive nitrogen compounds coincided with that of PM2.5, CO, SO2, and NO2, indicating the combustion of fossil fuels. The mean concentrations of NH3, HNO3, NH4+, and NO3- were twice the concentrations during clean days, further highlighting the effect of local emissions on the urban environment. The ratios of HNO3/NO3- and NH3/NH4+ were 1.2 and 4.5, respectively, without significant differences between hazy and clean days. The findings demonstrated that both the reduced and oxidized nitrogen were preferred in gaseous phase rather than particulate phase due to relatively high temperatures during the transition season of spring/summer.

[Magnetic property of dustfall in a Northwest China valley city and its environmental implications].

Lanzhou is one of the seriously polluted cities in Northwest China. Dustfall samples collected in Lanzhou and the countryside Huanghuatan were studied using magnetic methods. The results reveal that the content of magnetic mineral in dustfall samples from Lanzhou is much higher than that of Huanghuatan. At the same time, it has a much higher lever in winter than that of other seasons. The main magnetic minerals in the dustfall from both places are magnetite, maghemite and hematite, and the main magnetic grain sizes in dustfall samples are mainly pseudo single-domain(PSD) and multi-domain(MD). Although the air in Lanzhou is polluted seriously, the air quality has been improved greatly during the past decades and controlled well in recent years. Compared with other cities, air pollution in Lanzhou is affected significantly by urban terrain. This research also reveals that environmental magnetism has become a more and more important method in air pollution study.

[Characteristics of heavy metal elements and their relationship with magnetic properties of river sediment from urban area in Lanzhou].

The contents of As, Co, Cr, Cu, Ni, Pb, V and Zn in the surface sediments from 8 rivers in urban area in Lanzhou were monitored by ecological risk which was assessed by the potential ecological Håkanson index, and the index of geoaccumulation (Igeo), sediment enrichment factor (R), and environmental magnetism. The results showed that: (1) the potential ecological risk of heavy metals of As, Co, Ni, V in surface sediments from 8 rivers were low, which belonged to low ecological risk. But the risk of heave metals Cr, Pb, Zn in surface sediments from Yuer river was high, which belonged to middle ecological risk, and in downstream of Yuer river, the element of Cu belonged to high ecological risk. (2) The rivers in Lanzhou could be divided into four groups according to the heavy mental pollution degree: first type, such as Paihong river, Shier river, Yuer river and Shuimo river, called downstream concentrate type; second type, such as Qili river, called upstream concentrate type; third type, such as Luoguo river and Dasha river, called less affected type; fourth type, Lanni river, which polluted heavily in up and downstream; (3) The correlation analysis between magnetic parameters and element contents show that the parameters which mainly reflect the concentration of the magnetic minerals (X, SIRM, Ms) have close association with Cr, Ni, Pb, Zn, Cu, So we can infer that the magnetic minerals in deposits samples mainly came from electroplating effluent, motor vehicle emission, and domestic sewage. SIRM/X shows a strong correlation with Cr, Ni, Pb, Zn, indicating the distribution of anthropogenic particulates. (4) The magnetic minerals(X, SIRM, Ms) have a strong correlation with the geoaccumulation (Igeo) than potential ecological risk index and enrichment factor (R). These results suggest a possible approach for source identification of magnetic material in pollution studies and the validity of using magnetic measurements to mapping the polluted area.

[Magnetic characters of river sediment of urban area in Lanzhou].

A total of 23 deposits samples were collected from 8 selected the river sediments in Lanzhou urban area as researching objects of magnetic property and organic matter measure. The results indicate that: (1) the magnetic property controlled by magnetite which is ferrimagnetic mineral, and anti-ferromagnetic component such as hematite and goethite; (2) the value of samples' magnetic parameters (such as: chi, SIRM, magnetic hysteresis loops and M-T curves) increased from upstream to downstream in Paihong River, Shier River and Yuer River, Shuimo River; decreased in Qili River and Lanni River; and contrasting above-mentioned, the value of samples' magnetic parameters were low in Luoguo River and Dasha River. Based on the variation of magnetic parameters, such as chiFD, chiARM, chiFD/Ms and chiARM/Ms, we divided the rivers into three groups according to the contribution originating from anthropogenic activities into spatial river sediments: first type, such as Paihong River, Shier River, Yuer River and Shuimo River, called downstream concentrate type; second type, such as Qili River and Lanni River, called upstream concentrate type; third type, such as Luoguo River and Dasha River, called less affected type. Bulk samples also demonstrate a strong linear positive correlation between magnetic parameters chiFD, chiARM and the content of organic matter, which reflected the content of superparamagnetic and single domain grains were nice proxy parameters of the content of organic matter of river sediments.

Anatomic research and clinical application of modified penile elongation: a report of 205 cases / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the application of penile cavernous bodies elongation combined with fat flap for the treatment of micro-penis.</p><p><b>METHODS</b>Anatomic study was performed to study the thickness of penile suspension ligaments and the relationship between the penile erection stability and the mobilization of cavernous bodies crus. The suspension ligaments were divided and cavernous bodies crus were partially mobilized, so as to release part of the cavernous bodies from inferior ramus of pubis. Then the penis was elongated sufficiently. Local fat flap was transposed to fill the front space of pubis to make sure the effective elongation of penis.</p><p><b>RESULTS</b>205 cases of micro-penis were treated. The average length of the penis was 4.26 cm in the static state, 8.13 cm in erectile state before operation. After operation, it increased to 8.63 cm in the static state, 12.11 cm in erectile state.</p><p><b>CONCLUSIONS</b>The cavernous bodies can be elongated 1-2 cm more with the modified method, while the stability of penile erection is not affected.</p>