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Aerosol iron (Fe) solubility is a key factor for the assessment of atmospheric nutrients input to the ocean but poorly specified in models because the mechanism of determining the solubility is unclear. We develop a deep learning model to project the solubility based on the data that we observed in a coastal city of China. The model has five variables: the size range of particles, relative humidity, and the ratios of sulfate, nitrate and oxalate to total Fe (TFe) contents in aerosol particles. Results show excellent statistical agreements with the solubility in the literature over most worldwide seas and margin areas with the Pearson correlation coefficients (

Alkaline gases such as NH3 and amines play important roles in neutralizing acidic particles in the atmosphere. Here, two common gaseous amines (dimethylamine (DMA) and trimethylamine (TMA)), NH3, and their corresponding ions in PM2.5 were measured semicontinuously using an ambient ion monitor-ion chromatography (AIM-IC) system in marine air during a round-trip cruise of approximately 4000 km along the coastline of eastern China. The concentrations of particulate DMA, detected as DMAH+, varied from

Microbial infection and the limitation of tissue regeneration are main obstacles to chronic wound healing. Herein, a biofunctional hydrogel is prepared to simultaneously kill bacteria efficiently and promote would healing. First, a rose bengal/polypyrrole hybrid poly(vinyl alcohol) hydrogel (RB/PPy PVA HD) is synthesized and its antibacterial property is investigated under coirradiation of 550 nm visible light and 808 near-infrared light. The hydrogel exhibits excellent antibacterial activity within 10 min below 45 °C in vitro due to the synergistic effect of photothermal and photodynamic antibacterial therapy. Next, the recombined human epidermal growth factor (rhEGF) is physically absorbed on the surface of the porous hydrogel to form a RB/PPy/rhEGF hybrid PVA HD (rhEGF/RB/PPy PVA HD). The introduction of rhEGF enables the hydrogel to promote fibroblast proliferation and collagen secretion. Furthermore, the in vivo results indicate that the rhEGF/RB/PPy PVA HD can control infection effectively and promote wound healing significantly.

Nonthermal plasma (NTP)-enhanced CO catalytic oxidation over CuOx@γ-Al2O3 was investigated in a coaxial dielectric barrier discharge reactor at ambient temperature under dry and humid conditions. T...

To assess the relative contributions of traffic emission and other potential sources to high levels of atmospheric ammonia (NH3) in urban areas in the wintertime, atmospheric NH3 and related pollutants were measured at an urban site, ∼300 m from a major traffic road, in northern China in November and December 2015. Hourly average NH3 varied from 0.3 to 10.8 ppb with an average of 2.4 ppb during the campaign. Contrary to the common perspective in literature, traffic emission was demonstrated to be a negligible contributor to atmospheric NH3. Atmospheric NH3 correlated well with ambient water vapor during many time periods lasting from tens of hours to several days, implying NH3 released from water evaporation is an important source. Emissions from local green space inside the urban areas were identified to significantly contribute to the observed atmospheric NH3 during ∼60% of the sampling times. Evaporation of predeposited NHx through wet precipitation combined with emissions from local green space likely...

Particles larger than 50-100 nm in diameter have been considered to be effective cloud condensation nuclei (CCN) under typical atmospheric conditions. We studied the growth of newly formed particles (NPs) in the atmosphere and the conditions for these particles to grow beyond 50 nm at a suburban coastal site in Hong Kong. Altogether, 17 new particle formation events each lasting over 1 h were observed in 17 days during 8 Mar-28 Apr and 1 Nov-30 Dec 2011. In 12 events, single-stage growth of NPs was observed in daytime when the median mobility diameter of NPs (Dp) increased up to ∼40 nm but did not increase further. In three events, two-stage particle growth to 61-97 nm was observed at nighttime. The second stage growth was preceded by a first-stage growth in daytime when the Dp reached 43 ± 4 nm. In all these 15 events, organics and sulfuric acid were major contributors to the first-stage growth in daytime. Ammonium nitrate unlikely contributed to the growth in daytime, but it was correlated with the second-stage growth of ∼40 nm NPs to CCN sizes at nighttime. The remaining two events apparently showed second-stage growth in late afternoon but were confirmed to be due to mixing of NPs with pre-existing particles. We conclude that daytime NP growth cannot reach CCN sizes at our site, but nighttime NP growth driven by organics and NH4NO3 can.

Sampling artifact of chloride depletion from collected sea salt particles was studied, based on simultaneous measurements of size distribution measurements by a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI) and of PM2.5 measurements by a Compact Porous Metal Denuder Sampler (PMDS) at a coastal site in Hong Kong on May 7, 8, 9, 11, and 29, 1998. The ambient concentrations of SO2, HNO3, HNO2, and NH3 were also measured by the PMDS. PM2.5 measurements by the PMDS, which is equipped with denuders and nylon back filters, are compared with the PM1.8 and PM3.1 measurements by the MOUDI. The percentages of chloride depletion from sea salt aerosols in PM1.8 and PM3.1 were 4-45% higher than that in PM2.5. This suggests that chloride evaporation in PM1.8 and PM3.1 collected on Teflon filters of the MOUDI during sampling was present. From the sum of the contributions of particles on the Teflon and nylon filters of the PMDS, nitrate formation almost completely accounts for chloride depletion in PM2.5 prior to collection since the equivalent ratio of [Na+] to ([NO3-] + [Cl-]) is close to the seawater ratio of 0.85. However, it was found that 22-74% of nitrate and 45-86% of chloride in the collected particles on the Teflon filter of the PMDS evaporated during sampling. Excess chloride depletion unexplained by NO3- and nss-SO4(2-) was found in the collected particles on the Teflon filter of the PMDS. Similarly, an amount of 3.7-27.2 nequiv m-3 of excess depleted chloride (equivalent to 8-55% of total chloride depletion) was found in supermicron particles collected by the MOUDI. In the 1.8-3.1 microns particles, the excess depleted chloride is positively correlated to the chloride evaporated from the deposited particles. Particle--particle interactions are proposed to explain the evaporation of nitrates and chlorides in the PMDS and MOUDI measurements. The observed chloride depletion from seasalt aerosols was partially attributed to sampling artifact due to particle--particle interactions.