This research investigated the use of two relatively cost-effective devices for determining NH3 concentrations in naturally ventilated (NV) dairy barns including an Ogawa passive sampler (Ogawa) and a passive flux sampler (PFS). These samplers were deployed adjacent to sampling ports of a photoacoustic infrared multigas spectroscope (INNOVA), in a NV dairy barn. A 3-day deployment period was deemed suitable for both passive samplers. The correlations between concentrations determined with the passive samplers and the INNOVA were statistically significant (r = 0.93 for Ogawa and 0.88 for PFS). Compared with reference measurements, Ogawa overestimated NH3 concentrations in the barn by ∼14%, while PFS underestimated NH3 concentrations by ∼41%. Barn NH3 emission factors per animal unit (20.6–21.2 g d⁻¹ AU⁻¹) based on the two passive samplers, after calibration, were similar to those obtained with the reference method and were within the range of values reported in literature.

Following Europe and North America, East Asia has become a global hotspot for acid deposition, with very high deposition of both sulfur (S) and nitrogen (N) occurring in large areas of southwest and southeast China. This study shows that the outflow flux of sulfate (SO42−) in three major tributaries of the Upper Yangtze River in the Sichuan Basin in southwest China has been increasing over the last three decades, which implies the regional soil acidification caused by increasing sulfur dioxide (SO2) emissions. Since 2005, the outflow of SO42− to the Upper Yangtze River from the Sichuan Basin has even reached the atmospheric SO2 emission from the basin. In contrast to S emissions, the rapid increase in nitrogen (N) emissions, including nitrogen oxides (NOx) and ammonia (NH3), have resulted in only a slight increase in nitrate (NO3−) concentrations in surface waters, indicating a large retention of N in the basin. Although N deposition currently contributes much less than S to soil acidification in this area, it is possible that catchments receiving a high input of N may be unable to retain a large fraction of the N deposition over long periods.

Antibiotic mycelial fermentation residues (AMFRs), which are emerging solid pollutants, have been recognized as hazardous waste in China since 2008. Nitrogen (N), which is an environmental sensitivity element, is largely retained in AMFR samples derived from fermentation substrates. Pyrolysis is a promising technology for the treatment of solid waste. However, the outcomes of N element during the pyrolysis of AMFRs are still unknown. In this study, the conversion of N element during the pyrolysis of AMFRs was tracked using XPS (X-ray photoelectron spectroscopy) and online TG-FTIR-MS (Thermogravimetry-Fourier transform infrared-Mass spectrometry) technology. In the AMFR sample, organic amine-N, pyrrolic-N, protein-N, pyridinic-N, was the main N-containing species. XPS results indicated that pyrrolic-N and pyridinic-N were retained in the AMFR-derived pyrolysis char. More stable species, such as N-oxide and quaternary-N, were also produced in the char. TG-FTIR-MS results indicated that NH3 and HCN were the main gaseous species, and their contents were closely related to the contents of amine-N and protein-N, and pyrrolic-N and pyridinic-N of AMFRs, respectively. Increases in heating rate enhanced the amounts of NH3 and HCN, but had less of an effect on the degradation degree of AMFRs. N-containing organic compounds, including amine-N, nitrile-N and heterocyclic-N, were discerned from the AMFR pyrolysis process. Their release range was extended with increasing of heating rate and carbon content of AMFR sample. This work will help to take appropriate measure to reduce secondary pollution from the treatment of AMFRs.

The main aim of this study was to investigate the feasibility of using soybean meal added with papain to replace half of the fishmeal used in the moist pellets (49% fishmeal and 45% trash fish) developed by the Hong Kong Agriculture, Fisheries and Conservation Department (AFCD) for culturing marine fish. Gold-lined seabream (Rhabdosargus sarba), brown spotted grouper (Epinephelus bleekeri) and pompano (Trachinotus blochii) were farmed at one of the research stations (Kat-O) of AFCD, for a period of 340 days. Results indicated that diets containing papain resulted in better fish growth (reflected by relative weight gain and feed conversion ratio) than diets without papain. In general, wet weight gain of fish depends on the amount of papain added in diet rather than the diet composition. Soybean used in conjunction with papain also contributed to a more effective growth than fish fed with the moist pellets alone. A laboratory experiment (using tanks) was conducted to study the effects of the diets on concentrations of ammonia, nitrite and nitrate in the tank water. Results showed that concentrations of ammonia and nitrate were significantly lower (p < 0.05) when the fish were fed with papain-supplemented (with or without soybean meal) diets. It is envisaged that by using plant protein incorporated with enzymes could promote better growth of marine fish and lower the adverse impact of trash fish and fishmeal on water quality of the mariculture zones.

The quantification of atmospheric deposition flux is essential for assessment of its impact on ecosystems. We present an advanced approach for the estimation of the spatial pattern of atmospheric nitrogen deposition flux over the Czech forests, collating all available measured data and model results. The aim of the presented study is to provide an improved, more complete, more reliable and more realistic estimate of the spatial pattern of nitrogen deposition flux over one country. This has so far usually been based on measurements of ambient NOx concentrations as dry deposition proxy, and NH4+ and NO3− in precipitation as wet deposition proxy. For estimation of unmeasured species contributing to dry deposition, we used the CAMx Eulerian photochemical dispersion model, coupled with the Aladin regional numeric weather prediction model. The contribution of fog and dissolved organic nitrogen was estimated using a geostatistical data driven model. We prepared individual maps for particular components applying the most relevant approach and then merged all layers to obtain a final map representing the best estimate of nitrogen deposition over the Czech Republic. Final maps accounting for unmeasured species clearly indicate that the approach used so far may result in a substantial underestimation of nitrogen deposition flux. Our results showed that nitrogen deposition over the Czech forested area in 2008 was well above 2 g N m−2 yr−1, with almost 70% of forested area receiving 3–4 g N m−2 yr−1. NH3 and gaseous HNO3, contributing about 80%, dominated the dry nitrogen deposition. Estimating the unmeasured nitrogen species by modeled values provides realistic approximations of total nitrogen deposition that also result in more realistic spatial patterns that could be used as input for further studies of likely nitrogen impacts on ecosystems.

To assess pollution levels of major inorganic nitrogen species and their atmospheric deposition input to sensitive ecosystems in Sichuan Basin, southwest China, ambient concentrations of oxidized (NOy ∼ NO2, HNO3, NO3−) and reduced (NHx = NH3, NH4+) nitrogen species were collected at two urban sites during four one-month periods, each in a different season from July 2014 to April 2015. Estimated annual mean concentration of NOy was 20.3 and 13.5 μg N m−3 in Chengdu and Wanzhou, respectively, and NHx was 16.9 and 13.6 μg N m−3, respectively. Back trajectory cluster analysis indicated that high levels of NOy and NHx in Chengdu were mainly caused by local emissions while those in Wanzhou were caused by both the local emissions and long-range transport of pollutants. On annual basis, NO2 contributed the most to NOy, followed by NO3− and HNO3, accounting for 87.5%, 10.5% and 2.0%, respectively, of NOy in Chengdu, and 91.4%, 6.9% and 1.7%, respectively, in Wanzhou. NH3 was the predominant contributor to NHx, contributing 65.6% and 72.2% in Chengdu and Wanzhou, respectively. Dry deposition fluxes were estimated using the inferential method with measured ambient concentrations and modelled dry deposition velocities. The total inorganic nitrogen dry deposition flux was estimated to be 21.4 and 8.5 kg N ha−1 yr−1, with 44.3% and 41.4% from NOy in Chengdu and Wanzhou, respectively. NO2 and NH3 each contributed about 80% of NOy and NHx dry deposition, respectively. Wet deposition was only collected in Wanzhou, where the annual wet deposition of NO3− and NH4+ was 4.5 and 15.7 kg N ha−1 yr−1, respectively. The total wet plus dry deposition was 28.7 kg N ha−1 yr−1 in Wanzhou with 72.2% from reduced nitrogen. Therefore, controlling NH3 emissions from agricultural, traffic, waste containers and sewage system sources would be effective to reduce the total nitrogen deposition in the Sichuan Basin area.

Atlantic old sessile oak woodlands are of high conservation importance in Europe, listed in the European Union (EU) Habitats Directive Annex I, and known for their rich bryophyte communities. Their conservation status ranges from unfavourable to bad across their known distribution, which is predominantly within the UK and Ireland, but also extends into Iberia and Brittany. The objectives of this study were to determine if nitrogen (N) deposition, a known driver of terrestrial biodiversity loss, was a significant predictor of community composition in old sessile oak woodlands (i.e., EU Habitats Directive Annex I class: 91A0), and to identify significant changes in individual plant species and community-level abundance (i.e., change points) along an N deposition gradient. Relevé data from 260 Irish oak woodland plots were evaluated using Canonical Correspondence Analysis (CCA) and Threshold Indicator Taxa ANalysis (TITAN). Nitrogen deposition accounted for 14% of the explainable variation in the dataset (inertia = 0.069, p < 0.005). A community scale change point of 13.2 kg N ha−1 yr−1 was indicated by TITAN, which falls within the current recommended critical load (CL) range for acidophilous Quercus-dominated (oak) woodlands (10–15 kg N ha−1 yr−1). The results suggest that the current CL is sufficient for maintaining a core group of indicator species in old sessile oak woodlands, but many nutrient sensitive species may disappear even at the CL range minimum.

Enforcement of an air quality standard for PM2.5 in the Seoul metropolitan area (SMA) was enacted in 2015. From May to June of 2016, an international airborne and surface measurement campaign took place to investigate air pollution mechanisms in the SMA. The total and speciated PM2.5 concentrations since 2008 have been measured at an intensive monitoring site for the SMA operated by the National Institute of Environmental Research (NIER). To gain insight on the trends and sources of PM2.5 in the SMA in May, we analyze PM2.5 concentrations from 2009 to 2013 using the measurements and simulations from a 3-dimensional global chemical transport model, GEOS-Chem and its adjoint. The model is updated here with the latest regional emission inventory and diurnally varying NH3 emissions. Monthly average PM2.5 concentration measured by β-ray attenuation ranges from 28 (2010) to 45 (2013) μg/m3, decreased from 2009 to 2010, and then continuously increased until 2013. The model shows good agreement with the measurements for the daily average PM2.5 concentrations (R ≥ 0.5), and reproduces 10 out of 17 measured episodes exceeding the daily air quality standard (50 μg/m3). Using the GEOS-Chem adjoint model, we find that anthropogenic emissions from the Shandong region have the largest modeled influence on PM2.5 in Seoul in May. Average contributions to the high PM2.5 episodes simulated by the model are 39% from the Shandong region, 16% from the Shanghai region, 14% from the Beijing region, and 15% from South Korea. Anthropogenic SO2 emissions from South Korea are negligible with 90% of the total contribution originating from China. Findings from this study may guide interpretation of observations obtained in the KORUS-AQ measurement campaign.

Few studies have been carried out so far for measuring concentrations of NH3, NO2 and O3 in plastic greenhouses. In this study, NH3, NO2 and O3 concentrations were measured with passive sampler technology in a plastic greenhouse located in the Changsha suburb in southern China over a one and a half month period (November 30, 2008 to January 11, 2009). Soil in the greenhouse was subjected to four treatment (T) types (no N fertilizer T1, common urea T2, coated urea T3 and common urea with nitrification inhibitor dicyandiamide (DCD) T4. The average concentrations (μg/m3) of NH3, NO2 and O3 in descending order was: T4 (31.66) > T2 (25.93) > T3 (23.52) > T1 (7.96), T2 (10.99) > T3 (8.16) > T4 (7.48) > T1 (5.20), T2 (75.05) > T3 (64.20) > T4 (63.85) > T1 (49.02), respectively. This implied that photochemical reactions took place and that harmful gases accumulated after application of N fertilizer in the plastic greenhouse. DCD inhibited the conversion of ammonium to nitrate, increased NH3 volatilization and decreased NO2 level. The coated urea decreased the emissions of NH3 and increased nitrogen use efficiency. We found significant positive correlations (p < 0.01) between temperature and both NH3 and NO2 levels. Correlations between soil pH and both NH3 and NO2 concentrations were also significant (p < 0.01). The O3 average concentration from March 31, 2009 to April 10, 2009 in the higher latitude of the Yinchuan suburb in northern China was two times greater than that in the Changsha suburb in southern China. The O3 daily concentrations in the Yinchuan suburb exceeded 160 μg/m3 (i.e., China's Grade I standard), and the maximal value 214.83 μg/m3 exceeded 200 μg/m3 (i.e., China's Grade III standard).

The Arctic atmosphere has been disturbed by human activities. To improve the understanding of anthropogenic influences, major ionic species and carbonaceous components were measured at Ny-Ålesund in July 2012. The results suggested that Na+ and Cl− are the dominant water soluble inorganic species, accounting for 57 ± 17% of the mass of measured ionic species, and 61% of the variance in organic carbon can be explained by oceanic emissions. Aerosols in this area were found to be altered by secondary production involving oxides of sulfur, nitrogen and ammonia from anthropogenic activities, resulting in relative high concentrations of secondary inorganic aerosols (SIA) (such as non-sea salt (nss)-SO42−, NO3− and NH4+), with a mean concentration of 158 ng m−3. SIAs were featured by a mean [NH4+]/[nss-SO42−] ratio of 0.57 and a neutralization ratio (NR) of 0.074, indicating a deficit of NH4+. Thus, the production of particulate NH4 NO3 was strongly limited and SIAs were likely to remain in more acidic forms, NH4HSO4 or H2SO4 rather than as (NH4)2SO4. Chloride depletion of 11%–22% occurred in the samples with high concentrations of excess acidic species (defined as [nss-SO42− + NO3− − NH4+]) and high sea salts. The formation of SIAs and chloride depletion appeared to produce acidic aerosols with a mean pH of 4.51 and high free [H] concentrations of 3.06 ± 0.75 nmol m−3 in aerosols, accounting for 77% of the total [H] concentration. This implies that anthropogenic species could be engaged efficiently in modifying of the properties of aerosols at Ny-Ålesund.