Global nitrogen (N) deposition has been enhanced with anthropogenic N emissions, and its impacts on mosses are receiving more and more attention. This study investigates how N deposition influence the biomass and stoichiometry of moss Rhytidium rugosum, using a 3-year N enrichment experiment with 0, 2, 5 and 10 g N m−2 yr−1 in a boreal forest in Northeast China. Low N additions caused an N redundancy and moderate to high N additions resulted in a biomass loss. N additions reduced biomass ratios of green to brown tissues and increased N and phosphorus (P) contents, suggesting changes in photosynthetic capacity and litter decomposition. Biomass N pools showed a unimodal response to the N additions, and P pools decreased under moderate and high N additions. Our findings indicate significant stoichiometric and biomass changes caused by N deposition may lead to a substantial carbon and nutrient loss in boreal moss carpets.

This study is the first comprehensive evaluation of total Hg and methylmercury (MeHg) concentrations in wild marine fish from an estuarine and a coastal ecosystem in southern China. A total of 571 fish from 54 different species were examined. Our results showed that the Hg levels were generally low in the fish, and the Hg levels were below 30 ng g−1 (wet weight) for 82% of the samples, which may be related to the reduced size of the fish and altered food web structure due to overfishing. Decreased coastal wetland coverage and different carbon sources may be responsible for the habitat-specific Hg concentrations. The degree of biomagnification was relatively low in the two systems.

Atmospheric PM10 were measured for 12 months at 18 sites along a 2500 km profile across northern China. Annual mean PM10 concentrations in urban, rural village, and rural field sites were 180 ± 171, 182 ± 154, and 128 ± 89 μg/m3, respectively. The similarities in PM10 concentrations between urban and rural village sites suggest that strong localized emissions and severe contamination in rural residential areas are derived from solid fuels combustion in households. High PM10 concentrations in Wuwei and Taiyuan were caused by either sandstorms or industrial activities. Relatively low PM10 concentrations were observed in coastal areas of Dalian and Yantai. Particulate air pollution was much higher in winter and spring than in summer and fall. Multiple regression analysis indicates that 35% of the total variance can be attributed to sandstorms, precipitation and residential energy consumption. Over 40% of the measurements in both urban and rural village areas exceeded the national ambient air quality standard.

Peroxy acetyl nitrate (PAN) is a key component of photochemical smog and plays an important role in atmospheric chemistry. Though it has been known that PAN is produced via reactions of nitrogen oxides (NOx) with some volatile organic compounds (VOCs), it is difficult to quantify the contributions of individual precursor species. Here we use an explicit photochemical model – Master Chemical Mechanism (MCM) model – to dissect PAN formation and identify principal precursors, by analyzing measurements made in Beijing in summer 2008. PAN production was sensitive to both NOx and VOCs. Isoprene was the predominant VOC precursor at suburb with biogenic impact, whilst anthropogenic hydrocarbons dominated at downtown. PAN production was attributable to a relatively small class of compounds including NOx, xylenes, trimethylbenzenes, trans/cis-2-butenes, toluene, and propene. MCM can advance understanding of PAN photochemistry to a species level, and provide more relevant recommendations for mitigating photochemical pollution in large cities.

The number and mass concentration, size distribution, and the concentration of 16 elements were studied in aerosol samples during the Spring Festival celebrations in 2013 in Beijing, China. Both the number and mass concentration increased sharply in a wide range from 10 nm to 10 μm during the firecrackers and fireworks activities. The prominent increase of the number concentration was in 50 nm–500 nm with a peak of 1.7 × 105/cm3 at 150 nm, which is 8 times higher than that after 1.5 h. The highest mass concentration was in 320–560 nm, which is 4 times higher than the control. K, Mg, Sr, Ba and Pb increased sharply during the firework activities in PM10. Although the aerosol emission from firework activities is a short-term air quality degradation event, there may be a substantial hazard arising from the chemical composition of the emitted particles.

In order to provide more conclusive evidence of monsoon-driven transport of persistent organic pollutants (POPs) to the Tibetan Plateau (TP) and assess the potential influence of forests on the fate of these pollutants, passive air samplers were consecutively deployed during 2008–2011 on Sygera Mountain (3800 m–4400 m). Higher DDTs levels were observed in the monsoon season (20.5–57.4 pg m−3) than the non-monsoon season (9.2–27.4 pg m−3), which confirmed that the Indian monsoon plays a key role in driving the atmospheric transport of DDTs to the TP. The similar DDT isomer ratios to the South Asia further suggested that Sygera Mountain is likely a receptor region of Indian subcontinent. By comparing the difference in concentrations between forest and clearing sites, it was found that the forest canopy can reduce airborne DDTs by a factor of 2, indicating strong absorption of DDTs by the Tibetan forest.

In vitro tests using human adenocarcinomic alveolar epithelial cell line A549 and small mouse monocyte-macrophage cell line J774A.1 were conducted to test toxicity of six PM (particulate matter) samples from Beijing. The properties of the samples differ significantly. The production of inflammatory cytokine (TNF-α for J774A.1) and chemokine (IL-8 for A549) and the level of intracellular reactive oxygen species (ROS) were used as endpoints. There was a positive correlation between water soluble organic carbon and DTT-based redox activity. Both cell types produced increased levels of inflammatory mediators and had higher level of intracelllar ROS, indicating the presence of PM-induced inflammatory response and oxidative stress, which were dose-dependent and significantly different among the samples. The releases of IL-8 from A549 and TNF-α from J774A.1 were significantly correlated to PM size, Zeta potential, endotoxin, major metals, and polycyclic aromatic hydrocarbons. No correlation between ROS and these properties was identified.

The bioavailability of Cu, Zn, Pb and Cd from field-aged orchard soils in a certified fruit plantation area of the Northeast Jiaodong Peninsula in China was assessed using bioassays with earthworms (Eisenia fetida) and chemical assays. Soil acidity increased with increasing fruit cultivation periods with a lowest pH of 4.34. Metals were enriched in topsoils after decades of horticultural cultivation, with highest concentrations of Cu (132 kg−1) and Zn (168 mg kg−1) in old apple orchards and Pb (73 mg kg−1) and Cd (0.57 mg kg−1) in vineyard soil. Earthworm tissue concentrations of Cu and Pb significantly correlated with 0.01 M CaCl2-extractable soil concentrations (R2 = 0.70, p < 0.001 for Cu; R2 = 0.58, p < 0.01 for Pb). Because of the increased bioavailability, regular monitoring of soil conditions in old orchards and vineyards is recommended, and soil metal guidelines need reevaluation to afford appropriate environmental protection under acidifying conditions.

Lead levels and isotopic compositions in atmospheric particles (TSP and PM2.5), street dust and surface soil collected from Nanjing, a mega city in China, were analyzed to investigate the contamination and the transfer of lead in urban environmental compartments. The lead contents in TSP and PM2.5 are significantly higher than them in the surface soil and street dust (p < 0.05). The enrichment factor using the mass ratio of lead to the major crustal elements (Al, Sr, Ti and Fe) indicates significant lead enrichment in atmospheric particles. The plots of 206Pb/207Pb vs.208Pb/206Pb and 206Pb/207Pb vs. 1/Pb imply that the street dust and atmospheric particles (TSP and PM2.5) have very similar lead sources. Coal emissions and smelting activities may be the important lead sources for street dust and atmospheric particles (TSP and PM2.5), while the deposition of airborne lead is an important lead source for urban surface soil.

Air pollution has been accepted as an important contributor to asthma development and exacerbation. However, the evidence is limited in China. In this study, we investigated the acute effect of air pollution on asthma hospitalization in Shanghai, China. We applied over-dispersed generalized additive model adjusted for weather conditions, day of the week, long-term and seasonal trends. An interquartile range increase in the moving average concentrations of PM10, SO2, NO2 and BC on the concurrent day and previous day corresponded to 1.82%, 6.41%, 8.26% and 6.62% increase of asthmatic hospitalization, respectively. The effects of SO2 and NO2 were robust after adjustment for PM10. The associations appeared to be more evident in the cool season than in the warm season. Our results contribute to the limited data in the scientific literature on acute effects of air pollution on asthma in high exposure settings, which are typical in developing countries.