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[en] Vertical profiles of O_3 and SO_2 concentrations were monitored at the Borden Forest site in southern Ontario, Canada from May 2008 to April 2013. A modified gradient method (MGM) was applied to estimate O_3 and SO_2 dry deposition fluxes using concentration gradients between a level above and a level below the canopy top. The calculated five-year mean (median) dry deposition velocity (V_d) were 0.35 (0.27) and 0.59 (0.54) cm s"−"1, respectively, for O_3 and SO_2. V_d(O_3) exhibited large seasonal variations with the highest monthly mean of 0.68 cm s"−"1 in August and the lowest of 0.09 cm s"−"1 in February. In contrast, seasonal variations of V_d(SO_2) were smaller with monthly means ranging from 0.48 (May) to 0.81 cm s"−"1 (December). The different seasonal variations between O_3 and SO_2 were caused by the enhanced SO_2 uptake by snow surfaces in winter. Diurnal variations showed a peak value of V_d in early morning in summer months for both O_3 and SO_2. Canopy wetness increased the non-stomatal uptake of O_3 while decreasing the stomatal uptake. This also applied to SO_2, but additional factors such as surface acidity also played an important role on the overall uptake. - Highlights: • Application of a modified gradient-method for quantifying dry deposition is demonstrated. • A five-year dry deposition database is developed for O_3 and SO_2 over a mixed forest. • Canopy wetness enhances non-stomatal O_3 uptake while inhibits stomatal uptake. • High surface acidity reduces SO_2 dry deposition. - Capsule: A five-year dataset of O_3 and SO_2 dry deposition velocities was generated from concentration gradient measurement data using a modified gradient method.
[en] The performance of Cytisus striatus in association with different microbial inoculant treatments on the dissipation of the insecticide hexachlorocyclohexane (HCH) was studied. Two soils with different organic matter (A and B soil) content were spiked with 0 or 65 mg HCH kg−1. Plants were either not inoculated (NI), or inoculated with the endophyte Rhodococcus erythropolis ET54b and the HCH-degrader Sphingomonas sp. D4 separately or in combination (ET, D4 and ETD4). Unplanted pots were also established. HCH phytotoxicity was more pronounced in the B soil. Soil HCH concentrations in unplanted pots were similar to initial concentrations, whereas concentrations were reduced after plant growth: by 20% and 8% in A and B soil, respectively. Microbial inoculants also modified HCH dissipation, although effects were soil-dependent. Inoculation with the combination of strains (ETD4) led to a significant enhancement in HCH dissipation: up to 53% in the A soil and 43% in the B soil. -- Highlights: •Effect of microbial inoculants on HCH dissipation was studied in a plant-soil system. •Inoculation of C. striatus with bacterial strains strongly enhance HCH dissipation. •Retention of HCH by organic matter can influence efficiency of HCH phytoremediation. -- The inoculation of Cytisus striatus with a combination of bacterial strains is a promising approach for the remediation of HCH-contaminated sites
[en] A collection of 50 indigenous meta-toluate tolerating bacteria isolated from oil-contaminated rhizosphere of Galega orientalis on selective medium was characterized and identified by classical and molecular methods. 16S rDNA partial sequencing showed the presence of five major lineages of the Bacteria domain. Gram-positive Rhodococcus, Bacillus and Arthrobacter and gram-negative Pseudomonas were the most abundant genera. Only one-fifth of the strains that tolerated m-toluate also degraded m-toluate. The inoculum Pseudomonas putida PaW85 was not found in the rhizosphere samples. The ability to degrade m-toluate by the TOL plasmid was detected only in species of the genus Pseudomonas. However, a few Rhodococcus erythropolis strains were found which were able to degrade m-toluate. A new finding was that Pseudomonas migulae strains and a few P. oryzihabitans strains were able to grow on m-toluate and most likely contained the TOL plasmid. Because strain specific differences in degradation abilities were found for P. oryzihabitans, separation at the strain level was important. For strain specific separation (GTG)5 fingerprinting was the best method. A combination of the single locus ribotyping and the whole genomic fingerprinting techniques with the selective partial sequencing formed a practical molecular toolbox for studying genetic diversity of culturable bacteria in oil-contaminated rhizosphere. - Bacterial diversity during rhizoremediation in oil-contaminated soil is characterized by a combination of molecular methods
[en] China's strategies to control acidifying pollutants and particulate matter (PM) may be in conflict for soil acidification abatement. Acidifying pollutant emissions are estimated for 2005 and 2020 with anticipated control policies. PM emissions including base cations (BCs) are evaluated with two scenarios, a base case applying existing policy to 2020, and a control case including anticipated tightened measures. Depositions of sulfur (S), nitrogen (N) and BCs are simulated and their acidification risks are evaluated with critical load (CL). In 2005, the area exceeding CL covered 15.6% of mainland China, with total exceedance of 2.2 Mt S. These values decrease in the base scenario 2020, implying partial recovery from acidification. Under more realistic PM control, the respective estimates are 17.9% and 2.4 Mt S, indicating increased acidification risks due to abatement of acid-neutralizing BCs. China's anthropogenic PM abatement will have potentially stronger chemical implications for acidification than developed countries. - Highlights: → We model the emission and deposition of base cations and acid precursors in China. → Soil acidification in China is analyzed with exceedance of critical load. → China's PM control increases the acidification risk even with reduced SO2 emission. → The impact of PM for acidification is stronger than that in developed countries. - The control of anthropogenic PM emission in China will increase the risk of soil acidification even with reduced SO2 emission. Such implication is stronger than that in developed countries.
[en] This study provides the first estimate of dry deposition fluxes of criteria air pollutants (SO_2 and NO_x) across the Three Northern Regions Shelter Forest (TNRSF) region in Northern China and their long-term trends from 1982 to 2010 using the inferential method. Dry deposition velocities of SO_2 and NO_x increased in many places of the TNRSF up to 118.2% for SO_2 and 112.1% for NO_x over the last three decades due to the increased vegetation coverage over the TNRSF. The highest atmospheric deposition fluxes of SO_2 and NO_x were found in the Central-North China region, followed by the Northeast and the Northwest China regions of the TNRSF. A total of 820,000 t SO_2 and 218,000 t NO_x was estimated to be removed from the atmosphere through dry deposition process over the TNRSF from 1982 to 2010. About 50% of the total removal occurred in the Central-North China region. The estimated total SO_2 and NO_x dry deposition fluxes from 1982 to 2010 between a TNRSF site in this region and an adjacent farmland outside the TNRSF showed that the fluxes of these two chemicals at the TNRSF site were the factors of 2–3 greater than their fluxes in the farmland. - Highlights: • We investigate removal of air pollutants by the Three-North Shelter Forest (Green Great Wall) in China. • The trend of SO_2 and NO_x dry deposition velocity and flux over the TNRSF increase over the last three decades. • Increasing trends of deposition fluxes of SO_2 and NO_x are more evident in Central-North and Northeast China. • We show higher deposition fluxes of SO_2 and NO_x within the TNSF than outside TNRSF. • Stronger removal of air pollutants by the TNRSF is expected when other criteria air pollutants are taken into account. - The TNRSF is demonstrated to be an effective sink for SO_2 and NO_x and has increased the removal of air pollutants from Northern China.
[en] It is estimated that 49% of forests (17 million km2) will be exposed to damaging concentrations of tropospheric O3 by 2100. Global forest area at risk from S deposition may reach 5.9 million km2 by 2050, despite SO2 emission reductions of 48% in North America and 25% in Europe. Although SO2 levels have decreased, emissions of NOx are little changed, or have increased slightly. In some regions, the molar SO4/NO3 ratio in precipitation has switched from 2/1 to near 1/1 during the past two decades. Coincidentally, pattern shifts in precipitation and temperature are evident. A number of reports suggest that forests are being affected by air pollution. Yet, the extent to which such effects occur is uncertain, despite the efforts dedicated to monitoring forests. Routine monitoring programmes provide a huge amount of data. Yet in many cases, these data do not fit the conceptual and statistical requirements for detecting status and trends of forest health, nor for cause-effect research. There is a clear need for a re-thinking of monitoring strategies. - There is a need for reappraisal of monitoring methods used to assess air pollution effects on forest health
[en] The validity of using the Air Pollution Index (API) to assess health impacts of air pollution and potential modification by individual characteristics on air pollution effects remain uncertain. We applied distributed lag non-linear models (DLNMs) to assess associations of daily API, specific pollution indices for PM_1_0, SO_2, NO_2 and the weighted combined API (APIw) with mortality during 2003–2011 in Guangzhou, China. An increase of 10 in API was associated with a 0.88% (95% confidence interval (CI): 0.50, 1.27%) increase of non-accidental mortality at lag 0–2 days. Harvesting effects appeared after 2 days’ exposure. The effect estimate of API over lag 0–15 days was statistically significant and similar with those of pollutant-specific indices and APIw. Stronger associations between API and mortality were observed in the elderly, females and residents with low educational attainment. In conclusion, the API can be used to communicate health risks of air pollution. - Highlights: • The cumulative effects of API on mortality over lag 0–15 days remained significant. • The indices for three specific pollutants had similar associations with mortality. • The effects of API were modified by age, gender and educational attainment. • Our findings can help to communicate health risks of air pollution to the public. - The Air Pollution Index communicates health risks of air pollution
[en] As the atmospheric environment pollution has been becoming more and more serious in China, it is highly desirable to develop a scientific and effective early warning system that plays a great significant role in analyzing and monitoring air quality. However, establishing a robust early warning system for warning the public in advance and ameliorating air quality is not only an extremely challenging task but also a public concerned problem for human health. Most previous studies are focused on improving the prediction accuracy, which usually ignore the significance of uncertainty information and comprehensive evaluation concerning air pollutants. Therefore, in this paper a novel robust early warning system was successfully developed, which consists of three modules: evaluation module, forecasting module and characteristics estimating module. In this system, a new dynamic fuzzy synthetic evaluation is proposed and applied to determine air quality levels and primary pollutants, which can be regarded as the research objectives; Moreover, to further mine and analyze the characteristics of air pollutants, four different distribution functions and interval forecasting method are also employed that can not only provide predictive range, confidence level and the other uncertain information of the pollutants future values, but also assist decision-makers in reducing and controlling the emissions of atmospheric pollutants. Case studies utilizing hourly PM2.5, PM10 and SO2 data collected from Tianjin and Shanghai in China are applied as illustrative examples to estimate the effectiveness and efficiency of the proposed system. Experimental results obviously indicated that the developed novel early warning system is much suitable for analyzing and monitoring air pollution, which can also add a novel viable option for decision-makers. - Highlights: • A novel and robust air quality early warning system is developed in this paper. • Fuzzy synthetic evaluation is used to determine air quality and primary pollutants. • Interval prediction is applied to mine uncertainty information of air pollutants. • Proposed early warning system is great suitable for monitoring air quality.
[en] In order to better understand the spatial and temporal distribution pattern of metals and sulfur present in Shanghai, moss bags with Haplocladium microphyllum (Hedw.) Broth. were suspended at 14 local monitoring stations from April through June 2006 in Shanghai, the largest city in China. The results showed that the concentrations of S, Cu, Pb, and Zn in the moss bags after exposure were higher at the sites in the industrial district and most urban districts and lower at the sites in suburban areas, and well correlated with SO2 API and PM10 API in the air both in terms of space and time. The present study provided evidence that the moss H. microphyllum is suitable for bio-monitoring air pollution with moss bags and further confirmed that the moss-bag method is a simple, inexpensive and useful technique. - The moss Haplocladium microphyllum is suitable for bio-monitoring air pollution with moss bags
[en] Highlights: • The relationship between air pollution and respiratory disease is proposed. • Nonmalignant respiratory disease mortality was associated with PM10 and SO2. • Passive smokers are susceptible to the harmful effects of air pollution.