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1.
Strict air pollution control measures were conducted during the Youth Olympic Games(YOG) period at Nanjing city and surrounding areas in August 2014.This event provides a unique chance to evaluate the effect of government control measures on regional atmospheric pollution and greenhouse gas emissions.Many previous studies have observed significant reductions of atmospheric pollution species and improvement in air quality,while no study has quantified its synergism on anthropogenic CO2...  相似文献   

2.
Aeolian dust particles arising from arid and semiarid zones are known to carry microbes by air currents. The effect of wind-borne bacteria on atmospheric bacterial population at various downwind distances from the dust source regions must be clarified, but has not yet been reported. This study monitored the bacterial abundance and community composition in outdoor aerosol samples in Beijing, China, which is close to the Asian dust source regions, and compared them with the results obtained in a distant region(Osaka, Japan).The Asian dust collected in Beijing contained(4 ± 3) × 10~4 bacterial cells/m~3, approximately~4 times higher than in Osaka. On 15 April 2015, Beijing experienced severe Asian dust events with a 1000-fold increase in bacterial abundance, relative to non-Asian dust days. Dominant bacterial phyla and classes in Asian dust collected in Beijing were Actinobacteria, Bacilli and Acidobacteria, and the bacterial community composition varied more widely than in Osaka.The bacterial community compositions differed between the Beijing and Osaka dusts, even for the same Asian dust events. These results indicated that aerosol bacterial communities nearer the dust source are more affected by eolian dust than their distant counterparts.  相似文献   

3.
Indoor air quality (IAQ) directly affects the health of occupants. Household manufacturing equipment (HME) used for hobbies or educational purposes is a new and unexplored source of air pollution. In this study, we evaluated the characteristics of particulate and gaseous pollutants produced by a household laser processing equipment (HLPE). Various target materials were tested using a commercial HLPE under various operating conditions of laser power and sheath air flow rate. The mode diameters of the emitted particles gradually decreased as laser power increased, while the particle number concentration (PNC) and particle emission rate (PER) increased. In addition, as the sheath air flow rate quadrupled from 10 to 40 L/min, the mode diameter of the emitted particles decreased by nearly 25%, but the effect on the PNC was insignificant. When the laser induced the target materials at 53 mW, the mode diameters of particles were <150 nm, and PNCs were >2.0 × 104 particles/cm3. Particularly, analyses of sampled aerosols indicated that harmful substances such as sulfur and barium were present in particles emitted from leather. The carcinogenic gaseous pollutants such as acrylonitrile, acetaldehyde, 1,3-butadiene, benzene, and C8 aromatics (ethylbenzene) were emitted from all target materials. In an actual indoor environment, the PNC of inhalable ultrafine particles (UFPs) was >5 × 104 particles/cm3 during 30 min of HLPE operation. Our results suggest that more meticulous control methods are needed, including the use of less harmful target materials along with filters or adsorbents that prevent emission of pollutants.  相似文献   

4.
Previous studies on environmental antibiotics resistance genes(ARGs) have focused on the pollution sources such as wastewater treatment plants, aquaculture and livestock farms,etc. Few of them had addressed this issue in a regional scale such as river catchment. Hence,the occurrence and abundances of 23 ARGs were investigated in surface water samples collected from 38 sites which located from the river source to estuary of the Beijiang River.Among them, 11 ARGs were frequently detected in this region and 5 ARGs(sul I, sul II, tet B,tet C, and tet W) were selected for their distribution pattern analysis. The abundances of the selected ARGs were higher in the upstream(8.70 × 10~6 copies/ng DNA) and downstream areas(3.17 × 10~6 copies/ng DNA) than those in the midstream areas(1.23 × 10~6 copies/ng DNA), which was positively correlated to the population density and number of pollution sources. Pollution sources of ARGs along the Beijiang River not only had a great impact on the abundances and diversity, but also on the distribution of specific ARGs in the water samples. Both sul I and sul II were likely originated from aquaculture farms and animal farms,tet W gene was possibly associated with the mining/metal melting industry and the electric waste disposal and tet C gene was commonly found in the area with multiple pollution sources.However, the abundance of tet B was not particularly related to anthropogenic impacts. These findings highlight the influence of pollution sources and density of population on the distribution and dissemination of ARGs at a regional scale.  相似文献   

5.
Tropospheric ozone(O_3) is a major air pollutant and causes serious injury to vegetation. To protect sensitive plants from O_3 damage, several agrochemicals have been assessed,including cytokinin(e.g., kinetin, KIN) and ethylenediurea(EDU) with cytokinin-like activity.In higher plant, leaves are primarily injured by O_3 and protective agrochemicals are often applied by leaf spraying. To our knowledge, the mitigating abilities of EDU and KIN have not been compared directly in a realistic setup. In the present research, impacts of elevated O3(2 × ambient O_3, 24 hr per day, for 8 days) on an O_3 sensitive line(S156) of snap bean(Phaseolus vulgaris), which is often used for biomonitoring O_3 pollution, were studied in a free air controlled exposure system. The day before starting the O_3 exposure, plants were sprayed with a solution of EDU(300 ppm), KIN(1 mmol/L) or distilled water, to compare their protective abilities. The results demonstrated that 2 × ambient O_3 inhibited net photosynthetic rate and stomatal conductance, increased the minimal fluorescence yield of the dark-adapted state, decreased the maximal quantum yield of PSII photochemistry, and led to visible injury. KIN and EDU alleviated the reduction of the photosynthetic performance, and visible injury under O_3 fumigation. The plants sprayed with EDU showed greater ability to mitigate the O_3 damage than those sprayed with KIN. Chlorophyll fluorescence imaging may have detected more precisely the differences in O_3 response across the leaf than the conventional fluorometer.  相似文献   

6.
7.
This paper describes the results of combining several simple models to assess the changes in plant sensitivity to direct effects of gaseous air pollutants that result from changes in climatic conditions. This research has been carried out within the framework of a project on the integrated assessment of regional air pollution and climate change in Europe (AIR-CLIM). The modulation of plant sensitivity to gaseous pollutants has been studied using a model of stomatal conductance that simulates the flow of water vapor from the atmosphere to the plant interior through the stomata. The model has been applied to Norway spruce (Picea abies L.) and European beech (Fagus sylvatica L.). The critical atmospheric concentration levels for SO2 and NOx adopted in international environmental norms have been modified to maintain in different climate scenarios a concentration level inside the plant equivalent to the critical limit in 1990. These simulated critical concentrations are compared with the predicted atmospheric concentrations. Our work indicates that the response can be very different for the two types of forests and in different regions. In general, climate change sensitivity increases in boreal areas and decreases in temperate areas due to temperature and water stress. If the air pollution levels are in the predicted ranges, the problems are less severe now than in 1990, but the cumulative stress will still be significant.  相似文献   

8.
The aim of this study was to evaluate the potential role of office fomites in respiratory (human parainfluenza virus 1—HPIV1, human parainfluenza virus 3—HPIV3) and enteric (norovirus GI—NoV GI, norovirus GII—NoV GII) viruses transmission by assessing the occurrence of these viruses on surfaces in office buildings. Between 2016 and 2017, a total of 130 surfaces from open-space and non-open-space rooms in office buildings located in one city were evaluated for HPIV1, HPIV3, NoV GI, and NoV GII viral RNA presence. Detection of viruses was performed by RT-qPCR method. Study revealed 27 positive samples, among them 59.3% were HPIV3-positive, 25.9% HPIV1-positive, and 14.8% NoV GII-positive. All tested surfaces were NoV GI-negative. Statistical analysis of obtained data showed that the surfaces of office equipment including computer keyboards and mice, telephones, and desktops were significantly more contaminated with respiratory viruses than the surfaces of building equipment elements such as door handles, light switches, or ventilation tracts (χ 2 p = 0.006; Fisher’s Exact p = 0.004). All examined surfaces were significantly more contaminated with HPIVs than NoVs (χ 2 p = 0.002; Fisher’s Exact p = 0.003). Office fomites in open-space rooms were more often contaminated with HPIVs than with NoVs (χ 2 p = 0.016; Fisher’s Exact p = 0.013). The highest average concentration of HPIVs RNA copies was observed on telephones (1.66 × 102 copies/100 cm2), while NoVs on the light switches (1.40 × 102 copies/100 cm2). However, the Kruskal–Wallis test did not show statistically significant differences in concentration levels of viral RNA copies on surfaces between the all tested samples. This study unequivocally showed that individuals in office environment may have contact with both respiratory and enteric viral particles present on frequently touched surfaces.  相似文献   

9.
The aim of this study was to assess the viral contamination of group A rotavirus (RVA), norovirus (NoV), and human astrovirus (HAstV) in sewage directly discharged into Uruguay River and to characterize RVA genotypes circulating in Uruguay. For this purpose, sewage samples (n = 96) were collected biweekly from March 2011 to February 2012 in four Uruguayan cities: Bella Unión, Salto, Paysandú, and Fray Bentos. Each sample was concentrated by ultracentrifugation method. Qualitative and quantitative RT-PCR for RVA, NoV, and HAstV were performed. A wide dissemination of gastroenteric viruses was observed in the sewage samples analyzed with 80 % of positivity, being NoV (51 %) the most frequently detected followed by RVA with a frequency of 49 % and HAstV with 45 %. Genotypes of RVA were typed using multiplex semi-nested RT-PCR as follows: P[8] (n = 15), P[4] (n = 8), P[10] (n = 1), P[11] (n = 1), G2 (n = 29), and G3 (n = 2). The viral load ranged from 103 to 107 genomic copies/liter, and they were detected roughly with the same frequency in all participant cities. A peak of RVA and HAstV detection was observed in colder months (June to September), whereas no seasonality was observed for NoV. This study demonstrates for the first time, the high degree of gastroenteric viral contamination in the country; highlighting the importance of developing these analyses as a tool to determine the viral contamination in this hydrographic boundary region used by the local populations for recreation and consumption, establishing an elevated risk of gastroenteric diseases for human health.  相似文献   

10.
长三角地区火电行业主要大气污染物排放估算   总被引:6,自引:3,他引:3  
丁青青  魏伟  沈群  孙予罕 《环境科学》2015,36(7):2389-2394
以2012年为基准年,利用排放因子法估算了长三角地区火电行业主要大气污染物(SO2、NOx、烟尘、PM10、PM2.5)排放.其中,SO2、NOx、烟尘、PM10、PM2.5的排放量分别为473 238、1 566 195、587 713、348 773、179 820 t.对于SO2和NOx,300 MW以上机组的贡献分别为85%和82%;烟尘、PM10和PM2.5方面,100 MW以下的机组贡献占比分别为81%、53%和40%.地区贡献方面,由大到小依次为江苏、浙江和上海.另通过对上海地区多家电厂不同等级机组污染排放数据进行统计计算,得出上海地区300 MW以上等级机组的污染物排放因子,对比分析可知,上海地区火电厂污染物排放因子水平总体较低.假设长三角地区火电行业同等级机组均与现在上海地区机组排放水平相当,则行业排放SO2可削减55.8%~65.3%,NOx可以削减50.5%~64.1%,烟尘可以削减3.4%~11.3%.若能提高较小等级机组的发电技术和污染控制水平,各污染物排放削减量可进一步提高.然而,根据长三角地区实际污染情况,应综合因素考虑火电行业削减排放,以促进区域空气质量不断改善.  相似文献   

11.
A three-year sampling campaign was conducted at a roadside air pollution monitoring station in the urban area of Kanazawa, Japan. Due to a new emission regulation, PAHs levels decreased over the sampling campaign, exhibiting values of 706 ± 413 pg/m3 in 2017, 559 ± 384 pg/m3 in 2018, and 473 ± 234 pg/m3 in 2019. In each year, similar seasonal variations in PAHs levels were observed, with higher levels observed in winter and lower levels in summer. Among the PAHs isomer ratios, we observed that the ratio of benzo[b]fluoranthene (BbF) and benzo[k]fluoranthene (BkF), [BbF]/([BbF] + [BkF]), and the ratio of indeno[1,2,3-cd]pyrene (IDP) and benzo[ghi]perylene (BgPe), [IDP]/([BgPe] + [IDP]), showed stability over the sampling campaign and were less affected by the new emission regulation, seasonal variations, and regional characteristics. When using the combined ratio ranges of 0.66 - 0.80 ([BbF]/([BbF] + [BkF]) and 0.26-0.49 ([IDP]/([BgPe] + [IDP]), traffic emissions were clearly distinguished from other PAHs emission sources. Principal component analysis (PCA) and positive matrix factorization (PMF) were also performed to further analyse the characteristics of traffic-related PAHs. Overall, this study affirmed the effectiveness of the new emission regulation in the reduction of PAHs emissions and provided a combined range for identifying PAHs traffic emission sources.  相似文献   

12.
Ultraviolet (UV)/monochloramine (NH2Cl) as an advanced oxidation process was firstly applied for Aspergillus spores inactivation. This study aims to: i) clarify the inactivation and photoreactivation characteristics of UV/NH2Cl process, ii) compared with UV/Cl2 in inactivation efficiency, photoreactivation and energy consumption. The results illustrated that UV/NH2Cl showed better inactivation efficiency than that of UV alone and UV/Cl2, and could effectively control the photoreactivation. For instance, the inactivation rates for Aspergillus flavus, Aspergillus niger and Aspergillus fumigatus in the processes of UV/NH2Cl (2.0 mg/L) was 0.034, 0.030 and 0.061 cm2/mJ, respectively, which were higher than that of UV alone (0.027, 0.026 and 0.024 cm2/mJ) and UV/Cl2 (0.023, 0.026 and 0.031 cm2/mJ). However, there was no synergistic effect for Aspergillus flavus and Aspergillus fumigatus. As for Aspergillus niger, the best synergistic effect can reach 1.86-log10. This may be due to their different resistance to disinfectants, which were related to the size, an outer layer of rodlets (hydrophobins) and pigments. After UV/NH2Cl inactivation, the degree of cell membrane damage and intracellular reactive oxygen species were higher than that of UV alone. UV/NH2Cl had the advantages of high inactivation efficiency and inhibition of photoreactivation, which provides a new entry point for the disinfection of waterborne fungi.  相似文献   

13.
Nitrogen dioxide (NO2) is one of the most common and harmful air pollutants. To analyze the response of plants to NO2 stress, we investigated the morphological change, reactive oxygen species (ROS) production and antioxidant enzyme activity in Arabidopsis thaliana (Col-0) exposed to 1.7, 4, 8.5, and 18.8 mg/m3 NO2. The results indicate that NO2 exposure affected plant growth and chlorophyll (Chl) content, and increased oxygen free radical (O2) production rate in Arabidopsis shoots. Furthermore, NO2 elevated the levels of lipid peroxidation and protein oxidation, accompanied by the induction of antioxidant enzyme activities and change of ascorbate (AsA) and glutathione (GSH) contents. Following this, we mimicked nitric acid mist under experimental conditions, and confirmed the antioxidant mechanism of the plant to the stress. Our results imply that NO2 and its acid mist caused pollution risk to plant systems. During the process, increased ROS acted as a signal to induce a defense response, and antioxidant status played an important role in plant protection against NO2/nitric acid mist-caused oxidative damage.  相似文献   

14.
Pollen pollution and allergy are becoming prominent issues in China. However, few studies on pollinosis have been reported. As an allergen in the atmosphere, allergenic Humulus scandens pollen was collected from four districts of Shanghai, including Wusong (WS), Jiading (JD), Xujiahui (XJH) and Songjiang (SJ). The mass concentrations of SO2, NO2, O3, PM10, and PM2.5 (particulate matter with air dynamic diameter less than 10 and 2.5 µm, respectively) near the four sampling sites were also recorded during Humulus scandens pollen season. The allergenicity of the Humulus scandens pollen was assessed by using of a rat model and enzyme linked immunosorbent assay (ELISA). Relationships between the allergenicity and air pollutants were correlated. Our results demonstrated that the biological viability of the pollens collected from the four districts exhibited no significant differences. ELISA and dot blotting results further demonstrated that the serum of sensitized rats exhibited much higher immune-reactive response than that of control groups. Western blotting showed that the 15 KD (1KD = 1000 dalton) proteins of Humulus pollen led to the allergic response. The allergenic intensity of Humulus pollen protein from different samples followed the pattern: WS > JD > XJ > SJ. There was a negative relationship between the allergenicity of Humulus pollens and PM10 (R = -0.99) / PM2.5 (R = -0.73), and a positive relationship with O3 (R = 0.92). These data clearly showed that PM10 and PM2.5 could enhance Humulus pollen protein release, and O3 could aggravate the allergenicity of the Humulus pollen.  相似文献   

15.
Measurements of carbon dioxide (CO2) flux at the soil surface of oil palm (Elaeis guineensis Jacq.) plantations on peatlands typically exhibit considerable temporal and spatial variation, which challenges the derivation of emission factors required in land use discussions. We tested 20 cm surface soil moisture content, and the diurnal patterns in soil and air temperatures as CO2 flux controls during an annual measurement schedule in a 15-year-old oil palm plantation in Jambi Province, Sumatra, Indonesia. A total of 480 CO2 flux measurements were obtained using an Infrared Gas Analyser (IRGA) at six different time intervals each day. Samples were recorded at 20 observation points distributed along four transects located 15, 42, 50, 70, and 84 m from the edge of the drainage canal. Results showed CO2 flux exhibited no relationship to soil and air temperature, however values tended to increase with volumetric soil moisture content; the highest annual flux of 55 Mg ha?1 yr?1 was observed at mid-day, when air temperature was highest, and lowest at dawn when soil and air temperatures were lowest. CO2 flux decreased consistent with distance from the drainage canal, suggesting a higher flux with a deeper water table. This result indicates a shallow water table must be maintained. The annual mean CO2 flux of 46?±?30 Mg CO2 ha?1 yr?1 was comparable to other studies, and can be set as a baseline emissions factor for areas with similar land use and peat characteristics.  相似文献   

16.
摘要:采用水培的方法,研究了不同浓度Mn(0.0003、0.5、1、2、4、8 mmol•L-1)对Mn超富集植物短毛蓼(Polygonum pubescens Blume)和水蓼(Polygonum hydropiper L.)叶片铵态氮、硝态氮、游离脯氨酸、可溶性蛋白质含量及氮素代谢关键酶:硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合酶(GOGAT)和谷氨酸脱氢酶(GDH)活性的影响。结果表明,随着Mn处理浓度的增加,短毛蓼和水蓼的根、茎、叶中Mn含量显著增加(p < 0.05),在相同Mn处理浓度下短毛蓼中的Mn含量均大于同部位水蓼中的Mn含量。在Mn处理浓度小于1 mmol•L-1时,Mn对短毛蓼的株高、株重影响不明显,但对水蓼的影响显著(p < 0.05),表明短毛蓼比水蓼更耐Mn污染。Mn处理显著降低了短毛蓼硝态氮含量(p < 0.05),提高了可溶性蛋白质含量,8 mmol•L-1的Mn处理显著提高了水蓼硝态氮、铵态氮、可溶性蛋白质含量以及短毛蓼、水蓼游离脯氨酸含量,在Mn浓度为8 mmol•L-1时,短毛蓼、水蓼叶片中游离脯氨酸的含量分别为对照的1.18倍和1.68倍,表明游离脯氨酸在解Mn毒害过程中起重要作用。Mn引起了短毛蓼和水蓼氮素代谢关键酶活性的变化,显著降低了水蓼叶片NR、短毛蓼叶片GS活性(p < 0.05);在Mn处理浓度为1 mmol•L-1时,短毛蓼叶片NR活性最高,为对照的1.91倍,而2、4、8 mmol•L-1 Mn处理显著降低了短毛蓼和水蓼GOGAT活性(p<0.05)。另外,Mn处理显著提高了短毛蓼和水蓼叶片GDH活性(p < 0.05),在Mn处理浓度为8 mmol•L-1时,短毛蓼、水蓼叶片GDH的活性分别为对照的16.29倍和1.29倍。  相似文献   

17.
Antibiotics are widely used in humans and animals, but their transformation from surface water to groundwater and the impact of land uses on them remain unclear. In this study, 14 antibiotics were systematically surveyed in a complex agricultural area in Central China. Results indicated that the selected antibiotic concentrations in surface waters were higher in winter (average: 32.7 ng/L) than in summer (average: 17.9 ng/L), while the seasonal variation in groundwaters showed an opposite trend (2.2 ng/L in dry winter vs. 8.0 ng/L in summer). Macrolides were the predominant antibiotics in this area, with a detected frequency of over 90%. A significant correlation between surface water and groundwater antibiotics was only observed in winter (R2 = 0.58). This study further confirmed the impact of land uses on these contaminants, with optimal buffer radii of 2500 m in winter and 500 m in summer. Risk assessment indicated that clarithromycin posed high risks in this area. Overall, this study identified the spatiotemporal variability of antibiotics in a typical agricultural area in Central China and revealed the impact of land uses on antibiotic pollution in aquatic environments.  相似文献   

18.
Understanding atmospheric mercury (Hg) accumulation in remote montane forests is critical to assess the Hg ecological risk to wildlife and human health. To quantify impacts of vegetation, climatic and topographic factors on Hg accumulation in montane forests, we assessed the Hg distribution and stoichiometric relations among Hg, carbon (C), and nitrogen (N) in four forest types along the elevation of Mt. Gongga. Our results show that Hg concentration in plant tissues follows the descending order of litter > leaf, bark > root > branch > bole wood, indicating the importance of atmospheric Hg uptake by foliage for Hg accumulation in plants. The foliar Hg/C (from 237.0 ± 171.4 to 56.8 ± 27.7 µg/kg) and Hg/N (from 7.5 ± 3.9 to 2.5 ± 1.2 mg/kg) both decrease along the elevation. These elevation gradients are caused by the heterogeneity of vegetation uptake of atmospheric Hg and the variation of atmospheric Hg° concentrations at different altitudes. Organic soil Hg accumulation is controlled by forest types, topographic and climatic factors, with the highest concentration in the mixed forest (244.9 ± 55.7 µg/kg) and the lowest value in the alpine forest (151.9 ± 44.5 µg/kg). Further analysis suggests that soil Hg is positively correlated to C (r2 = 0.66) and N (r2 = 0.57), and Hg/C and Hg/N both increase with the soil depth. These stoichiometric relations highlight the combined effects from environmental and climatic factors which mediating legacy Hg accumulation and selective Hg absorption during processes of organic soil mineralization.  相似文献   

19.
Norovirus (NoV) is an environmental threat to humans, which spreads easily from one infected person to another, causing foodborne and waterborne diseases. Therefore, precautions against NoV infection are important in the preparation of food. The aim of this study was to investigate the survival of murine norovirus (MNV), as a NoV surrogate, on six different food-contact surfaces: ceramic, wood, rubber, glass, stainless steel, and plastic. We inoculated 105 PFU of MNV onto the six different surface coupons that were then kept at room temperature for 28 days. On the food-contact surfaces, the greatest reduction in MNV was 2.28 log10 PFU/coupon, observed on stainless steel, while the lowest MNV reduction was 1.29 log10 PFU/coupon, observed on wood. The rank order of MNV reduction, from highest to lowest, was stainless steel, plastic, rubber, glass, ceramic, and wood. The values of d R (time required to reduce the virus by 90 %) on survival plots of MNV determined by a modified Weibull model were 277.60 h (R 2 = 0.99) on ceramic, 492.59 h (R 2 = 0.98) on wood, 173.56 h on rubber (R 2 = 0.98), 97.18 h (R 2 = 0.94) on glass, 91.76 h (R 2 = 0.97) on stainless steel, and 137.74 h (R 2 = 0.97) on plastic. The infectivity of MNV on all food-contact surfaces remained after 28 days. These results show that MNV persists in an infective state on various food-contact surfaces for long periods. This study may provide valuable information for the control of NoV on various food-contact surfaces, in order to prevent foodborne disease.  相似文献   

20.
To date, only a few attempts have been done to estimate the contribution of Mediterranean ecosystems to the global carbon cycle. Within this context, shrub species, composition and structure of the Mediterranean shrublands developing along the Latium coast (Italy) were analyzed in order to evaluate their contribution to carbon (C) sequestration, also taking into consideration the economic benefits at a national level. The considered shrublands had a shrub density of 1,200?±?500 shrubs ha?1. Shrubs were classified into small (S), medium (M) and large (L), according to their volume (V) and leaf area index (LAI). The total yearly carbon dioxide (CO2) sequestration per species (SCy) was calculated multiplying the total photosynthetic leaf surface area (spt) of each species by the mean yearly photosynthetic rate and the total yearly photosynthetic activity time (in hours). Q. ilex and A. unedo had the highest SCy (46.2?±?15.8 kg CO2 year?1, mean value), followed by P. latifolia (17.5?±?6.2 kg CO2 year?1), E. arborea, E. multiflora, C. incanus, P. lentiscus, R. officinalis, and S. aspera (6.8?±?4.2 kg CO2 year?1, mean value). The total yearly CO2 sequestration per shrub (SCshy) was 149?±?5 kg CO2 year?1 in L, decreasing 30 % in M and 80 % in S shrubs. Taking into account the frequency of S, M and L and their SCshy, the total CO2 sequestration of the Mediterranean maquis was quantified in 80 Mg CO2 ha?1?year?1, corresponding to 22 Mg C ha?1?year?1. From a monetary viewpoint, this quantity could be valued to more than 500 US$ ha?1?year?1. Extending this benefit to the Mediterranean shrublands throughout the whole country, we obtained a nationwide estimated annual benefit in the order of $500 million.  相似文献   

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