Yangtze Delta Region Of China Research Articles

Does Government Positively Support the Spatial Distribution of ICH? Evidence of Data from the Yangtze Delta Region of China

Intangible cultural heritage (ICH) is humanity’s mutual treasure; the history and civilization of humans are preserved in ICH. In particular, the protection of national ICH has become a principal focus of the Chinese government’s current active promotion of digital protection and innovative ICH development. Since ancient times, the Yangtze Delta region in China has been known as the “country of honey and milk”, and it remains home to many priceless historical and cultural artifacts. This paper combines the Geodetector tool and GIS spatial analysis in order to study as an example the spatial distribution pattern of national ICH in the Yangtze Delta region. The study demonstrates that the quantity and type of structures of national ICH in various provinces and cities differ from one another in terms of spatial distribution characteristics. In general, the spatial agglomeration of ICH is significant, and the spatial divergence between regions is obvious, showing a pattern of spatial distribution characterized by agglomeration in the southeast of the Yangtze Delta region and dispersion in the northwest, presenting different degrees and scales of distribution into groups and bands across each province and city. The indicators of different dimensions were discretized in ArcGIS, then entered into the Geodetector software. The results show that government support is the leading force in promoting the development of ICH, with scores of 0.630 and 0.597 for the secondary indexes. Social humanity serves as an important condition for the development of ICH, and the scores for the relevant secondary indexes were 0.461 and 0.146. Economic development provides the material basis for the further development of ICH, and the scores for these secondary indexes were 0.175 and 0.266. The natural environment determines the basic pattern of the spatial distribution of ICH, and the scores of the relevant secondary indexes in this case were 0.196 and 0.081. The results prove our hypothesis that government support is a core element. Interactions among the factors enhanced their influence on the spatial distribution of ICH. In addition, based on the exploration of the spatial structure of ICH, this research also provides several suggestions for the inheritance and development of ICH in the Yangtze Delta region and puts forward proposals for a future research agenda.

Analyzing the mechanism of spatial–temporal change of green total factor productivity in Yangtze Delta Region of China

Analyzing the mechanism of spatial–temporal change of green total factor productivity in Yangtze Delta Region of China

Poultry to Human Passport: Cross-species Transmission of Zoonotic H7N9 Avian Influenza Virus to Humans

Human infections with H7N9 avian influenza virus were first reported in the early spring of 2013, in the Yangtze-delta region of China. This virus subsequently caused five successive epidemic waves from 2013 to 2018 with highest reported cases in the last wave making this strain the most successful zoonosis influenza virus in humans in recent decades. No H7N9 human infections have been reported since 2019, probably because of the extensive vaccination of poultry. Although zoonoses of H7N9 and other subtypes of avian influenza viral infections remain rare, the virus could acquire sufficient mammalian adaptive mutations to allow it to cause a future influenza pandemic. Here, we summarize the main findings on viral and host factors affecting the interspecies transmission of the H7N9 avian influenza virus.

Characteristics, sources and health risks of toxic species (PCDD/Fs, PAHs and heavy metals) in PM2.5 during fall and winter in an industrial area

Particulate toxic species, such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs) and heavy metals may have significant health risks. This study investigated characteristics, sources and health risks of all three classes of toxic species in PM2.5 (particles with aerodynamic diameter ≤2.5 μm) samples collected at an industrial area in Changzhou, a big city in the Yangtze Delta region of China. Fourteen heavy metals altogether constituted 2.87% of PM2.5 mass, with Fe, Al and Zn as the major elements. Principal component analysis (PCA) suggested that heavy metals came from four sources: vehicles, industry, crustal dust, mixed coal combustion and industrial process. The daily average concentration of 18 PAHs was 235.29 ng/m3, accounting for 0.21% of PM2.5 mass. The dominant PAHs were high molecular weight ones, contributing 73.5% to the total PAHs. Diagnostic analyses indicated that sources of PAHs included vehicle/coal combustion and petroleum emissions, wherein diesel emission played a more important role than gasoline emission. PCA showed that the largest contributor of PAHs was vehicle exhaust mixed with coal combustion, followed by three industry-related sources. Total concentration of 17 PCDD/Fs varied between 3.14 and 37.07 pg/m3, with an average of 14.58 pg/m3. The 10 PCDFs accounted for 70.5% of total concentration of 17 PCDD/Fs. Health risk assessments showed that the carcinogenic risk of heavy metals was acceptable, while risks from PAHs and PCDD/Fs cannot be ignored. Back trajectory analysis indicated that local/regional transported air masses from northern China was the major source areas of the toxic species.

Spatio-Temporal Change and Pollution Risk of Agricultural Soil Cadmium in a Rapidly Industrializing Area in the Yangtze Delta Region of China.

The impacts of rapid industrialization on agricultural soil cadmium (Cd) accumulation and their potential risks have drawn major attention from the scientific community and decision-makers, due to the high toxicity of Cd to animals and humans. A total of 812 topsoil samples (0–20 cm) was collected from the southern parts of Jiangsu Province, China, in 2000 and 2015, respectively. Geostatistical ordinary kriging and conditional sequential Gaussian simulation were used to quantify the changes in spatial distributions and the potential risk of Cd pollution between the two sampling dates. Results showed that across the study area, the mean Cd concentrations increased from 0.110 mg/kg in 2000 to 0.196 mg/kg in 2015, representing an annual average increase of 5.73 μg/kg. Given a confidence level of 95%, areas with significantly-increased Cd covered approximately 12% of the study area. Areas with a potential risk of Cd pollution in 2000 only covered 0.009% of the study area, while this figure increased to 0.75% in 2015. In addition, the locally concentrating trend of soil Cd pollution risk was evident after 15 years. Although multiple factors contributed to this elevated Cd pollution risk, the primary reason can be attributed to the enhanced atmospheric deposition and industrial waste discharge resulting from rapid industrialization, and the quick increase of traffic and transportation associated with rapid urbanization.

Satellite-derived high resolution PM2.5 concentrations in Yangtze River Delta Region of China using improved linear mixed effects model

Satellite remotely sensed aerosol optical depth (AOD) provides an effective way to fill the spatial and temporal gaps left by ground PM2.5 monitoring network. Previous studies have established robust advanced statistical models to estimate PM2.5 using AOD data in China. However, their coarse resolutions (∼10 km or greater) of PM2.5 estimations are not enough to support the health effect studies at urban scales. In this study, 3 km AOD data from Moderate Resolution Imaging Spectroradiometer (MODIS) collection 6 products were used to estimate the high resolution PM2.5 concentrations in Yangtze Delta Region of China. We proposed a nested linear mixed effects (LME) model including nested month-, week-, and day-specific random effects of PM2.5-AOD relationships. Validation results show that the LME model only with day-specific random effects (non-nested model) used in previous studies has poor performance in the days without PM2.5-AOD matchups (the R2 of day-of-year-based cross validation (DOY-based CV) is 0.148). The results also show that our nested model cannot improve the performance of non-nested model in the days with PM2.5-AOD matchups (sample-based CV R2 = 0.671 for nested model vs. 0.661 for non-nested model), but can greatly improve the model performance beyond those days (DOY-based CV R2 = 0.339 for nested model vs. 0.148 for non-nested model). To further improve the model performance, we applied the “buffer models” (i.e., models fitted from datasets which ground PM2.5 were matched with the average AOD values within certain radius buffer zones of gridded PM2.5 data) on the 3 km AOD data since the “buffer models” has more days with PM2.5-AOD matchups and can provide more day-specific relationships. The results of this study show that 3 km MODIS C6 AOD data can be used to estimate PM2.5 concentrations and can provide more detailed spatial information for urban scale studies. The application of our nested LME model can greatly improve the accuracy of 3 km PM2.5 predictions.

Seasonal Variation of Aerosol Optical Properties in an Urban Site of the Yangtze Delta Region of China

ABSTRACTThe characteristics of aerosol optical properties during 2012 at Hangzhou (30°14′N, 120°10′E), an urban site in the Yangtze Delta Region of China, were analyzed, including aerosol scattering and absorption coefficients, aerosol optical depth (AOD), Angstrom exponent (α), single scattering albedo (SSA), and aerosol size distribution. Both aerosol absorption and scattering coefficients were lowest in summer; the highest absorption coefficient was observed in autumn; while the scattering was highest in winter. There were no significant differences in the seasonal average of AOD, with values of approximately 1.0 in spring, autumn and winter, and 0.72 in summer. The averaged Angstrom exponent was found to be relatively high throughout the year, with a minimum value of 1.14 in spring and a maximum of 1.35 in autumn. The fine modes of the aerosol volume size distributions showed the highest peak around radius 0.15 µm in spring, autumn and winter, and radius 0.25 µm in summer, while the coarse modes showed maximum peaks at radius 2.9 µm in all seasons. The volume concentrations of coarse mode aerosols over Hangzhou were highest in spring compared with other seasons. The mean total SSA values were 0.89, 0.93, 0.89 and 0.88 at 440 nm for spring, summer, autumn and winter, respectively, indicating that the aerosols were mainly composed of scattering particles in Hangzhou. Furthermore, it was found continuous pollution events appeared in East China as a result of biomass burning during June 10–13 in 2012. The main causes of extremely severe air pollution and poor visibility in Hangzhou were related to the long-distance transport of pollutants, local pollution emission and stagnant weather conditions. Aerosol optical properties exhibited high value in absorption AOD and high aerosol volumes, low SSA in coarse mode after biomass burning.

Detection of Avian H7N9 Influenza A Viruses in the Yangtze Delta Region of China During Early H7N9 Outbreaks.

Since the first H7N9 human case in Shanghai, February 19, 2013, the emerging avian-origin H7N9 influenza A virus has become an epizootic virus in China, posing a potential pandemic threat to public health. From April 2 to April 28, 2013, some 422 oral-pharyngeal and cloacal swabs were collected from birds and environmental surfaces at five live poultry markets (LPMs) and 13 backyard poultry farms (BPFs) across three cities, Wuxi, Suzhou, and Nanjing, in the Yangtze Delta region. In total 22 isolates were recovered, and six were subtyped as H7N9, nine as H9N2, four as H7N9/H9N2, and three unsubtyped influenza A viruses. Genomic sequences showed that the HA and NA genes of the H7N9 viruses were similar to those of the H7N9 human isolates, as well as other avian-origin H7N9 isolates in the region, but the PB1, PA, NP, and MP genes of the sequenced viruses were more diverse. Among the four H7N9/H9N2 mixed infections, three were from LPM, whereas the other one was from the ducks at one BPF, which were H7N9 negative in serologic analyses. A survey of the bird trading records of the LPMs and BPFs indicates that trading was a likely route for virus transmission across these regions. Our results suggested that better biosecurity and more effective vaccination should be implemented in backyard farms, in addition to biosecurity management in LPMs.

Performance evaluation of public transit systems using a combined evaluation method

The goal of this paper is to evaluate the performance of public transit systems based on a combined evaluation method (CEM) consisting of information entropy theory and super efficiency data envelopment analysis (SE-DEA). Taking 13 transit operators in Yangtze Delta Region of China as the research object, we integrate the public transit industry regulations, transit operation and passenger requirements to construct an evaluation indicator system based on satisfaction and efficiency. The CEM is used to evaluate the performance. The results show significant differences in the efficiency scores between CEM and SE-DEA. The CEM can reduce the risks of SE-DEA affected by the dimensions of indicators, and improve its discrimination capability. The evaluation outcomes of the CEM seem to be more objective, therefore, provide a more suitable basis for decision-making related to public transit service performance, as well as for the study of operation and management.

Occurrence of four mycotoxins in cereal and oil products in Yangtze Delta region of China and their food safety risks

A total of 76 cereal and oil products collected from Yangtze Delta region of China were analyzed for occurrences of aflatoxins (AFs), aflatoxin B1 (AFB1), ochratoxin A (OTA), deoxynivalenol (DON) and zearalenone (ZEN). The mycotoxins were determined by the standard detection procedures using immunoaffinity column clean-up coupled with fluorometer (or HPLC-UV). ZEN was the most prevalent toxin, with the incidence of 27.6% (range = 10.0–440.0 μg kg−1), and 9.2% of the evaluated samples were contaminated with a concentration higher than that of the legislation limit of China (60 μg kg−1). AFs and AFB1 were detected in 14.5% of the samples analyzed, the concentrations ranging 1.1–35.0 μg kg−1 for AFs, and 1.0–32.2 μg kg−1 for AFB1; 4.0% of the samples had the concentrations of AFs and AFB1 higher than that of the corresponding legislation limits of China (5.0, 10.0 and 20.0 μg kg−1 for different products). OTA was detected in 14.5% of the cereal and oil products collected; the concentrations ranged 0.51–16.2 μg kg−1. Only 2 samples showed OTA levels higher than that of the legislation limit of China (5.0 μg kg−1). DON was detected in 7.9% of the samples; the concentrations ranged 100–700 μg kg−1, and none of the samples showed DON concentration higher than that of the legislation limit of China (1.0 mg kg−1). A total of 15.8% cereal and oil products were contaminated with at least two mycotoxins (multiple contaminations with different combinations including AFs-ZEN, AFs-OTA-ZEN, OTA-ZEN, ZEN-DON, OTA-ZEN-DON). The dietary exposure assessment results indicated that AFs (AFB1), OTA, DON and ZEN from cereal-based products represented a series health risk to both adults and children in Yangtze Delta region of China. This is the first report of safety evaluation associated with major mycotoxins for the area.

Seasonal variations of aerosol optical properties, vertical distribution and associated radiative effects in the Yangtze Delta region of China

Four years of columnar aerosol optical properties and a one‐year vertical profiles of aerosol particle extinction coefficient at 527 nm are analyzed at Taihu in the central Yangtze River Delta region in eastern China. Seasonal variations of aerosol optical properties, vertical distribution, and influence on shortwave radiation and heating rates were investigated. Multiyear variations of aerosol optical depths (AOD), Ångstrom exponents, single scattering albedo (SSA) and asymmetry factor (ASY) are analyzed, together with the vertical profile of aerosol extinction. AOD is largest in summer and smallest in winter. SSAs exhibit weak seasonal variation with the smallest values occurring during winter and the largest during summer. The vast majority of aerosol particles are below 2 km, and about 62%, 67%, 67% and 83% are confined to below 1 km in spring, summer, autumn and winter, respectively. Five‐day back trajectory analyses show that the some aerosols aloft are traced back to northern/northwestern China, as far as Mongolia and Siberia, in spring, autumn and winter. The presence of dust aerosols were identified based on the linear depolarization measurements together with other information (i.e., back trajectory, precipitation, aerosol index). Dust strongly impacts the vertical particle distribution in spring and autumn, with much smaller effects in winter. The annual mean aerosol direct shortwave radiative forcing (efficiency) at the bottom, top and within the atmosphere are −34.8 ± 9.1 (−54.4 ± 5.3), −8.2 ± 4.8 (−13.1 ± 1.5) and 26.7 ± 9.4 (41.3 ± 4.6) W/m2 (Wm−2 τ−1), respectively. The mean reduction in direct and diffuse radiation reaching surface amount to 109.2 ± 49.4 and 66.8 ± 33.3 W/m2, respectively. Aerosols significantly alter the vertical profile of solar heating, with great implications for atmospheric stability and dynamics within the lower troposphere.

Transport, vertical structure and radiative properties of dust events in southeast China determined from ground and space sensors

Two dust events were detected over the Yangtze Delta region of China during March 14–17 and April 25–26 in 2009 where such dust events are uncommon. The transport behavior, spatio-temporal evolution, vertical structure, direct radiative effects, as well as induced heating rates, are investigated using a combination of ground-based and satellite-based measurements, a back-trajectory analysis, an aerosol model and a radiative transfer model. Back-trajectories, wind fields and aerosol model analyses show that the first dust originated in northern/northwestern China and the second generated in the Taklimakan desert in northwest China, and traveled across the Hexi corridor and Loess Plateau to the Yangtze Delta region (the so-called “dust corridor”). The mean lidar extinction-to-backscatter ratio (LR) during the two dust events was 38.7 ± 10.4 sr and 42.7 ± 15.2 sr, respectively. The mean aerosol depolarization ratio (δa) for the first dust event was 0.16 ± 0.07, with a maximum value of 0.32. For the second, the mean δa was around 0.19 ± 0.06, with a maximum value of 0.29. Aerosol extinction coefficient and δa profiles for the two events were similar: two aerosol layers consisting of dust aerosols and a mixture of dust and anthropogenic pollution aerosols. The topmost aerosol layer is above 3.5 km. The maximum mean aerosol extinction coefficients were 0.5 km−1 and 0.54 km−1 at about 0.7 km and 1.1 km, respectively. Significant effects of cooling at the surface and heating in the atmosphere were found during these dust events. Diurnal mean shortwave radiative forcings (efficiencies) at the surface, the top-of-the-atmosphere and within the atmosphere were −36.8 (−80.0), −13.6 (−29.6) and 23.2 (50.4) W m−2, respectively, during the first dust event, and −48.2 (−70.9), −21.4 (−31.5) and 26.8 (39.4) W m−2, respectively, during the second dust event. Maximum heating rates occurred at 0.7 km during the first dust event and at 1.1 km during the second dust event, with a maximum value of 2.74 K day−1 for each case. This significant atmospheric heating induced by elevated dust aerosol layers can affect convection and stability in the lower troposphere.

Aerosol optical properties and radiative effects in the Yangtze Delta region of China

One year's worth of aerosol and surface irradiance data from September 2005 to August 2006 were obtained at Taihu, the second supersite for the East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST‐AIRE). Aerosol optical properties derived from measurements by a Sun photometer were analyzed. The aerosol data were used together with surface irradiance data to quantitatively estimate aerosol effects on surface shortwave radiation (SWR) and photosynthetically active radiation (PAR). The annual mean aerosol optical depth at 500 nm is 0.77, and mean Ångstrom wavelength exponent is 1.17. The annual mean aerosol single scattering albedo and mean aerosol asymmetry factor at 440 nm are 0.90 and 0.72, respectively. Both parameters show a weak seasonal variation, with small values occurring during the winter and larger values during the summer. Clear positive relationships between relative humidity and aerosol properties suggest aerosol hygroscopic growth greatly modifies aerosol properties. The annual mean aerosol direct radiative forcing at the surface (ADRF) is −38.4 W m−2 and −17.8 W m−2 for SWR and PAR, respectively. Because of moderate absorption, the instantaneous ADRF at the top of the atmosphere derived from CERES SSF data is close to zero. Heavy aerosol loading in this region leads to −112.6 W m−2 and −45.5 W m−2 reduction in direct and global SWR, but 67.1 W m−2 more diffuse SWR reaching the surface. With regard to PAR, the annual mean differences in global, direct and diffuse irradiance are −23.1 W m−2, −65.2 W m−2 and 42.1 W m−2 with and without the presence of aerosol, respectively.

Direct aerosol radiative forcing in the Yangtze delta region of China: Observation and model estimation

The Yangtze delta region of China is a key agricultural area that experiences relatively high aerosol loadings [Xu et al., 2002]. In order to characterize the aerosol radiative properties and estimate direct aerosol radiative forcing in this region, measurements of the multiwavelength aerosol optical depth, τλ, light scattering coefficient, σsp, and absorption coefficient, σap, as well as the downward photosynthetically active radiation (400–700 nm), DPAR, were conducted during November 1999 in Linan, China. The direct aerosol radiative forcing for photosynthetically active radiation (PAR) and total solar radiation (0.2–4.0 μm, TSR) at both the surface and top of atmosphere (TOA) are estimated based on the measurements using two radiative transfer models. The model estimates indicate that the mean cloud‐free instantaneous direct aerosol radiative forcing efficiency (for solar zenith angle < 70°) at the surface for PAR is −73.5 W m−2, which is in agreement with the value of −74.4 W m−2 derived directly from the measurements of DPAR and 500 nm aerosol optical depth (τ500). On the basis of the measured mean τ500 of 0.61, and the estimated cloud optical depth and cloud coverage of 5.0 and 50%, respectively, the 24‐hr mean direct aerosol radiative forcing at the surface for PAR is estimated to be approximately −11.2 W m−2. This suggests that the amount of PAR reaching the surface over the Yangtze delta region is reduced by ∼16% as a result of the direct radiative effect of aerosols. The model results also indicate that the cloud‐free 24‐hr average direct aerosol radiative forcing efficiency at the TOA for TSR is −30.4 W m−2. When the presence of clouds is considered, the mean direct aerosol radiative forcing at the TOA for TSR is estimated to be approximately −12.1 W m−2. This value is roughly an order of magnitude greater than the estimated global mean aerosol radiative forcing of −0.3 to −1.0 W m−2 suggested by the Intergovernmental Panel on Climate Change [1996]. Overall, this study indicates that aerosols have a substantial impact on the amount of radiation reaching the surface as well as the radiation balance at the TOA in the Yangtze delta region.

Measurement of aerosol chemical, physical and radiative properties in the Yangtze delta region of China

In order to understand the possible influence of aerosols on the environment in the agricultural Yangtze delta region of China, a one-month field sampling campaign was carried out during November 1999 in Linan, China. Measurements included the aerosol light scattering coefficient at 530 nm, σ sp, measured at both dry relative humidity (RH<40%) and under ambient conditions (sample RH=63±19%), and the absorption coefficient at 565 nm, σ ap, for aerosol particles having diameters <2.5 μm (PM 2.5). At the same time, daily filter samples of PM 2.5 as well as aerosol particles having diameters <10 μm (PM 10) were collected and analyzed for mass, major ion, organic compound (OC), and elemental carbon (EC) concentrations in order to determine which anthropogenic chemical species were primarily responsible for aerosol light extinction. The aerosol loading in the rural Yangtze delta region was comparable to highly polluted urban areas, with mean and standard deviation (S.D.) values for σ sp, σ ap and PM 2.5 of 353 Mm −1 (202 Mm −1), 23 Mm −1 (14 Mm −1) and 90 μg m −3 (47 μg m −3), respectively. A clear diurnal pattern was observed in σ sp and σ ap with minimum values occurring in the middle of the day, most likely associated with the maximum midday mixing height. The ratio of the change in light scattering coefficient at ambient RH to that at controlled RH (RH<40%), F σ sp (RH), indicates that condensed water typically contributed ∼40% to the light scattering budget in this region. The mass scattering efficiency of the dry aerosol, E scat_2.5, and mass absorption efficiency of EC, E abs_2.5, have mean and S.D. values of 4.0 m 2 g −1 (0.4 m 2 g −1) and 8.6 m 2 g −1 (7.0 m 2 g −1), respectively. PM 2.5 concentrations in Linan and two other locations in the Yangtze delta, Sheshan and Changshu (which have monthly mean values ranging from ∼80 to 110 μg m −3), are all significantly higher than the proposed 24-h average US PM 2.5 NAAQS of 65 μg m −3. Organic compounds are the dominant chemical species accounting for ∼50% of the PM 2.5 mass at all three sites. The results indicate that aerosol loadings in the agricultural Yangtze delta region of China are relatively high, and suggest that aerosols have a significant impact on visibility, climate, crop production, and human health in this region.

Influence of aerosol dry deposition on photosynthetically active radiation available to plants: A case study in the Yangtze Delta Region of China

In this paper, a new mechanism is proposed by which aerosols decrease the amount of photosynthetically active radiation (PAR) available to plants for photosynthesis. The mechanism involves the scattering and absorption of PAR by water insoluble aerosol particles (WIA) which deposit on leaves and are not washed off by precipitation. A simple model is developed that predicts the change in the transmittance of PAR, TPAR, for plant leaves due to WIA dry deposition as a function of aerosol chemical, physical, and optical properties. Model estimates for the agricultural Yangtze delta region of China indicate that over a 2‐month period during a growing season, dry deposition of WIA may account for a ∼35% reduction in PAR available for plant photosynthesis. Although, the estimate is sensitive to several factors that are uncertain including aerosol dry deposition velocity, leaf area index, and removal rate of particles by precipitation. Results suggest that impacts on crop yields due to aerosol dry deposition could be considerable in this region and suggest a previously neglected economic incentive for China to mitigate air pollution. Additionally, WIA dry deposition may influence carbon uptake by plants in other locations that experience regional haze.

Ozone and related gaseous pollutants in the boundary layer of eastern China: Overview of the recent measurements at a rural site

We present a summary of the latest measurements of ozone (O3) and primary air pollutants at a rural/agricultural site in the fast developing Yangtze Delta region of China. The results of this study show elevated levels of primary pollutants (CO, SO2 and NOx*), which are about 1–5 times of those typically found in rural areas of North America and Europe. O3 pollution events are frequently observed. CO and SO2 levels are particularly high, resulting from the unique energy‐use pattern in China. O3 shows strong positive correlation with NOx* and CO during periods of high photochemical activity. The O3‐NOx* slope is comparable to the result from rural North America, but the O3‐CO slope is substantially smaller for the Chinese site. With the anticipation of rapid changes of atmospheric composition in China, long‐term measurements of key air pollutants will be necessary for documenting their trends and for studying their environmental impacts.

Protective effects of melatonin against apoptosis induced by oxidative stress in cultured cortical neurons and mixed glia

A total of 76 cereal and oil products collected from Yangtze Delta region of China were analyzed for occurrences of aflatoxins (AFs), aflatoxin B1 (AFB1), ochratoxin A (OTA), deoxynivalenol (DON) and zearalenone (ZEN). The mycotoxins were determined by the standard detection procedures using immunoaffinity column clean-up coupled with fluorometer (or HPLC-UV). ZEN was the most prevalent toxin, with the incidence of 27.6% (range = 10.0–440.0 μg kg−1), and 9.2% of the evaluated samples were contaminated with a concentration higher than that of the legislation limit of China (60 μg kg−1). AFs and AFB1 were detected in 14.5% of the samples analyzed, the concentrations ranging 1.1–35.0 μg kg−1 for AFs, and 1.0–32.2 μg kg−1 for AFB1; 4.0% of the samples had the concentrations of AFs and AFB1 higher than that of the corresponding legislation limits of China (5.0, 10.0 and 20.0 μg kg−1 for different products). OTA was detected in 14.5% of the cereal and oil products collected; the concentrations ranged 0.51–16.2 μg kg−1. Only 2 samples showed OTA levels higher than that of the legislation limit of China (5.0 μg kg−1). DON was detected in 7.9% of the samples; the concentrations ranged 100–700 μg kg−1, and none of the samples showed DON concentration higher than that of the legislation limit of China (1.0 mg kg−1). A total of 15.8% cereal and oil products were contaminated with at least two mycotoxins (multiple contaminations with different combinations including AFs-ZEN, AFs-OTA-ZEN, OTA-ZEN, ZEN-DON, OTA-ZEN-DON). The dietary exposure assessment results indicated that AFs (AFB1), OTA, DON and ZEN from cereal-based products represented a series health risk to both adults and children in Yangtze Delta region of China. This is the first report of safety evaluation associated with major mycotoxins for the area.