Monitoring of Compound Air Pollution by Remote Sensing in Lanzhou City in the Past 10 Years

Based on satellite remote sensing data acquired by the Ozone Monitoring Instrument (OMI), this study used pixel space analysis, a coefficient of variation, stability analysis, and an atmospheric transmission model to determine the concentration of tropospheric ozone (O3), NO2, HCHO, and SO2 columns in Lanzhou from 2010 to 2019. A series of analyses were carried out on the temporal and spatial distribution of concentration, influencing factors and atmospheric transmission path. The results show that the air pollutants in this area present multi-dimensional characteristics and have a complex spatial distribution. In terms of inter-annual changes, in addition to the increase in the concentration of the HCHO column, the ozone, NO2, and SO2 column concentrations have all decreased over time. In terms of monthly average changes, these four pollutants reached their maximum values in April, December, June, and January, respectively. These four types of pollution had a strong spatial correlation, among which HCHO and SO2 had a significant positive correlation, with a correlation coefficient of 0.76. Many factors affect the Atmospheric Compound Pollution in Lanzhou. Among them, pollutants are closely related to urbanization and to the activities of coal-burning industries. Moreover, temperature, precipitation, and sunshine also have certain effects on air quality. The proliferation of pollutants in Gansu Province was one of the sources of pollutants in Lanzhou, while long-distance transportation in the atmosphere from outside the province (Qinghai, Sichuan, and Shaanxi) also exacerbated the pollution in Lanzhou.

Effects of Rare Earth Elements on Bacteria in Rhizosphere, Root, Phyllosphere and Leaf of Soil-Rice Ecosystem

The effects of rare earth mining on rice biomass, rare earth element(REE) content and bacterial community structure was studied by pot experiment. The research showed that the REE content in rice roots, shoots and grains was significantly positive correlated with that in soil, and the dry weight of rice roots, shoots and grains was highly correlated with soil physical and chemical properties, nutrient elements and REE contents; The exploitation of rare earth minerals inhibited a-diversity of endophytic fungi in rhizosphere, root, phyllosphere and leaf of rice, significantly reduced the abundance index, OTU number, Chao, Ace index and also significantly reduced the diversity index-Shannon index and Inv-Simpson index, also reduced uniformity index: Pielou’s evenness index, Simpson’s evenness index, etc, which caused β-diversity of bacteria to be quite different. The exploitation of rare earth minerals reduces the diversity of bacteria, but forms dominant bacteria, such as Burkholderia, Bacillus, Buttiauxella, Acinetobacter, Bradyrhizobium, Candida koribacter, which can degrade the pollutants formed by exploitation of rare earth minerals, alleviate the compound pollution of rare earth and ammonia nitrogen, and also has the function of fixing nitrogen and resisting rare earth stress; The content of soil available phosphorus in non mining area is low, forming the dominant bacteria of Pantoea, which has the function of improving soil phosphorus availability. Rare earth elements and physical and chemical properties of soil affect the community structure of bacteria in rhizosphere and phyllosphere of rice, promote the parallel movement of some bacteria in rhizosphere, root, phyllosphere and leaf of rice, promote the construction of community structure of bacteria in rhizosphere and phyllosphere of rice, give full play to the growth promoting function of Endophytes, and promote the growth of rice. The results showed that the rice biomass in mining area was guaranteed due to the growth promoting effect of endophytic bacteria, However, the mining of mineral resources causes the compound pollution of rare earth and ammonia nitrogen, which makes REE content of rice in mining area significantly higher than that in non mining area.

Robust Environmental Sensing Using UAVs

In this article, we first investigate the quality of aerial air pollution measurements and characterize the main error sources of drone-mounted gas sensors. To that end, we build ASTRO+, an aerial-ground pollution monitoring platform, and use it to collect a comprehensive dataset of both aerial and reference air pollution measurements. We show that the dynamic airflow caused by drones affects temperature and humidity levels of the ambient air, which then affect the measurement quality of gas sensors. Then, in the second part of this article, we leverage the effects of weather conditions on pollution measurements’ quality in order to design an unmanned aerial vehicle mission planning algorithm that adapts the trajectory of the drones while taking into account the quality of aerial measurements. We evaluate our mission planning approach based on a Volatile Organic Compound pollution dataset and show a high-performance improvement that is maintained even when pollution dynamics are high.

The Role of Ni and Cd-Resistant Rhizobacteria in Promotion of Rice Seedlings Growth and Alleviation Combined Phytotoxicity of Ni and Cd

The heavy metal compound pollution is becoming a serious problem in the environmental management. In the present study, we focused on the combined pollution of nickel (Ni) and cadmium (Cd) and isolated three Ni and Cd-resistant rhizobacteria (strains Y3, Y4 and Y5) with important PGP traits. According to 16S rDNA sequence homology, strains Y3, Y4 and Y5 were identified as Pseudomonas sp., Chryseobacterium sp. and Enterobacter sp., respectively. Then the effects of strains Y3, Y4 and Y5 on rice growth under the combined stress of Ni and Cd were examined. The results indicated that strains Y3, Y4 and Y5 enhanced the seed germination, biomass production and chlorophyll accumulation of rice seedling under compound stress of Ni and Cd. These strains also conferred rice tolerance to Ni and Cd by increasing antioxidant enzyme activity in seedlings. Furthermore, comparing among three strains, it was found that strain Y3 with stronger ability of IAA production, EPS production and ACC deaminase activity had the best promotion effect on rice growth under the combined stress of Ni and Cd. In addition, strain Y5 had better IAA production capacity and a better effect on the growth of rice roots than strain Y4 under Ni and Cd stress, which indicated that IAA production might play a particularly critical role in root growth under the stress of Ni and Cd.

Large-scale synoptic drivers of co-occurring summertime ozone and PM_2.5 pollution in eastern China

Surface ozone (O3) pollution during summer (June–August) over eastern China has become more severe in recent years, resulting in a co-occurrence of surface O3 and PM2.5 (particulate matter with aerodynamic diameters ≤ 2.5 µm in the air) pollution. However, the mechanisms regarding how the synoptic weather pattern (SWP) might influence this compound pollution remain unclear. In this study, we applied the T-mode principal component analysis (T-PCA) method to objectively classify the occurrence of four SWPs over eastern China, based on the geopotential heights at 500 hPa during summer (2015–2018). These four SWPs over eastern China were closely related to the western Pacific subtropical high (WPSH), exhibiting significant intra-seasonal and interannual variations. Based on ground-level air quality observations, remarkable spatial and temporal disparities of surface O3 and PM2.5 pollution were also found under the four SWPs. In particular, there were two SWPs that were sensitive to compound pollution (Type 1 and Type 2). Type 1 was characterized by a stable WPSH ridge with its axis at about 22∘ N and the rain belt located south of the Yangtze River Delta (YRD); Type 2 also exhibited WPSH dominance (ridge axis at ∼ 25∘ N) but with the rain belt (over the YRD) at a higher latitude compared to Type 1. In general, SWPs have played an important role as driving factors of surface O3–PM2.5 compound pollution in a regional context. Our findings demonstrate the important role played by SWPs in driving regional surface O3–PM2.5 compound pollution, in addition to the large quantities of emissions, and may also provide insights into the regional co-occurring high levels of both PM2.5 and O3 via the effects of certain meteorological factors.

Groundwater Quality and Risk Assessment of Heavy Metal Pollution in Middle-West Part of Bangladesh

Bangladesh is a densely populated and developing country that faced severe water contamination, crisis, and security. About 100% of the population has access to the availability of freshwater, but the purity of water is always concerned. The groundwater of Bangladesh is under increasing threat from overexploitation, population growth, rapid urbanization, and pollution from industries, domestic and agricultural sources. For the assessment of heavy and toxic metal contamination in shallow groundwater, the study collected 40 water samples from different stations in the middle-west part of Bangladesh. The results showed that three metals ion, viz. iron, manganese, and lead exceeded the concentration limit of WHO (2011) in most of the water samples indicating severe human health hazard. The single-factor pollution index (I i ) and compound pollution index (CPI) value of these three (3) metals were very high, i.e., much greater than 1. The other metal concentrations were found within the safe permissible ranges. The values of heavy metal pollution indices, viz. heavy metal pollution index (HMPI), heavy metal evaluation index (HMEI), degree of contamination (Cd ), Nemerow Index (NeI), and ecological risk measurement (ERI) showed that most of the water samples were found medium to high levels of contamination in the study area. The analysis results revealed that an average of 32.6%, 15.6%, and 51.8% of the water samples was found low, medium, and high risk from heavy metal, respectively. There were 20 samples found highly contaminated with heavy metals out of 40 samples. The study results revealed that both the geogenic and anthropologic activities influenced the groundwater system of the area. It suggested that the groundwater quality should go under a continuous monitoring process for sustainable water quality management in the area. The study findings could help with further planning of potential future remediation measures for policymakers.

Analysis of Spatio-Temporal Variation Characteristics of Main Air Pollutants in Shijiazhuang City

Air pollution has become one of the important concerns of environmental pollution in the Beijing–Tianjin–Hebei region. As an important city in Beijing–Tianjin–Hebei, Shijiazhuang has long been ranked in the bottom ten in terms of air quality in the country. In order to effectively grasp the influencing factors and current distribution of air pollution in Shijiazhuang City, this paper collects data on the top air pollutants in Shijiazhuang from 2017 to 2019, analyzes the characteristics of time changes in the region, and uses the Kriging interpolation method to affect the air pollutants in this area. The spatial distribution characteristics are studied. The results show (1) From 2017 to 2019, the environmental quality of Shijiazhuang City showed a decreasing trend except for O3. (2) Seasonal changes show that NO2, PM2.5, and CO show as winter > autumn > spring > summer, PM10, SO2 show as winter > spring > autumn > summer, and O3 concentration changes as summer > spring > autumn > winter. (3) The daily change trends of NO2, SO2, PM10 and PM2.5 are similar, while the change trends of O3 and NO2 are opposite. (4) The correlations between air quality index (AQI) and concentrations suggest that PM10, PM2.5, and CO contribute the most to undesirable pollution levels in this area, while NO2, SO2, and O3 contribute less to undesirable pollution. We have concluded that the particulate pollution in Shijiazhuang City has been effectively controlled, thanks to the relevant measures introduced by the government, but the O3-based compound pollution is gradually increasing, so particulate pollution and O3 pollution need to be treated together. The research results of this article have important practical significance for urban or regional air environment monitoring and prevention.