Key factors affecting urban runoff pollution under cold climatic conditions

The abnormal characteristics of extremely warm early summer (EWES) in North China under different decadal backgrounds were contrastively analyzed. Their relationships with upper- and lower-level atmospheric circulation and global sea surface temperature anomalies (SSTAs) are also discussed. Results show that temperature anomalies of EWES in North China are overall higher than normal in both cold (1961–1993) and warm (1994–2019) periods, but the anomalies of the latter are much higher than that of the former. EWES in North China is directly related to the circulation lying between 40° and 50°N in the middle troposphere, which leads to positive temperature anomalies occurring from the bottom to the upper level of the troposphere together with a high anomaly trend tilting northward. The persistent and strong Eurasian continental high (ECH) and weak Northeast China cold vortex (NECV) activity, together with the strong western Pacific subtropical high (WPSH) are major factors that directly lead to EWES in North China. ECH and WPSH are stronger and larger, and NECV are weaker and more northward in the warm period than in the cold period. In addition, the positive SSTAs in the tropical Indian Ocean and the Kuroshio area are favorable for the stronger and larger ECH and WPSH as well as the weaker and more northward NECV, causing strong anticyclonic and downward circulation system controlling North China, resulting in the extremely warm temperatures there. The joint impact of the positive tropical Indian Ocean SSTAs and the Kuroshio region SSTAs is more significant during warm than cold periods, resulting in much stronger EWES in North China during warm periods.

Glacier-archived records are powerful windows into past climates and ecosystems, but variation in co-preserved microbiota is rarely characterized over long time periods or connected to changing climates. In a 310-meter ice core from the Guliya ice cap, Tibetan Plateau, we linked microbial communities to concomitant climatic conditions across 33 depths, spanning at least the last 150,000 years. Communities differed significantly between cold and warm periods, and among the three major climate epochs Holocene, Last Glacial Stage (LGS), and Pre-LGS. Although source inputs varied during these periods, the microbial changes appeared independently impacted by climate as well. Co-occurrence network analyses suggested the importance of glacial surface-growing communities, and their phototrophs, to the preserved microbial record. The inferred microbial growth (by cell densities, diversity, and potential doubling times pre-compaction into solid ice) on Guliya’s surfaces was higher during cold periods than warm periods, likely associated with deeper snow and firn layers under colder conditions. Three Cyanobacteria “blooms” were captured in the record, and were significantly correlated to overall microbial concentration and diversity, as well as the abundance of two heterotrophic photosynthetic clades (the genus Geodermatophilus and the class Chloroflexia). Taxonomically, 6 genera were historically persistent and dominant throughout the record (Polaromonas, Flavobacterium, Massilia, Aquaspirillum, Pedobacter, and Cryobacterium), one of which (Cryobacterium) exhibited a shift in dominant strains from the Pre-LGS to the LGS, indicating a possible speciation event. Collectively, these findings advance our understanding of ancient glacier-archived microbial communities and the ecological forces they experienced, provide evidence for microbiological responses to the prevailing climate regime, and may shed new light on the microbial evolution across a long-term history over at least the last >150,000 years.

Biological treatment in wastewater treatment plants releases high amounts of pathogenic bioaerosols. Quantitative microbial risk assessment is a framework commonly used for quantitative risk estimation for occupational exposure scenarios. However, the quantitative contributions of health-risk-estimate inputted parameters remain ambiguous. Therefore, this research aimed to study the disease burden of workers exposed to Staphylococcus aureus bioaerosol during warm and cold periods and strictly quantify the contributions of the inputted parameters by sensitivity analysis on the basis of Monte Carlo simulation. Results showed that the disease health risk burden of workers in the warm period was 1.15–6.11 times higher than that of workers in the cold period. The disease health risk burden of workers without personal protective equipment was 23.83–36.55 times higher than that of workers with personal protective equipment. Sensitivity analysis showed that exposure concentration and aerosol ingestion rate were the first and second predominant factors, respectively; the sensitivity partitioning coefficient of the former was 1.17–1.35 times the value of the latter. In addition, no remarkable differences were revealed in the sensitivity percentage ratio between warm and cold periods. The findings could contribute to the mitigation measures for the management of public health risks.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-022-21447-9.

The effect of mixed layer across air mass trajectory pathways on PM2.5 constituent levels: The case of a major urban center in the Eastern Mediterranean

A multi-millennial simulation with the CSIRO Mark 2 coupled global climatic model has been used to determine whether climatic conditions approximate to those experienced by the medieval Norse settlers in Greenland could be identified. The aim of this analysis was to see whether such conditions could be replicated by the natural climatic variability in this unforced simulation, in order to counteract claims that the current observed global warming is merely another example of this type of climatic regime. This view has been expressed in the media in an attempt to refute the existence of a CO2-induced global warming. A 291-year period of above-average temperature followed by a 41-year cooler period were identified in one millennium of the simulation, and subsequently used as an analogue of conditions representative of the time of the Norse settlements. Considerable interannual variability existed in both these periods, but with noticeable positive and negative surface temperature anomalies in the warm and cold periods respectively. Thus the warm period was not a time of uniform benign conditions. Above-average precipitation was also associated with the warm period, and these climatic conditions would have enhanced pasture growth and hay production (the only crop the Norse produced) thereby sustaining the livelihood of the Norse Greenlanders. The climatic conditions associated with the cold period in the model were probably sufficient to limit the survival prospects of the settlers, especially when other, probably more critical, deleterious factors are taken into account. The temperature anomalies replicated in the simulation are similar to the limited proxy data, but may be smaller in magnitude: nevertheless they appear to be sufficiently large to have affected the viability of the Norse Greenlanders. After considering possible climatic mechanisms that could have contributed to these warm and cold periods it was concluded that they are simply a consequence of stochastic influences generated by nonlinear processes in the simulation. Thus this simulation provides no support for the contention that the current global warming is a manifestation of conditions prevailing during the Norse settlements in Greenland.

Polycyclic aromatic hydrocarbons and nitro-polycyclic aromatic hydrocarbons in five East Asian cities: Seasonal characteristics, health risks, and yearly variations

The objective of the current study was to calculate the deposited dose rate in the human respiratory tract arising from particle number (PN) and particle mass (PM) measurements. A main objective was the investigation of deposition pattern and characteristics of the two metrics in the human respiratory tract. The dose rate was estimated for residents at a suburban background location (Chania, Greece). The total dose rate showed two peaks, one in the morning (1.6 × 109 particles/h at 7:00-8:00) and the other one at night (2.1 × 109 particles/h at 21:00-22:00), during the warm period, while the cold period showed two peaks, morning (2.0 × 109 particles/h at 9:00-10:00) and afternoon (3.6 × 109 particles/h at 18:00-19:00). The peaks during the warm period were associated with traffic emissions, whereas the peaks during the cold period were associated with both heating and traffic emissions. A higher dose rate of PN10 was found in the alveolar region while for PM10 it was found in the extrathoracic region. These findings are linked with increased contribution of ultrafine and coarse particles to PN10 (65%-78% and 54%-62% for cold and warm periods, respectively) and PM10 (63% and 55% for cold and warm periods, respectively) concentrations, respectively. The current study showed the importance to use both number and mass aerosol metrics for determining the human exposure and regional dose and their related health effects. The novelty of the current study is the simultaneous measurements of the two particles metrics and the full particle size distributions to make accurate estimates of regional deposited dose.

Drought/flood spatial patterns over eastern China under centennial cold and warm regimes were investigated. The 63-site yearly dry/wet grade data set derived from Chinese historical documents was used, together with an up-to-date 2000-year long temperature series reconstructed from synthesis of 28 temperature proxies in China. We defined the index of difference between drought and flood frequency to reconstruct the drought/flood spatial patterns for five cold periods (440-540, 780-920, 1390-1460, 1600-1700, and 1800-1900 CE) and four warm periods (650-750, 1000-1100, 1190-1290, and 1900-2000 CE). The results showed that there are no consistent patterns over eastern China among all cold/warm periods. However, for most warm periods, drought (flood) dominated north (south) of the Yangtze River. The ensemble mean drought/flood spatial patterns for all warm periods illustrated a dipole pattern with drought (south of 25°N)-flood (25°-30°N)-drought (north of 30°N), with the exception of flood in the Loess Plateau. For all cold periods, the ensemble mean drought/flood spatial patterns showed an east to west distribution, with flood east of 115°E and drought dominant west of 115°E, with the exception of flood between approximately110°E and 105°E. These differences in ensemble mean drought/flood patterns suggest that the probability of drought north of the Yangtze River and flood in the valleys of the XiangJiang and GanJiang rivers south of the Yangtze River is higher in warm periods than in cold periods.

Urban stormwater runoff is an important source of pollution in receiving water bodies, mainly in cities in development. However, strategies to deal with the impacts caused by the runoff discharges, such as implementing a sustainable urban drainage system (SUDS) with optimized management, need information usually obtained through monitoring studies. Brasília is a city that has one of the highest urban growth rates in Brazil, with significant impacts on urban water resources, including diffuse pollution, generated by new unregulated urban developments that initially start being built with precarious sanitation infrastructure. The Vicente Pires (VP) watershed is highly urbanized and comprises two areas that have been intensively occupied more recently, at a fast pace, and do not have yet basic sanitation systems fully implemented. Stormwater quality at the outlet of the VP watershed was analyzed by monitoring the rainfall, runoff flows, and pollutant concentration. Event Mean Concentration (EMC) and first-flush (FF) phenomenon were calculated, and hydrologic characteristics were compared for different events through correlation analysis. During dry periods the flow varied between 0.5 and 1.29 m3/s, while in flood periods the maximum value was 72.17 m3/s, forming floods with great volume. Nitrate during dry periods stands out with its high concentration; the maximum was 1.49 mg/L, while the maximum concentration during the flood events was 0.43 mg/L, probably due to dilution. Ammonia results showed very low values, probably because nitrification is occurring up to the collection point. The EMC values of solids in flood events were higher and can be attributed to river bed scour along the VP watershed. The EMC SS values for the VP watershed are also similar to areas in the initial stages of building development. The EMC values in the dry season indicate strong correlations between some water quality parameters such as NH+3-N and SS, TS and NO−3-N; NO−3-N, and COD. These correlations indicate that these pollutants are probably being generated by the same source, probably sewage discharges. During flood events, the correlation between pollutant loads and peak flow can be associated with the scouring during surface washing off, because greater concentrations of solids and organic matter occur in events with greater flow rates. For the first 30% of the initial runoff volume, about 29% of SS, 38% of NH+3-N, and 35% of reactive P were carried during flood events. It was verified that large values of maximum or mean rainfall intensity are related to the occurrence of First Flush (FF) for most pollutants. Antecedent dry days (ADD) did not influence build-up processes in this watershed; however, they are related to FF occurrence. Data indicate that the sewage and stormwater collection networks were being installed caused a high impact on observed water quality, with high concentrations of solids during flood events. On the other hand, the wastewater collection after the sewer network installation led to a decrease in COD concentrations over time. For sustainable management of diffuse pollution, the adoption of distributed SUDS to enhance runoff volume reduction is a recommended solution for the case.

Storm events strongly influence water temperatures in the saturated substrate underlying stream channels, or the hyporheic zone (HZ). The goal of this study was to evaluate the impacts of storm events on thermal transport in the HZ. A year of temperature data were collected from six (6) multi-level samplers at multiple depths (30 cm, 60 cm, 90 cm and 150 cm) and were categorized into seasonal storm events. Analysis of the HZ temperature profiles revealed a seasonal reversal in the post-storm temperature change (ΔT) in the substrate. Increases in the ΔT were observed in the warm period (summer), whereas decreases occurred during the cold period (winter); both were associated with the direction of the pre-storm thermal gradient between the stream and substrate temperatures. The amplitude of ΔT became muted with increasing depth. Two-sample t-test analyses showed statistically significant differences between the pre- and post-storm temperatures at all depths during the warm period and at all depths except 150 cm in the cold period. Upwelling groundwater moderates the thermal response. There were no statistically significant differences in the pre- and post-storm stream temperatures during both the cold and warm periods.

Seasonal efficiency of a hybrid sub-surface flow constructed wetland system in treating milking parlor wastewater at northern Hokkaido

Salt Lake County (SLCo), Salt Lake City (SLC) and Utah department of Transportation (UDOT) have been permitted under the Municipal Phase I National Pollutant Discharge Elimination System (NPDES) program since 1995. Stormwater runoff monitoring and wet and dry weather screenings have been conducted since 1992 on nine outfall locations located throughout Salt Lake County. A total of 13 storm events have been sampled up to 1999. Annual pollutant loads and event mean concentrations (EMC) were calculated for total suspended solids (TSS), trace metals, total phosphorus, and biological oxygen demand for three primary landuse types residential, transportation, and commercial/industrial. Annual pollutant loads for transportation and commercial/industrial landuses were determined to be the greatest contributor to all major pollutants. EMCs for all six major pollutants were found to fall within the range of values reported by several municipalities across the country with a similar climate type. The calculated EMCs also compared reasonably with the National Urban Runoff Program (NURP) data for Salt Lake County.

Regular lidar measurements of the vertical aerosol distribution were conducted in Tomsk (56° N, 85° E) from March 2006 to October 2007 as part of the CISLINET (CIS Lidar Network) project. The statistical analysis of the profiles of the aerosol backscattering coefficients β a (532 nm), extinction coefficients σ a (532 nm), and lidar ratio S a (532 nm) from the data of nocturnal measurements by Raman lidar (532 and 607 nm) in the altitude range from 0.45 to 7 km is presented. According to these measurements, the mean height of the top boundary of the boundary layer (BL) is 1.22 km for the cold period of observations (from October to March) and 2.3 km for the warm period (from April to September). The mean value of σ a (532 nm) for the cold period of observations in the BL is 0.025 km−1, which is more than two times lower than the mean value of 0.061 km−1 for the warm observation period. The mean value of S a (532 nm) in the BL is independent of the observation season and is equal to 52 sr. Above the BL, in the free troposphere (FT), the coefficients β a (532 nm) and β a (532 nm) are proportional to the molecular scattering coefficient. The mean value of σ a (532 nm) is 0.0083 km−1 for the cold period and 0.011 km−1 for the warm period. The lidar ratio in the FT is 43.5 sr in the cold period. This value is nearly 10 sr lower than the mean lidar ratio for the warm period (52.8 sr).

This study evaluated the concentrations and emission rates of ammonia and hydrogen sulfide from a wastewater storage pond, manure processing area, and composting area from a 5,000 cow freestall scrape dairy located in south-central Idaho over a 6-month period. Pollutant concentrations were measured using an Ultraviolet Differential Optical Absorbance Spectrometer and emission rates were calculated using backward Lagrangian modeling via the WindTrax model. Measurements were collected continuously at a final 15-minute integration time. Significant seasonal variability in both concentrations and emission rates of all pollutants were observed between warm (5/31/05 9/14/06) and cold (9/15/06 12/7/06) periods. Average summertime concentrations adjacent to a 9.8 hectare wastewater storage pond were found to be 556.3 ppb for NH3 and 33.4 ppb for H2S, with emission rates averaging 28.5 g/m2/s and 4.3 g/m2/s, respectively. During the cold period, concentrations were found to average 366.3 ppb for NH3 and 310 ppb for H2S, with emission rates averaging 18.4 g/m2/s and 41.5 g/m2/s, respectively. These emission rates are similar to those found from dairy lagoons in Ohio, Texas, and Washington. Average concentrations downwind of a 13.3 hectare composting area during the warm period were found to be 472.2 ppb for NH3 and 83.1 ppb for H2S, with average emission rates of 33.4 g/m2/s and 15.9 g/m2/s, respectively. During the cold season, average downwind concentrations were 270.7 ppb for NH3 and 461.7 ppb for H2S, and emission rates averaged 17.3 g/m2/s and 81.6 g/m2/s, respectively. These emission rates for ammonia were similar to those observed in Texas and Washington.

The problems of the microclimate in the production premises lead to an increase in energy costs for the station's own needs and a deterioration in the well-being of the maintenance staff. To avoid this, it is first necessary to analyze the variations of the main parameters. Therefore, the main building (boiler and turbine shop) was chosen for the study Ivanovo CHPP-2. The pilot study was conducted twice a month between 2020 and 2023. As a result of the research, experimental data on the main indicators of the microclimate of the main building of thermal power plants were obtained. The microclimate parameters were measured at the main operating levels in the turbine and boiler rooms during warm and cold periods of the year. The analysis of the obtained data on the microclimate revealed deviations of a number of parameters from the normal values such as temperature, humidity and concentration of volatile substances. The total temperature deviation from the norm in the boiler turbine shop was 15 °C in the warm period, and 7.2 °C in the cold period. Humidity differed by 7.12% in the warm period and by 12.26 °C in the cold period. The maximum deviation of the concentration of volatile organic substances in the air was 6.87 mg/m3.