The response of climate to perturbations in GHGs is location dependent. Six experiments: control (CTRL); double CH4; double CO2; double N2O; halved CFC11 and halved CFC12 were carried out to reveal the local area response to different GHGs levels in the atmosphere over West Africa. Double CH4, CO2 and N2O generally induce wetness but they also induce localized dryness at the hilly and mountainous areas of SW Ghana, Central Nigeria, Northern Cameroon and South-eastern Central African Republic. Increase in ground temperature is induced by double GHGs with intensified warming at the north by double CO2. However, patches of cooling are induced at the north. Changes in specific humidity induced by double CO2, CH4 and N2O are similar. Intensified tropical easterly jet is induced by double GHGs. A dipole anomaly of wind with positive at the lower latitude and negative at higher latitude is induced at the northern part of West Africa. Significant reduction in cloud water content is induced from 900 to 400 hPa and 0 and 15oN.

Atmospheric aerosols have been found to influence the development of planetary boundary layer (PBL) and hence to aggravate haze pollution in megacities. PBL height (PBLH) determines the vertical extent to which the most pollutant effectively disperses and is a key argument in pollution study. In this study, we quantitatively evaluate aerosol radiation effect on PBL, as well as assessment of surface cooling effect and atmosphere heating effect. All the data are measured at a site of Beijing from 2014 to 2017, of which PBLH is retrieved from micro pulse lidar and aerosol optical depth (AOD) from sunphotometer. Case study shows qualitatively that relative high aerosol load reduces PBLH, and in turn causes a high surface PM₂.₅ concentration. We preliminarily reveal the influential mechanism of aerosol on PBL. The influence of aerosol on the radiation flux of PBL is analyzed, with the correlation coefficient (R) of 0.938 between AOD and radiative forcing of BOA (RFBOA) and R = 0.43 between RFBOA and PBLH. Also, AOD is found to negatively correlate with PBLH (R = −0.41). With the increase of AOD, the cooling effect of surface is enhanced, and further impede the development of PBL. Due to aerosol-induced reduction of PBLH, near surface PM₂.₅ concentration surges and presents an exponential growth following AOD. Then, it is speculated and testified that the relationship between SSA (single scatting albedo) and PBLH would be determined by the location of absorbing aerosol within PBL. The upper PBL absorbing aerosol may decrease PBLH, while the lower absorbing aerosol appear to enhance PBLH. The study probably can provide effective observational evidence for understanding the effect of aerosol on PBL and be a reference of air pollution mitigation in Beijing and its surrounding areas.

The present study utilizes 18 years of long-term (2001–2018) data collected from six active AERONET sites over the Indo-Gangetic Plain (IGP) and the North China Plain (NCP) areas in Southeast Asia. The annual mean (±SD) aerosol optical thickness at 440 nm (AOT₄₄₀) was found high at XiangHe (0.92 ± 0.69) and Taihu (0.90 ± 0.51) followed by Beijing (0.81 ± 0.69), Lahore (0.81 ± 0.43), and Kanpur (0.73 ± 0.35) and low at Karachi (0.52 ± 0.23). Seasonally, high AOT₄₄₀ with corresponding high Ångström exponent (ANG₄₄₀₋₈₇₀) noticed during JJA for all sites, except Kanpur, suggesting the dominance of fine-mode particles, generally associated with large anthropogenic emissions. Climatologically, an increasing (decreasing) trend was observed over IGP (NCP) sites, with the highest (lowest) percentage of departures in AOT₄₄₀ found over Beijing (Karachi). We further identified major aerosol types which showed the dominance of biomass burning, urban-industrial followed by the mixed type of aerosols. In addition, single scattering albedo (SSA), asymmetry parameter (ASP), volume size distribution (VSD), and complex aerosol refractive index (RI) showed significant temporal and spectral changes, illustrating the complexity of aerosol types. At last, the annual mean direct aerosol radiative forcing at the top, bottom, and within the atmosphere for all sites were found in the range from −17.36 ± 3.75 to −45.17 ± 4.87 W m⁻², -64.6 ± 4.86 to −93.7 ± 10.27 W m⁻², and 40.5 ± 6.43 to 68.25 ± 7.26 W m⁻², respectively, with an averaged atmospheric heating rate of 0.9–2.3 K day⁻¹. A large amount of anthropogenic aerosols showed a significant effect of heating (cooling) on the atmosphere (surface) results obviously, due to an increased rate of atmospheric heating. Therefore, the thermodynamic effects of anthropogenic aerosols on the atmospheric circulation and its structure should be taken into consideration for future study over the experimental sites.

In a Daya Bay 120-year dated sediment core(1892–2010), analyses were conducted of grain-size, water content, TOC, TIC, TC, loss on ignition, TN, BSi and TP, to reconstruct the anthropogenic activity history. The entire core was divided into four periods. Multi-parametric measurements, their ratios and interrelations are seen to clearly reflect the development of agriculture, aquaculture, industry and social economy surrounding Daya Bay. The trends of TOC, TOM and BSi after 1990 may be due to mass input of nutritious matter from aquaculture and industry, whereas the trends of BSi, TOC and TOM between 1960 and 1990 were owing to aquaculture and agriculture. Two peaks of BSi, TOC and TOM in 1994 and 2002 imply that the mass input of cooling water from nuclear power plants may be a significant contributor to ecological environment changes. Finally, some proposals were put forward for the healthy and sustainable development of Daya Bay.

Dust storms affect the primary productivity of the ocean by providing necessary micronutrients to the surface layer. One such dust storm during March 2012 led to a substantial reduction in visibility and enhancement in aerosol optical depth (AOD) up to ~ 0.8 (AOD increased from 0.1 to 0.9) over the Arabian Sea. We explored the possible effects and mechanisms through which this particular dust storm could impact the ocean’s primary productivity (phytoplankton concentration), using satellite-borne remote sensors and reanalysis model data (2003–2016). The climatological analyses revealed anomalous March 2012 in terms of dust deposition and enhancement in phytoplankton concentration in the month of March during 2003–2016 over this region. The studied dust storm accounts for increase in the daily average surface dust deposition rate from ~ 3 to ~53 mg m⁻² day⁻¹, which is followed by a significant enhancement in the chlorophyll-a (Chl_a) concentration (~ 2 to ~9 mg m⁻³). We show strong association between a dust storm and an event of anomalously high biological production (with a 4-day forward lag) in the Arabian Sea. We suggest that the increase in biological production results from the superposition of two complementary processes (deposition of atmospheric nutrients and deepening of the mixed layer due to dust-induced sea surface temperature cooling) that enhance nutrient availability in the euphotic layer.

In an electrocoagulation process, controlling various parameters, such as temperature, pH, and conductivity, increases the performance of the process. In this study, fuzzy logic algorithms were used to control the temperature of the electrocoagulation system for the removal of pollutants from textile wastewater. In the experimental part, we used a reactor with a cooling jacket to control the temperature, and the flow rate of the cooling water was a variable that we could manipulate. Also, we investigated the use of a single-variable fuzzy control process and a multivariable fuzzy control process to control the dynamic behavior of the system. In the single variable control process, the effect of temperature was investigated at chosen original temperatures, i.e., 17.2 °C, 20 °C, and 23 °C. In the multivariable control, the temperature-pH and temperature-conductivity pairs were controlled separately in different processes. When the removal efficiencies were determined for the two control approaches, it was observed that the temperature-pH control process outperformed the temperature-conductivity control process, and its removal efficiencies for COD, color, and turbidity were about 74.6%, 85.2%, and 91.0%, respectively. Thus, the results obtained from this study will be useful for other investigators in the field. Graphical abstract .