This paper presents a 120-day-long variability of chemical composition of submicron particulate matter (PM1) over Warsaw. The content of the following components was examined in the PM1 mass: primary (POM) and secondary (SOM) organic matter, secondary inorganic matter (SIM), elemental carbon (EC) as well as Na and Cl ions (primary inorganic matter). The 24-hour concentrations of PM1 were subject to seasonal fluctuations which are typical of urban areas in Poland; their values averaged 11 µg m–3 in summer and 17 µg m–3 in winter. Most of the PM1 components and gaseous pollutants (SO2, NO2 and NOx) revealed higher mean concentrations in winter than in summer. A statistical analysis of meteorological parameters and 24-h concentrations of PM1, PM10, SO2, NO2 and NOx confirmed a significant influence of air temperature and precipitation on the concentration patterns of these pollutants over Warsaw. The highest concentrations of PM1 occurred in winter for the following wind directions: S, SE, N and NE; in summer for NE, E and S. The analysis of back trajectories demonstrated that on days with the highest 24-h concentration of PM1 polluted air masses arrived from S and SE and affected the concentration of PM1 over Warsaw. The submicron particulate matter, in as much as 62%, comprises secondary matter (SOM and SIM). The primary sources of its precursors and – to a smaller extent – of the primary matter as well – are traffic and combustion of various fuels for the purpose of heat and power generation. Their average contribution to the development of PM1 was 15% and 51%, respectively, for the entire period of observations.

The aim of this study was to investigate how atmospheric air pollutants and meteorological conditions affected atmospheric visibility in the largest Polish agglomeration. The correlation analysis, principal component analysis (PCA) and generalized regression models (GRMs) were used to accomplish this objective. The meteorological parameters (temperature, relative humidity, precipitation, wind speed and insolation) and concentrations of the air pollutants (PM₁₀, SO₂, NO₂, CO and O₃) were recorded in 2004–2013. The data came from the Ursynów-SGGW, MzWarszUrsynów and Okęcie monitoring stations, located in the south of Warsaw (Poland). It was shown that the PM₁₀ concentration was the most important parameter affecting the visibility in Warsaw. The concentration, and indirectly the visibility, was mainly affected by the pollutant emission from the flat/building heating (combustion of various fuels). It changed intensively during the research period. There were also periods in which this emission type did not have a great influence on the pollutant concentrations (mainly PM₁₀) and visibility. In such seasons, the research revealed the influence of the traffic emission and secondary aerosol formation processes on the visibility.

The aim of the research was to determine the influence of the substrate and different drainage materials on retention capacity and runoff water quality from three green roof containers. Phosphates were chosen as the water quality indicator based on their potential adverse impact on water quality in urban rainwater collectors. The field experiment was conducted at the Warsaw University of Life Sciences Water Center meteorological station in years 2013–2015. In terms of precipitation, the monitoring period covered a wet (+147.1 mm), average (+42.7 mm) and dry (− 66.3 mm) year. Leakage from the containers was recorded when the substrate moisture exceeded 20% and precipitation exceeded 3.5 mm/d for washed gravel, or 5.0 mm/d for a polypropylene mat and expanded clay. Phosphates were observed in leachates from all containers, with higher values observed in the second year of monitoring. As the result of this study, it can be concluded that the polypropylene mat and aggregates create different conditions for the formation of the leachate, in both volumes and its chemistry. The drainage layer made from a polypropylene mat is the most effective in terms of rainwater retention capacity and the resulting leachate quality.

The search for simple models of drainage–irrigation systems functioning and management has still been an important research objective. Therefore, we presented a conceptual model based on groundwater dynamics equation along with proper assumptions on water equivalent of transient porosity-i.e., storage in the soil profile based on the long-term experience of the research on drainage-sub-irrigation systems. Several parameters have been incorporated in the model to effectively and comprehensively describe drainage/irrigation time, leakage from the soil profile, the soil moisture content in the root zone, and the shape of the groundwater table on the drainage–sub-irrigation plot. The model was successfully validated on groundwater level data in ditch midspacing on an experimental site located within a valley sub-irrigation system with the advantage of a relatively simple representation of flows through the soil profile. The robust character of the conceptual equation of groundwater dynamics, as well as the approach to its’ parameters, were proved through a close match between the model and observations. This promotes the capacities of the proposed modeling procedure to conceptualize drainage-irrigation development with the impact of external and internal sources of water. The potential was offered for the evaluation of water management practices in a valley system influenced by horizontal inflows from surrounding areas as indicated by calibration results. Future challenges were revealed in terms of water exchange between the plots and validation of soil moisture content modeling.

Management for sustainable river valleys requires balancing their natural values against the need for agricultural and recreational development on surrounding lands. The Southern Całowanie Peatland near the city of Warsaw sits on a sandy terrace and has well preserved Carex and Molinia stands existing in part of the area, especially where water tables are less than 1.5 m below the surface. The existing drainage network in this southern part has been poorly maintained and could be reestablished to help raise water levels for restoration of the peatland. Modflow was used to look at influence of drainage channel water levels on the overall water table height in the area. By raising water levels in the drainage system by 0.5 m it was found that 29% of the area would become suitable for increasing Carex and Molinia communities.