Black carbon (BC) and tropospheric ozone (O3) are two main short-lived climate pollutants also linked to health effects. They are ubiquitous in street canyons, since this environment is a hotspot for traffic-related pollutants due to their particular airflow characteristics, location within the cities and the high density of vehicles and population.We report on BC and O3 concentrations measured in a Brazilian city in November 2014. Measurements of BC at 880 nm wavelength were conducted in a street canyon on the north and south façades and at rooftop level (7 wavelengths, including 880 nm) whereas O3 was recorded only on the south façade. Concurrent meteorological data were gathered at a suburban and a rooftop sites.Clear diurnal patterns were found for BC related to traffic emissions and atmospheric mixing conditions. Ozone peaked in the afternoon in response to maximum photochemical production and at night most likely linked to vertical and/or horizontal transport. By using conditional bivariate probability functions, we identified on-road traffic as the main local source for BC during daytime, and at night an intermittent signal was associated with local waste and biomass burned on the city's outskirts. A complementary air backward trajectory analysis helped conclude that locally produced O3 was enhanced by regional transport from large cities and/or biomass smoke.Mitigation strategies for BC and O3 depletion should target the vehicle fleet, particularly diesel buses, reduction of biomass and waste burning at local level, and decrease of open biomass burning in large areas in Brazil and neighbor countries.

Lagrangian trajectories of water parcels reconstructed using the TRACMASS model from three-dimensional velocity fields by the RCO model for 1965–2004 are used to analyse the temporal scales and the probability for the hits to the nearshore by pollution originating from a major fairway in the Gulf of Finland and transported by surface currents. Increasing the simulation length from 10 to 20days induces a linear increase in particle age, but the pattern of nearshore hits remains the same. A reasonable benefit can be reached by relatively small shifts of certain parts of the present fairway in a few locations. The overall probabilities do not reveal any trend for 1965–2004. The largest changes in the nearshore hits are revealed for the proportion of hits to the opposite nearshore areas. This feature probably reflects an abrupt turn of the geostrophic air-flow over the southern Baltic Sea by ~40° since 1987.

Daily mass concentrations and chemical compositions (elemental carbon, organic carbon, water soluble ions, chemical elements and organic species) of PM were measured continuously in Beijing for one year from June 2010 to June 2011 (365 samples). The seasonal variation of PM mass concentration followed the order of spring 2011 > winter 2010 > summer 2010 > autumn 2010. Organic matter (OM) and secondary inorganic aerosol components (SNA: SO42−, NO3− and NH4+) were the two major fractions of PM during the whole year. Source apportionment by PMF performed on the basis of a full year of data, including both inorganic and organic species, showed that biomass burning, secondary sulfate and nitrate formation, mineral dust, industry, coal combustion and traffic were the main sources of PM in Beijing during 2010–2011. Specifically, comparison among the four seasons shows that the contribution of secondary sulfate and biomass burning, secondary nitrate formation, mineral dust, and coal combustion were the dominating sources of PM in summer, autumn, spring and winter, respectively. The contributions of industry to PM was distributed evenly in four seasons, while traffic contributed more in summer and autumn than in winter and spring. Backward trajectory analysis was applied in combination with PMF and showed that air flow from the South contributed mostly to high PM mass concentrations in Beijing. Meteorological parameters (temperature, wind speed, wind direction, precipitation and mixing layer height) influence such a variation. In general, high relative humidity and low mixing layer height can raise PM mass concentration, while high wind speed and precipitation can reduce pollutants. In addition, wind direction also plays a key role in influencing PM because different wind directions can bring different pollutants to Beijing from different regions.

In order to improve the regeneration speed of Continuous Regeneration-Diesel Particulate Filter (CR-DPF) based on NO2-assisted regeneration, a mathematic model of the NO2-assisted regeneration is developed and verified by experiments and numerical simulation. Furthermore, the influences on regeneration speed from exhaust airflow and filter structure are studied in NO2-assisted regeneration process of CR-DPF. The results show that: the regeneration speed will be increased due to the increase of the volume of the exhaust gas, the temperature of the exhaust gas, the concentration of the NO2 and the concentration of the O2 in exhaust gas, but the regeneration speed will be decreased under other conditions such as m(NO2)/m(PM) being less than its threshold in exhaust gas, the increase of the filter length in CR-DPF or the increase of the channel density when initial amount of the carbon particles in filter being less than its threshold, moreover, thickness of channel wall has no effect on regeneration speed. And the suitable range of values for some key parameters being useful for enhancing regeneration speed and reducing pressure drop of CR-DPF has been provided.

Deammonification process has been studied as an alternative technology for nitrogen removal. This process consists of the association between nitrifying and anammox bacteria, in which the process success is related to aeration, recirculation, and reactor configuration. Considering this, the present study aimed to evaluate the performance of an expanded granular sludge bed (EGSB) reactor on nitrogen removal by deammonification process. Established in a single reactor, it considered the effects of recirculation rate and variation of dissolved oxygen (DO) concentration in microbial community and nitrogen removal efficiency. Thus, two independent tests were conducted: (T1) high recirculation flow rate, performed at 43 L d⁻¹ (Qᵣ/Qᵢₙ = 16), aeration of 30 mLₐᵢᵣ min⁻¹ L⁻¹ ᵣₑₐcₜₒᵣ, and conducted during 16 days; (T2) low recirculation flow rate performed at 6.7 L d⁻¹ (Qᵣ/Qᵢₙ = 2.5), operated for 55 days, divided into three aeration phases: (T2a) 30 mLₐᵢᵣ min⁻¹ L⁻¹ ᵣₑₐcₜₒᵣ, (T2b) 20 mLₐᵢᵣ min⁻¹ L⁻¹ ᵣₑₐcₜₒᵣ, and (T2c) 30 mLₐᵢᵣ min⁻¹ L⁻¹ ᵣₑₐcₜₒᵣ. Results showed that in T1 the high recirculation rate favored nitrifying bacteria prevalence, intensified by reactor turbulence and anammox granules disintegration, changing activity from deammonification to a nitrification process. In addition, T1 reached up to 350 ± 100 mgN L⁻¹ d⁻¹ nitrogen removal rate (NRR). For T2, at low recirculation rate, deammonification process was successfully established with a NRR of 490 mgN L⁻¹ d⁻¹ at Qᵣ/Qᵢₙ = 2.5 and air flow rate of 20 mLₐᵢᵣ min⁻¹ L⁻¹ ᵣₑₐcₜₒᵣ.

Accurately measuring air concentrations of agricultural fumigants is important for the regulation of air quality. Understanding the conditions under which sorbent tubes can effectively retain such fumigants during sampling is critical in mitigating chemical breakthrough from the tubes and facilitating accurate concentration measurements. Using laboratory experiments, we studied the effects of air flow rate (100–1000 mL min⁻¹) and sampling time (2–16 h) on the breakthrough of co-applied chloropicrin (CP) and 1,3-dichloropropene (1,3-D) from 600-mg XAD-4 sorbent tubes. Due to the reversible adsorption of the chemicals, it was not possible to determine a tube adsorption capacity that was true across all flow and sample time conditions. Flow rate exerted the stronger influence on breakthrough, particularly for CP, with flow rates in excess of 200 mL min⁻¹ resulting in significant system losses even at the shortest sampling time (2 h). A flow rate of 200 mL min⁻¹ should therefore not be exceeded, irrespective of flow rate. With the use of a single tube (no backup), sampling times up to 4 h showed no system losses (100 % retention). Using a primary and backup tube, sampling periods up to 16 h also resulted in retention of all the added chemical masses. The information will be useful in establishing effective air quality monitoring programs following fumigation events.

The microclimatic parameters (Ta, RH, E, and CO₂) reflect the indoor quality of the environment. Their relationship, connected with the design of the building, can facilitate the growth of photo/heterotrophic organisms and therefore facilitate the increase of the relative CO₂ production. Taking this into account, the impact of biological proliferation in a historical building is discussed for the Mithraeum of “Casa di Diana” in the archaeological site of Ostia Antica, which is subjected to guided tours. In this work, for the first time, we propose a study on biological monitoring to evaluate the contribution of bioactivity to air quality, with the objective to increase the comfort of visitors and to open the site for more than one day per week, suggesting possible tools providing a good compromise between building conservation and human comfort. In the sense, it has been possible to distinguish the contribution of the plants from the one deriving from humans: high values of carbon dioxide have been recorded during the night and its scarce removal during the day (air flow). The window present is not sufficient to eliminate the CO₂, involving concentrations of CO₂ relatively high in comparison to the proposed limits and guidelines defined by law. The obtained results strongly encouraged the elimination of flora in order to increase the comfort of visitors and to open the house for more than one day per week. Although, this process involves an important economic effort, the present study allows making an objective decision which has an important value in a cultural heritage management. Graphical Abstract CO₂ contribute by bioactivity as damage to human health

The electro-Fenton (EF) process treatment of 0.1-M (rhodamine B) RhB solution was studied with different graphite cathode materials, and graphite felt (GF) was selected as a promising material in further investigation. Then, the degradation performances of gas diffusion electrode (GDE) and graphite felt (GF) were compared, and GDE was confirmed to be more efficient in RhB removal. The operational parameters such as Fe²⁺ dosage and current density were optimized, and comparison among different modified methods—polytetrafluoroethylene-carbon black (PTFE-CB), polytetrafluoroethylene-carbon nanotube (PTFE-CNT), electrodeposition-CB, and electrodeposition-CNT—showed 98.49 % RhB removal by PTFE-CB-modified cathode in 0.05 M Na₂SO₄ at a current density of 50 A/m² and an air flow rate of 1 L/min after 20 min. Meanwhile, after cathode modified by PTFE-CB, the mineralization efficiency and mineralization current efficiency performed absolutely better than the pristine one. Cyclic voltammograms, SEM images, contact angles, and BET surface area were carried out to demonstrate stronger current responses and higher hydrophilicity of GF after modified. The value of biochemical oxygen demand/chemical oxygen demand (BOD₅/COD) increased from 0.049 to 0.331 after 90-min treatment, suggesting the solution was biodegradable, and the modified cathode was confirmed to be stable after ten circle runs. Finally, a proposed degradation pathway of RhB was put forward.

Polytetrafluoroethylene/ferromagnetic nanoparticle/carbon black (PTFE/MNP/CB)-modified graphite felt (GF) was successfully applied as cathode for the mineralization of rhodamine B (RhB) in electro-Fenton (EF) process. The modified cathode showed high decolorization efficiency for RhB solution even in neutral pH condition and without external aeration, achieving nearly complete decolorization and 89.52 % total organic carbon (TOC) removal after 270-min oxidation with the MNP load 1.2 g at 50 A/m². Moreover, the operational parameters (current density, MNP load, initial pH, and airflow rate) were optimized. After that, adsorption isotherm was also conducted to compare the absorption quantity of CB and carbon nanotube (CNT). Then, the surface morphologies of MNPs were characterized by transmission electron microscope (TEM), energy-dispersive X-ray detector (EDX), and Fourier transform infrared spectroscopy (FTIR); and the modified cathode was characterized by SEM and contact angle. Finally, the stability and reusability of modified cathode were tested. Result uncovered that the PTFE/MNP/CB-modified cathode has the potential for industrial application and the solution after treatment was easily biodegradable.