The air-pollution control system of a lead-acid-battery recycling industry was studied. The system comprised two streams with gravity settlers followed by filter bags for the factory indoor air and the metal-recycling furnace, respectively. Efficiency in particle removal according to mass was found to be 99.91%. Moreover, filter bags and dust from the gravity settlers were analyzed for heavy metals by Wavelength Dispersive X-Ray Fluorescence. The results showed high concentrations of Pb and Na in all cases. In the filter bag samples from the indoor atmosphere stream, Ca, Cu, Fe, and Al were found in concentrations higher than that in the filter bag samples from the furnace stream. The opposite was found for Na. Tl and K were only found in furnace stream bag filters. The elemental concentration of the dust from the furnace fumes stream contained mainly Fe, Na, Cd, Pb, Sb, and Cl, while the indoor main stream contained mainly P, Fe, Na, Pb, and Sb. In all cases, impurities of Nd, Ni, Rb, Sr, Th, Hg, and Bi were found. The high efficiency of the air-pollution control system in particle removal shows that a considerable reduction in emissions was achieved.

One of the main sources of global warming is greenhouse gasses; the most important of which is carbon dioxide. Reducing CO₂ emissions, and its utilization or storage, is a global challenge to tackle climate change. In this work, the operating conditions of the pilot CO₂ capture unit are studied using the ASPEN PLUS^® software. This study describes the methodology of the simulations and the main results. The unit consists of one scrubber and one stripper. For carbon dioxide absorption from gas streams, the aqueous solvent K₂CO₃ is used. The effect on the absorption of CO₂, and regeneration of carbon dioxide and potassium carbonate were studied by varying parameters of pressure, temperature, and concentration of solvent. For each parameter, three values were evaluated with the following ranges: pressure 0.3–1 bar; temperature 80–100 °C; and concentration of potassium carbonate 15–25 wt%. The optimum operating conditions of the pilot unit are pressure of 0.3 bar, stripper temperature of 100 °C, and solvent concentration of 15 wt%. Under these conditions, 99.91% CO₂ capture and 85.46% CO₂ regeneration were achieved. The present research aims to find the optimal operating parameters of the pilot plant to validate the model with the experimental data. In this way, the model parameterization can be used to design large-scale CO₂ capture units.

Simple algorithms are presented for the relationships between the gravimetrically measured PM2.5 mass concentration and a nephelometer particle scattering coefficient, for three different environments: two outdoor locations (an urban and a suburban) and one indoors. With these algorithms, the aerosol light scattering coefficients of the nephelometer (provided on line with a time step of seconds) can be related to PM2.5 mass concentrations. The effect of the relative humidity on the nephelometer readings was also evaluated with two models. In the last two campaigns (in the suburbs of the city and in a laboratory), a drying device before the aerosol entrance to the nephelometer was used, a Nafion™ dryer. In the indoor environment, the two methods (the gravimetric and the nephelometry) were compared with the readings of an aerosol light scattering spectrometer, which provide PM2.5 volume concentrations and thus it was possible to calculate the PM2.5 density indoors.

The contribution of emissions from the stack of a lead battery recycling plant to atmospheric lead concentrations and, eventually, to the topsoil of the surrounding area, were studied. A Gaussian dispersion model, of the American Meteorological Society/United States Environmental Protection Agency Regulatory Model, (AERMOD) was used to determine atmospheric total suspended particulate lead dispersion, which originated from stack emissions, over the wider study area. Stack emission parameters were obtained from online measurements of the industry control sensors. AERMOD simulated two scenarios for four calendar years, 2015 to 2018, one for the typical stack measured operating conditions and one for the legal limit operating conditions (emissions from the stack set by legislation to 0.5 mg m⁻³). Deposition fluxes modeled the input of atmospheric total suspended particulate Pb to the topsoil of the area. X-ray fluorescence (XRF) analyses were used to determine lead concentrations in the topsoil. The modeling results were compared with topsoil of six inhabited locations downwind from the stack in the direction of the prevailing winds to estimate the influence of lead deposition on topsoil near the industrial area.

The spread of the COVID-19 pandemic, effected the imposition of personal protection measures in a large number of countries. The use of commercially available personal face masks was widely accepted as such a protective measure. Since the quality of the face masks scanned the spectrum from surgical to the home made fabric ones, it was considered appropriate to experimentally establish their effectiveness for stopping aerosol in entering the respiratory system of the bearer. Presently, only eight masks were tested with polydisperse indoor air. Their effectiveness was examined for aerosol of aerodynamic diameters of 0.006 μm to 10 μm. Of these masks, only two were effective for the whole range of aerosol. Cloth masks were found to be ineffective for the assigned task.

The decomposition kinetics of non-volatile n-alkanes that were collected in an urban environment were studied. The quartz filters that they were collected on were exposed in two reactors, in dark and natural light conditions, for four days. Ambient air that was passed through the reactors continuously, ensured a supply of exogenic oxidants to the surface of the filters. The lifetimes of the non-volatile n-alkanes were experimentally determined to be in the order of 3–6 days. The results from the light reactor exhibited approximately a 10% decrease in their lifetime. The results obtained for the prevailing atmospheric conditions and for the duration of the experiments, were in agreement with values from the literature.