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A study was carried out in a waste sorting plant (WSP) located in France, treating dry recyclable household waste (DRHW) as well as dry recyclable commercial and industrial waste (DRCIW). Stationary and personal inhalable samples were collected in the WSP in order to investigate bioaerosols (sampling on a filter; 2 L/min and 10 L/min) and airborne dust (CIP; 10 L/min). The aim of the study was to assess the extent to which the measurement of concentration, species composition, and particle size distribution contributes to a better assessment of the biological risks associated with exposure. The results confirmed that waste and waste sorting activities are sources of airborne fungi. Indeed, ambient concentrations ranged from 7.3 × 103 to 8.5 × 105 colony-forming units (CFU)/m3 for culturable fungi and up to 4 mg/m3 for dust. Personal exposure to inhalable dust was found up to 3 mg/m3 for dust and ranged from 8.6 × 103 to 1.5 × 106 CFU/m3 for fungi. Airborne fungal communities were found to be dominated by the Penicillium genera in both bioaerosols and settled dust samples, followed by the Aspergillus, Cladosporium, Wallemia, Mucor, and Rhizopus genera. Fungi were carried by particles of aerodynamic diameters, mainly between around 2.0 and 10.0 µm. The findings dealing with size distribution and biodiversity of bioaerosols suggest that employees are exposed to complex bioaerosols during their work and help to make a finer diagnosis of the risks involved, which is often difficult in the absence of any occupational exposure limit (OEL) value for bioaerosols in general.

Severe ozone (O3) pollution has been recorded in China in recent years. The key precursor, volatile organic compounds (VOCs), is still not well understood in Nanning, which is a less developed city compared to other megacities in China. In this study, a year-long measurement of VOCs was conducted from 1 October 2020 to 30 September 2021, to characterize the ambient variations and apportion the source contributions of VOCs. The daily-averaged concentration of VOCs was measured to be 26.4 ppb, ranging from 3.2 ppb to 136.2 ppb across the whole year. Alkanes and oxygenated VOCs (OVOCs) were major species, contributing 46.9% and 25.2% of total VOC concentrations, respectively. Propane, ethane, and ethanol were the most abundant in Nanning, which differed from the other significant species, such as toluene (3.7 ppb) in Guangzhou, ethylene (3.8 ppb) in Nanjing, and isopentane (5.5 ppb), in Chengdu. The positive matrix factorization (PMF) model resolved six source factors, including vehicular emission (contributing 33% of total VOCs), NG and LPG combustion (19%), fuel burning (17%), solvent use (16%), industry emission (10%), and biogenic emission (5%). This indicated that Nanning was less affected by industrial emission compared with other megacities of China, with industry contributing 12–50%. Ethylene, m/p-xylene, butane, propylene, and isoprene were key species determined by ozone formation potential (OFP) analysis, which should be priority-controlled. The variations in estimated OFP and observed O3 concentrations were significantly different, suggesting that VOC reactivity-based strategies as well as meteorological and NOx effects should be considered collectively in controlling O3 pollution. This study presents a year-long dataset of VOC measurements in Nanning, which gives valuable implications for VOC control in terms of key sources and reactive species and is also beneficial to the formulation of effective ozone control strategies in other less developed regions of China.

Results from air pollution exposure assessment studies suggest that ambient fine particles [particulate matter with aerodynamic diameter $\\leq 2.5 \\mu g (PM_{2.5})$], but not ambient gases, are strong proxies of corresponding personal exposures. For particles, the strength of the personal-ambient association can differ by particle component and level of home ventilation. For gases, however, such as ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2), the impact of home ventilation on personal-ambient associations is untested. We measured 24-hr personal exposures and corresponding ambient concentrations to PM2.5, sulfate (SO42-), elemental carbon, O3, NO2, and SO2 for 10 nonsmoking older adults in Steubenville, Ohio. We found strong associations between ambient particle concentrations and corresponding personal exposures. In contrast, although significant, most associations between ambient gases and their corresponding exposures had low slopes and R2 values; the personal-ambient NO2 association in the fall season was moderate. For both particles and gases, personal-ambient associations were highest for individuals spending most of their time in high- compared with low-ventilated environments. Cross-pollutant models indicated that ambient particle concentrations were much better surrogates for exposure to particles than to gases. With the exception of ambient NO2 in the fall, which showed moderate associations with personal exposures, ambient gases were poor proxies for both gas and particle exposures. In combination, our results suggest that a) ventilation may be an important modifier of the magnitude of effect in time-series health studies, and b) results from time-series health studies based on 24-hr ambient concentrations are more readily interpretable for particles than for gases.

Simulations of photosynthesis by terrestrial biosphere models typically need a specification of the maximum carboxylation rate (V cmax). Estimating this parameter using A–C i curves (net photosynthesis, A, vs intercellular CO2 concentration, C i) is laborious, which limits availability of V cmax data. However, many multispecies field datasets include net photosynthetic rate at saturating irradiance and at ambient atmospheric CO2 concentration (A sat) measurements, from which V cmax can be extracted using a ‘one-point method’. We used a global dataset of A–C i curves (564 species from 46 field sites, covering a range of plant functional types) to test the validity of an alternative approach to estimate V cmax from A sat via this ‘one-point method’. If leaf respiration during the day (R day) is known exactly, V cmax can be estimated with an r 2 value of 0.98 and a root-mean-squared error (RMSE) of 8.19 μmolm−2 s−1. However, R day typically must be estimated. Estimating R day as 1.5% of V cmax, we found that V cmax could be estimated with an r 2 of 0.95 and an RMSE of 17.1 μmolm−2 s−1. The one-point method provides a robust means to expand current databases of fieldmeasured V cmax, giving new potential to improve vegetation models and quantify the environmental drivers of V cmax variation.

The first extensive measurements of short-chain chlorinated paraffins (SCCPs) in the atmosphere of the Southern Hemisphere are presented. The analytical and sampling methodologies used in this Australian study were verified by systematic testing along with two inter-comparisons with Northern Hemisphere laboratories with established SCCP programs. In the ambient atmosphere of Melbourne, Australia, in 2013-14, there was a clear seasonal cycle in SCCP monthly averaged concentrations, these ranging from 28.4 ng m-3 in summer to 1.8 ng m-3 in winter. Air temperature was the factor most closely related to the seasonal cycle in SCCPs in Melbourne. The average SCCP concentrations observed indoors were less than those observed outdoors. Atmospheric concentrations of SCCPs in Melbourne are more than two orders of magnitude higher than concentrations in the background atmosphere. Surprisingly, the SCCP concentrations in Melbourne are similar to those observed in cities in Japan, South Korea and the United Kingdom, and less than those observed in China. Direct transport of SCCPs in the atmosphere from the Northern Hemisphere emissions to Melbourne is ruled out. Instead elevated concentrations in the Melbourne air-shed are most likely a result of the long-term import of SCCPs as industrial chemicals and within manufactured materials from the Northern Hemisphere so that the use of SCCPs in Melbourne and their consequent release to the environment has produced environmental reservoirs of SCCPs in Melbourne that are comparable with those in some Northern Hemisphere cities. The increase in SCCP concentrations from winter to summer is consistent with the temperature dependence of partitioning of SCCPs between the atmosphere and other reservoirs. Insufficient information exists on SCCP use and its presence in soils and sediments in Australia to indicate whether the atmospheric presence of SCCPs in Melbourne is a legacy issue due to its import and use as a metal cutting agent in past decades or due to ongoing imports of manufactured materials containing SCCPs today.

The Czech Hydrometeorological Institute (CHMI) estimated the transboundary transport of air pollution between the Czech Republic and Poland by assessing relationships between weather conditions and air pollution in the area as part of the \"Air Quality Information System in the Polish-Czech border of the Silesian and Moravian-Silesian region\" project (http://www.air-silesia.eu). Estimation of cross-border transport of pollutants is important for Czech-Polish negotiations and targeted measures for improving air quality. Direct measurement of PM and sulphur dioxide (SO ) concentrations and the direction and wind speed from measuring stations in the vicinity of the Czech-Polish state border in 2006-2012. Taking into account all the inaccuracies, simplifications and uncertainties, by which all of the measurements are affected, it is possible to state that the PM transboundary transport was greater from the direction of Poland to the Czech Republic, rather than the other way around. Nevertheless, the highest share of the overall PM concentration load was recorded on days with a vaguely estimated airflow direction. This usually included days with changing wind direction or days with a distinct wind change throughout the given day. A changeable wind is most common during low wind speeds. It can be assumed that during such days with an ambiguous daily airflow, the polluted air saturated with sources on both sides of the border moves from one country to the other. Therefore, we could roughly ascribe an equal level of these concentrations to both the Czech and Polish side. PM transboundary transport was higher from Poland to the Czech Republic than from the opposite direction, despite the predominant air flow from the Czech Republic to Poland.

When a non-climate institution, policy, or regulation corrects a pre-existing market failure that would be exacerbated by climate change, it may also incidentally induce climate adaptation. This regulation-induced adaptation can have large positive welfare effects. We develop a tractable analytical framework of a corrective regulation where the market failure interacts with climate, highlighting the mechanism of regulation-induced adaptation: reductions in the climate-exacerbated effects of pre-existing market failures. We demonstrate this empirically for the US from 1980 to 2013, showing that ambient ozone concentrations increase with rising temperatures, but that such increase is attenuated in counties that are out of attainment with the Clean Air Act’s ozone standards. Adaptation in nonattainment counties reduced the impact of a 1 °C increase in climate normal temperature on ozone concentration by 0.64 parts per billion, or about one-third of the total impact. Over half of that effect was induced by the standard, implying a regulation-induced welfare benefit of $412–471 million per year by mid-century under current warming projections.

An intensive particle monitoring study was conducted in homes in the Boston, Massachusetts, area during the winter and summer of 1996 in an effort to characterize sources of indoor particles. As part of this study, continuous particle size and mass concentration data were collected in four single-family homes, with each home monitored for one or two 6-day periods. Additionally, housing activity and air exchange rate data were collected. Cooking, cleaning, and the movement of people were identified as the most important indoor particle sources in these homes. These sources contributed significantly both to indoor concentrations (indoor-outdoor ratios varied between 2 and 33) and to altered indoor particle size distributions. Cooking, including broiling/baking, toasting, and barbecuing contributed primarily to particulate matter with physical diameters between 0.02 and 0.5 μm [ PM(0.02-0.5)], with volume median diameters of between 0.13 and 0.25 μm. Sources of particulate matter with aerodynamic diameters between 0.7 and 10 μm [ PM(0.7-10)] included sautéing, cleaning (vacuuming, dusting, and sweeping), and movement of people, with volume median diameters of between 3 and 4.3 μm. Frying was associated with particles from both PM(0.02-0.5) and PM(0.7-10). Air exchange rates ranged between 0.12 and 24.3 exchanges/hr and had significant impact on indoor particle levels and size distributions. Low air exchange rates (< 1 exchange/hr) resulted in longer air residence times and more time for particle concentrations from indoor sources to increase. When air exchange rates were higher (> 1 exchange/hr), the impact of indoor sources was less pronounced, as indoor particle concentrations tracked outdoor levels more closely.

This paper examines the effect of oxygen concentration on the oxidation process and properties of aluminum particles, providing valuable insights for production and storage. Micron-grade aluminum powders were tested at heating rates of 5, 7.5, 10, and 15 K/min under oxygen concentrations of 7, 11, 15, 21, and 30 vol%. Results indicate a two-step mass gain oxidation process, with less pronounced mass gain at lower oxygen concentrations. SEM and XRD characterized the morphological and crystalline changes during oxidation. Lowering oxygen concentration from 30 vol% to 7 vol% increased the onset oxidation temperature by 17.1 °C. Increasing the proportion of inert gas in the atmosphere increases the ignition temperature of aluminum powder. The mathematical modeling approach of AKTS was used to decouple and analyze the thermal effects of simultaneous melting and oxidation, using the Friedman method to show that the apparent activation energy is about 350 kJ/mol in low-oxygen atmospheres (7 vol% and 11 vol%). The kinetics of aluminum oxidation were found to be closely related to the oxygen concentration, and based on the kinetics parameter, it is possible to predict a minimum limiting oxygen concentration.

This study evaluated the reliability of an electronic nose in monitoring odour concentration near a wastewater treatment plant and examined the correlation between four sensor readings and odour intensity. The electronic nose chemical sensors are related to the concentration of the following chemical species: two values for the concentration of VOCs recorded via the PID sensor (VPID) and the EC sensor (VEC), and concentrations of sulfuric acid (VH2S) and benzene (VC6H6). Using Random Forest and least squares regression analysis, the study identifies VH2S and VC6H6 as key contributors to odour concentration (CcOD). Three Random Forest models (RF0, RF1, RF2), with different characteristics for splitting between the test set and the training set, were tested, with RF1 showing superior predictive performance due to its training approach. All models highlighted VH2S and VC6H6 as significant predictors, while VPID and VEC had less influence. A significant correlation between odour concentration and specific chemical sensor readings was found, particularly for VH2S and VC6H6. However, predicting odour concentrations below 1000 ouE/m3 proved challenging. Linear regression further confirmed the importance of VH2S and VC6H6, with a moderate R-squared value of 0.70, explaining 70% of the variability in odour concentration. The study demonstrated the effectiveness of combining Random Forest and least squares regression for robust and interpretable results. Future research should focus on expanding the dataset and incorporating additional variables to enhance model accuracy. The findings underscore the necessity of specific sensor training and standardised procedures for accurate odour monitoring and characterisation.