Odour annoyance and physical symptoms among residents living near waste treatment centres

The screening evaluation of environmental odors: a new dispersion modelling-based tool

Odor pollution is the biggest source of complaints from citizens concerning environmental issues after noise. Often, the need for corrective actions is evaluated through simulations performed with atmospheric dispersion models. To save resources, air pollution control institutions perform a first-level odor impact assessment, for screening purposes. This is often based on Gaussian dispersion models (GDM), which does not need high computational power. However, their outputs tend to be conservative regarding the analyzed situation, rather than representative of the real in-site conditions. Hence, regulations and guidelines adopted at an institutional level for authorization/control purposes are based on Lagrangian particle dispersion models (LPDM). These models grant a more accurate simulation of the pollutants' dispersion even if they are more demanding regarding both technical skills and computing power. The present study aims to increase the accuracy of screening odor impact assessment by identifying the correlation function of the outputs derived from the two simulation models. The case study is placed in northern Italy, where a single-point source, with various stack heights, was considered. The case study is placed in northern Italy, where a single-point source, with various stack heights, was considered. The obtained correlation functions allow the practitioner to have a more accurate first-level odor impact assessment, to save time for training, and to reduce the site-specific meteorological data before proceeding with the simulation. The identified functions could allow institutions to estimate the results that would have been forecasted with the application of the more complex LPDM, applying, however, the much simpler GDM. This solution grants an accurate tool which can be used to address citizens' concerns while saving workforce and technical resources. Limitations are related to the specificity of the method regarding type sources, orography, and meteorological conditions. Comparison with other screening tools is also presented and discussed.

New circularity indicator for decision making in the stockpile management of construction and demolition waste: Perspectives of Australian practitioners

Despite the increasing popularity of the circular economy, there remains a lack of consensus on how to quantify circularity, a critical aspect of the practical implementation of this model. To address this gap, this article examines the industry's perspective and efforts toward implementing the circular economy in real-world scenarios. We conducted 40 interviews with engineers, project leaders, and top-level managers in the Australian construction sector. Using Saldaña's coding approach, we analysed their views on circular economy practices and efforts within their organisations. Our findings reveal while waste minimisation, reduction of greenhouse gas emissions, and cost considerations are widely regarded as essential indicators of a successful circular economy model, the significance of waste storage and long-term stockpiling while awaiting treatment has been overlooked or under-emphasised in industry practices and academic literature. Stockpiling of waste has often been seen as a staging process in waste treatment. However, based on industry insights, it accumulates to the point of mismanagement when it becomes a safety and environmental concern. Addressing this oversight, we propose a storage circularity indicator that allows incorporating waste storage and stockpiling in circular economy models. Our research contributes to various environmental and waste management aspects, supporting policies and strategies for solid waste management and excessive stockpile prevention. By emphasising the significance of storage circularity, we clarify waste prevention techniques and address socio-economic issues such as the urgent need to reduce long-term stockpiling of solid waste. This work highlights the importance of decision-support tools in waste management to facilitate the implementation of circular economy principles. Our proposed storage circularity indicator promotes industrial collaboration, aligning with the concept of industrial symbiosis to optimise resource use and minimise waste generation. By discussing these topics, we aim to contribute to the advancement of more robust waste management strategies and policies that promote sustainable production and consumption practices.

Application of Sensory Methods to Evaluate the Effectiveness of Solutions to Reduce the Exposure to Odour Nuisance and Ammonia Emissions from the Compost Heaps

Exposure to high concentrations of odours can result in health effects associated with direct health risks and irritation from nuisance. This investigation aimed to correlate aspects of the waste composting process with the emission levels of malodourous compounds. An essential optimisation criterion is the reduction of negative environmental impacts, particularly odour emissions. This study characterises odour concentration variations across various technological variants over different weeks of the composting process. A secondary objective is evaluating the efficacy of these variants, which differ in inoculation substances and compost heap composition. Olfactometric analyses were conducted using portable field olfactometers, enabling precise dilutions by mixing contaminated and purified air. The primary aim was to examine the correlation between selected odour parameters, determined via sensory analysis, and ammonia concentration during different composting weeks. Ammonia levels were measured using an RAE electrochemical sensor. Research shows that odour concentration is a significant indicator of compost maturity. In situ, olfactometric testing can effectively monitor the aerobic stabilisation process alone or with other methods. The most effective technological solution was identified by combining olfactometric and ammonia measurements and monitoring composting parameters, ensuring minimal odour emissions and the safety of employees and nearby residents.

Real-Time Monitoring of Odour Emissions at the Fenceline of a Waste Treatment Plant by Instrumental Odour Monitoring Systems: Focus on Training Methods

Waste treatment plants (WTPs) often generate odours that may cause nuisance to citizens living nearby. In general, people are becoming more sensitive to environmental issues, and particularly to odour pollution. Instrumental Odour Monitoring Systems (IOMSs) represent an emerging tool for continuous odour measurement and real-time identification of odour peaks, which can provide useful information about the process operation and indicate the occurrence of anomalous conditions likely to cause odour events in the surrounding territories. This paper describes the implementation of two IOMSs at the fenceline of a WTP, focusing on the definition of a specific experimental protocol and data processing procedure for dealing with the interferences of humidity and temperature affecting sensors' responses. Different approaches for data processing were compared and the optimal one was selected based on field performance testing. The humidity compensation model developed proved to be effective, bringing the IOMS classification accuracy above 95%. Also, the adoption of a class-specific regression model compared to a global regression model resulted in an odour quantification capability comparable with those of the reference method (i.e., dynamic olfactometry). Lastly, the validated models were used to process the monitoring data over a period of about one year.

Emission and spatial variation characteristics of odorous pollutants in the aerobic tank of an underground wastewater treatment plant (UWWTP) in southern China

In this study, the spatial concentration of odorous pollutants in the aerobic tank of an underground wastewater treatment plant (UWWTP) in southern China is monitored. The odour activity value, odour contribution rate, and chemical concentration contribution rate are used to evaluate the degree of contribution of odorous substances. Computational fluid dynamics (CFD) simulations of odorous pollutant diffusion are also established. The study shows that the odorous substances detected in the aerobic tank mainly included ammonia (NH3), hydrogen sulfide (H2S), trimethylamine (C3H9N), and methanethiol (CH3SH), and their concentrations are 1.160, 0.778, 0.022, and 0.0006 mg/m3, respectively. The total odour activity value of the aerobic tank is 450.72 (dimensionless), of which the odour activity value of H2S is 432.22, and the contribution rate reaches 95.9%. H2S is the main contributor to odour and a key controlled substance. The air inlets and exhaust outlets in the aerobic tank are cross-arranged at the top of the space, and the CFD model of odorous pollutant diffusion shows that the gas flow organization determines the odorous pollutant diffusion. The spatial distribution of gas flow and odorous substances in the aerobic tank is relatively uniform, and the odour collection efficiency is higher. The production flux and production coefficient of H2S in the aerobic tank are calculated as 25.831 mg/(m2·h) and 14.149 mg/t, respectively. This study determines the reasonable air supply and exhaust design of the aerobic tank, the number of odour pollutants, and the key controlled substances. These findings offer guidance and serve as useful references for the prevention and control of odour pollution in aerobic tanks of the same type of UWWTPs.

Odor generation pattern of swine manure according to the processing form of feed

Feed has a great influence on the composition of swine manure, which is the principal cause of odor. Therefore, the purpose of this study is to simply change the shape of pig feed and control calories to find a suitable feed form for reducing the smell of swine manure. The experiment was conducted on 15 pigs from July to August 2021, and a total of three measurements were done. Three types of feed were evaluated in this study. The analysis items related to odor of swine manure are complex odor, ammonia, sulfur-based odors, and volatile organic compounds (VOCs). In the case of complex odor, dilution multiples tended to decrease over time, except for type A feed. The concentration of ammonia in all types of feed decreased over time. Most sulfur-based odorous substances except hydrogen sulfide at the first measurement were not detected. Representatively, Decane, 2,6-Dimethylnonane, and 1-Methyl-3-propylcycolhexane were detected in VOCs generated from swine manure. The major odorous substansces in swine manure have changed from ammonia and sulfur compounds to VOCs. In order to reduce the odor caused by swine manure, it is ad-vantageous to use low-calorie feed consisting of pellet-type.

Multi-dimension analysis of volatile sulfur compound emissions from an urban wastewater treatment plant

Long-term monitoring of volatile sulfur compounds (VSCs) released at the water-air interface from different treatment units of an anaerobic/oxic (A/O) wastewater treatment plant (WWTP) was carried out to assess the temporal and spatial emission characteristics of VSCs, to explore relationships between wastewater quality and VSC release. The VSC from non-aerated and aerated units were collected using dynamic and static chambers, respectively, and determined using gas chromatography. The VSC emission fluxes diminished in the order of primary sedimentation tank (PST) > anaerobic areas (ANA) > oxic section 1 (OX1). VSCs were not detected in the oxic section 2 (OX2), the oxic areas section 3 (OX3), and the final setting basin (FSB). Release capacities of VSCs descended in the order of summer > fall > spring > winter, with July, August, and September being the months with the highest VSC release capacities. VSC emission fluxes correlated well with wastewater temperatures, sulfate concentrations, and COD. VSC emission flux empirical equations based on wastewater temperature, sulfate concentrations, and COD were established. Based on the established VSC emission empirical equation, a control strategy to reduce the operating costs of deodorization facilities was proposed. This strategy is economically efficient and reduces the consumption of electrical energy.

The Association between Perceived Annoyances in the Indoor Home Environment and Respiratory Infections: A Danish Cohort Study with up to 19 Years of Follow-Up

The increasing prevalence of reported annoyances in the indoor environment threatens public health. This study aimed to investigate the association between perceived annoyances from the home environment and respiratory infections among individuals with and without asthma or chronic obstructive pulmonary disease (COPD). A total of 16,688 individuals from the Danish Health and Morbidity Survey initiated in 2000 were grouped according to their patterns of perceived annoyances. Information on respiratory infections (all causes, bacterial, viral, and those leading to hospital admissions) was obtained from Danish registers up to 19 years after the survey. Poisson regression of incidence rates (IRs) was applied to estimate incidence rate ratios (IRRs). Annoyances significantly increased the IR for respiratory infections of all causes and bacterial respiratory infections in individuals without asthma or COPD, adjusted IRR 1.16 (95% CI: 1.01, 1.34) and 1.15 (95% CI: 1.02, 1.31), respectively. However, no difference was observed for viral respiratory infections nor hospital admissions. Individuals with asthma or COPD and a high level of annoyances had a non-significantly increased IR in all four analyses of respiratory infections. These findings provide support for perceived annoyances as an important risk factor for respiratory infections.

Assessment of gas dispersion near an operating landfill treated by different intermediate covers with soil alone, low-density polyethylene (LLDPE), or ethylene vinyl alcohol (EVOH) geomembrane

This study evaluated the impact area of odiferous gas (i.e., H₂S) dispersion near an operating landfill installed with three different intermediate covers, including soil alone, linear low-density polyethylene (LLDPE), or ethylene vinyl alcohol (EVOH) geomembrane (GM). By using the finite element method employing Reynolds-averaged Navier-Stokes and Fick's Law coupled equations, the performance of the different cover cases for reducing odor dispersion was comparatively evaluated considering environmental factors, including topographic, meteorology, and gas emission. The odor dispersion patterns and the size of affected residents were analyzed for the twelve different scenarios varied with the cover type and seasonal variation. According to the results, it was found that the wind speed affected the time of odor dispersions more with the relatively flat terrain conditions around the landfill but barely affected the size of the dispersion area. Moreover, it was found that the higher concentration (100 ppb) of odor gas is mainly located within a 5.0-km distance from the landfill. Among four seasons, the odor covers the largest area in summer, which is mainly due to the landfill producing more odor gas and giving a higher source concentration in summer. The gas dispersion simulation for different covers showed that the type of covering layer significantly affects the impact area boundary of gas odor. The results showed that the odor area of the LLDPE GM cover case is 1.3% of soil alone case, and the case of EVOH GM is 14.5% of LLDPE GM case. At the same time, the number of residents that may be affected by the odor of the LLDPE GM case and EVOH GM case is 4.81% and 0.63% of soil alone case, respectively.

Experimental evaluation on liquid area sources: Influence of wind velocity and temperature on the wind tunnel sampling of VOCs emissions from wastewater treatment plants

The investigation of Volatile Organic Compounds (VOCs) emission from wastewater basins is a challenging issue. In particular, the quantification of an accurate emission rate appears quite tricky, since the release of VOC compounds from this type of source, and the subsequent dispersion into the atmosphere, is ruled by different complex phenomena, potentially affected by a variety of external chemical and physical parameters. In this regard, the wind velocity and the liquid temperature represent variables that are worth investigating. Given this, the present paper discusses an experimental study aimed at evaluating the influence of these variables on the emission rate of VOCs (i.e. acetone, toluene and butanol) in solution with water at low concentrations (0.5 mL/L and 5 mL/L). The experimental trials are conducted using a wind tunnel system, changing the sweep air flow from 0.02 m/s to about 0.06 m/s and the liquid temperature from 20 °C to 35 °C. This study reveals that while the wind velocity seems to slightly influence the emission rate of VOCs estimated by wind tunnel sampling, the effect of the temperature appears much more significant. This behaviour is also confirmed by experimental trials conducted on real-case industrial wastewater, coming from an equalization tank. In view of this, the approach commonly applied to evaluate the influence of wind velocity (i.e. a dependence of the odour emission rate on the square root of the wind velocity) appears not fully consistent with the experimental results obtained at low concentrations by wind tunnel sampling. Also, the influence of temperature seems more pronounced in the case of butanol, in accordance with the theoretical trend of Henry constant as a function of temperature.

Assessing the health risk of living near composting facilities on lung health, fungal and bacterial disease in cystic fibrosis: a UK CF Registry study

AIM

To explore the health risk of living near permitted composting sites (PCSs) on disease severity in children and adults with cystic fibrosis (CF) across the UK.  METHODS: A semi-individual cross-sectional study was used to examine the risk of disease severity in people with CF (pwCF) within and beyond 4 km of PCSs in the UK in 2016. All pwCF registered in the UK CF Registry were eligible for this study. Linear and Poisson regressions, adjusted for age, gender, genotype, BMI, Pseudomonas aeruginosa and deprivation, were used to quantify associations between distance to a PCS and percent predicted forced expiratory volume in one second (ppFEV₁), pulmonary exacerbations (#IVdays), and fungal and bacterial infections.

RESULTS

The mean age of the 9,361 pwCF (3,931 children and 5,430 adults) studied was 20.1 (SD = 14.1) years; 53.3% were male; and 49.2% were homozygous F508del. Over 10% of pwCF (n = 1,015) lived within 4 km of a PCS. We found no statistically significant difference in ppFEV₁ and #IVdays/year in children. However, in adults, ppFEV₁ was -1.07% lower (95% confidence interval (CI): -2.29%, 0.16%) and #IVdays/year were 1.02 day higher (95%CI: 1.01, 1.04) within 4 km of a PCS. Furthermore, there were statistically significant differences in mean ppFEV₁ in CF adults with Aspergillus fumigatus (58.2.% vs 62.0%, p = 0.005) and Candida spp. (56.9% vs 59.9%, p = 0.029) residing within 4 km of a PCS. No associations were identified for allergic bronchopulmonary aspergillosis, P. aeruginosa or Staphylococcus aureus.

CONCLUSIONS

This novel national study provides evidence that adults with CF living near a PCS may experience small reductions in lung function, an increased risk of pulmonary exacerbations, and more frequent fungal infections. If confirmed by studies using refined exposure assessment methods accounting for bioaerosol dispersion, these results could have important implications for the living environment of pwCF.

Comparative analysis of very volatile organic compounds and odors released from decorative medium density fiberboard using gas chromatography-mass spectrometry and olfactory detection

VVOCs with a retention range below C₆ have become one of the main indoor pollutants that negatively affect human health. Most studies have focused on the emission of VOCs from furniture and decorative materials, seldom consider VVOCs. To close this gap, a 15-L environmental chamber, combined with multi-absorbent tube, was used for gas sampling. Emissions of VVOCs and odors released from decorative medium density fiberboard (MDF) were measured using gas chromatography-mass spectrometry and olfactometry detection. The results demonstrated that multi-absorbent tubes had excellent capture capacity for low-molecular-weight VVOCs. Thickness and decorative materials had conspicuous effects on VVOCs and odor emissions. The total VVOCs (TVVOC) from 18-mm decorative MDF was consistently higher than that of 8-mm samples. The major VVOCs from these decorative MDF were alcohols, esters and ketones, which were the major odor contributors with high odor intensity values. VVOCs concentration generally increased as thickness increased, but it decreased after decorative treatment. Fruity and alcohol-like were the main odor impressions of 8-mm MDF, whereas sweet and fruity were the major odor impressions of 8-mm polyvinyl chloride decorative MDF (PVC-MDF) and melamine impregnated paper decorative MDF (MI-MDF). Fruity was the main odor impression of 18-mm decorative MDF. The overall odor intensity increased and the major odor impression may differ when thickness was changed. Both the MI and the PVC decorative materials blocked some odor emissions but did so to a greater extent with the former than with the latter. Identification and analysis of the composition of VVOCs can supplement a database structure network of volatile pollutants and establish a novel and feasible method to investigate low-molecular-weight substances from wooden materials and their products.

Citizens' perception towards landfill exposure and its associated health effects: a PLS-SEM based modeling approach

Around 90% of municipal solid waste in India is treated improperly at open dumps and landfills, posing a severe threat to public health. Landfills are an annoyance whose presence causes uncertainty, stress, and dissatisfaction in neighboring residential areas. This research investigates the perceived impact of exposure to landfills on health in terms of environmental quality, general living status, and defensiveness. To meet the current study's objective, "Case of exposed population" to landfill, i.e., 384 participants dwelling near 1 km of the dump site in Siliguri municipality, West Bengal, India, were considered using a purposive sample approach. The present study adopted Partial Least Square-Structural Equation Modeling (PLS-SEM) approach to prove the hypothesis related to the residential perception of landfills and their impact on health. The findings reveal that all three constructs, namely environmental quality (β = .997, t = 19.607, and ρ < 0.001), general life status (β = .116, t = 2.475 and ρ < 0.05), and people's defensive attitude (β = .150, t = 2.526 and ρ < 0.001), significantly affect the health condition of those exposed to a landfill site. The results suggest that by understanding the impact of landfills on resident health, policymakers and bureaucrats can promote reliable and effective measures linked to sustainable solid waste disposal facilities. The administration must create a policy to protect citizens who live near landfills by improving the ambient environment, establishing health management facilities, and raising awareness through public participation.

Spatiotemporal footprints of odor compounds in megacity's food waste streams and policy implication

Odor pollution is one of the most critical issues in food waste (FW) recycling and has significant implications for human health. However, knowledge of their occurrence and spatiotemporally dynamic in urban FW streams is limited, making it not conducive to implement targeted odor management. This work followed the occurrence of 81 odor compounds (OCs) in nine FW-air environments along the Shanghai's FW streams for one year. Results showed that NH₃, acetic acid, acetaldehyde, acetone, 2-butanone, and methylene chloride were consistently the predominant OCs, despite the distinct differences in OCs profiles across seasons and treatment sites. Ridge regression and principal coordinate analysis demonstrated that seasons might play a non-negligible role in shaping odor profiles, and ambient temperature and humidity could account for the seasonal variation in OCs levels. Based on the modified fuzzy synthetic evaluation system, the screened priority pollutants in different FW-air environments were found broadly similar and the regulated air pollutants released via FW should be expanded to aldehyde and ketone compounds, especially for acetaldehyde. To our knowledge, this study is the first to track the spatiotemporal footprints of OCs within urban FW streams, and provides new insights into the control policy on FW-derived odor issues for megacities.

A New Perspective of Sustainable Perception: Research on the Smellscape of Urban Block Space

The smell of space is inseparable from the sustainable development of the living environment. The research on olfactory perception and smell landscape has a positive effect on landscape design and urban planning and contributes to the formation and design optimization of unique urban memory. This study combines urban smell tracking experiments with Internet social media data analysis to classify smells in the old city center of Guangzhou, China, and analyzes the study within the inner ring and six historic districts. Based on the research results, the smell map was drawn, and the reliability of the smell map was tested through social data and semantic analysis. The emotional score heat map of smell and emotion in six regions was constructed, highlighting the impact of smell in key neighborhoods on the environment. In the conclusion to the study, the thematic routes of green urban design are proposed: sightseeing routes, cultural routes, and food routes, as well as improvement strategies to promote the integration of smell and urban operation activities and the sustainable development of urban regional characteristics.

Research on Very Volatile Organic Compounds and Odors from Veneered Medium Density Fiberboard Coated with Water-Based Lacquers

Very volatile organic compounds (VVOCs) are a group of important odor pollutants affecting indoor air quality that have been shown to be harmful to human health. A 15 L environmental chamber, combined with multi-bed tube was used to collect gases. Fifteen very volatile organic compounds (VVOCs), including 12 odor compounds, were identified from veneered medium density fiberboard coated with water-based lacquer (WB-MDF) using gas chromatography–mass spectrometry/olfactometry (GC-MS/O). The total very volatile organic compound (TVVOC) and total odor intensity (TOI) showed a decreasing trend over time, reaching equilibrium on day 28. TVVOC showed an overall slow-fast-slow emission profile, from day 3 to day 7, with a maximum decay rate of 29.7%. TOI showed the greatest rate of decline from day 1 to day 3, at approximately 12%. Alkane and alcohol VVOCs were the more abundant compounds, accounting for at least 60% and even up to 80% of the total. The major odor impression was fruity, with a highest odor rating of 6.6, followed by sweet, with an odor rating of 6.1. Although the odor impression changed from sweet to fruity over time, it seemed pleasant overall. The odor contributors were mainly alkanes, alcohols, esters, and ethers, which had relatively high odor intensities. The main odor-contributing substances were dichloromethane, ethanol, ethyl acetate, 2-methylacrylic acid methyl ester, and tetrahydrofuran. When WB-MDF is used for furniture or other decorative materials, it is strongly recommended that it be stored under ventilation for at least 28 days and the adoption of substitute solvents of lacquers, modified adhesives, and low-odor wood raw materials is recommended. These possible initiatives would contribute to the aim of building an environmentally friendly indoor environment.

Odor perception and symptoms during acrolein exposure in individuals with and without building-related symptoms

Building-related symptoms (BRS) is a significant work-related and public health problem, characterized by non-specific symptoms occurring in a particular building. The cause of BRS is unknown, but certain reactive compounds are suggested risk factors. The aim of this controlled exposure study was to investigate whether BRS cases report more odor annoyance and symptoms and show altered autonomous nervous system (ANS) response during exposure to the reactive aldehyde, acrolein in comparison with referents. Individuals with BRS (n = 18) and referents (n = 14) took part in two exposure sessions (80 min). One session contained heptane alone, and the other heptane and acrolein. Perceived odor annoyance; eye, nose, and throat symptoms; and ANS response were measured continuously. BRS cases did not experience more odor annoyance; eye, nose, and throat symptoms; or altered ANS response in comparison with referents during the exposures. Supplementary analyses revealed that BRS cases that also reported chemical intolerance perceived more symptoms than referents during acrolein exposure. Acrolein exposure at a concentration below previously reported sensory irritation detection thresholds is perceived as more irritating by a subgroup of BRS individuals compared with referents. The results of this study indicate that a subset of individuals with building related symptoms (BRS) has a lowered sensory irritation threshold towards acrolein exposure. Future guidelines on chemical exposures to acrolein should take time and individual sensitivity into account.

Development and application of high resolution mass spectrometry analytical method to study and identify the photoinduced transformation products of environmental pollutants

Terpenes are among the major causes of pleasant or unpleasant odors close to active or inactive landfills. We studied R-limonene and p-cymene environmental degradation products using the heterogeneous photocatalysis mediated by titanium dioxide to explore the odor pollution. The aim of the study was the development of mass spectrometry based methods both hyphenated with GC and HPLC to identify and characterize transformation products (TPs) derived from photodegradation of R-limonene and p-cymene. With the GC-MS method we identified three TPs for R-limonene and two for p-cymene comparing the obtained mass spectra with those in the NIST library. While with HPLC-MS method, thanks to the use of the high resolution of MS tool, we recognized four and five TPs for R-limonene and p-cymene respectively. No p-cymene was detected as R-limonene transformation product. The methods developed were then applied to real environmental samples coming from landfills active (Lan1) or inactive (Lan2 and Lan3) located in northern Italy. R-limonene was detected in the active landfill (Lan1 at the concentration of 2.35 μg/mL) together with one of its TPs and one TP derived from p-cymene. p-Cymene was detected in the other two inactive landfills (Lan2 and Lan3 concentrations 0.025 and 0.15 μg/mL, respectively) together with one of its TP and two TPs coming from R-limonene photodegradation. The finding of TPs together with R-limonene and p-cymene both in active and inactive landfills point out the attention on the reduction of these molecules in the environment to reduce pollution and human risks.

Effects of environmental conditions on the emission and odor-active compounds from Fraxinus mandshurica Rupr

Being one of the most common wood in furniture and decoration, Fraxinus mandshurica Rupr. (F. mandshurica) is a frequently used material for wood products. However, the resulting odor problem has not yet been solved so far. Thus, this study focused on exploring odor-active compounds and investigating the effect of environmental conditions on emission and odor attributes. F. mandshurica was studied via TD-GC-MS/O combined with microchamber. Totally, 15 kinds of key odor-active compounds were detected from F. mandshurica. The main odorous components were found to be aromatics, aldehydes and ketones, esters, alcohols and acids. Six kinds of attributes played a key role in the overall odor character of F. mandshurica. Fragrant was the predominant odor impressions, followed by vinegar and antiseptic solution. The proportion of the odor-active compounds concentration to total concentration decreased with an increase in the temperature and relative humidity, while the ratio of air exchange rate to the loading factor had little effect on this. The total concentration of F. mandshurica increased as the temperature and relative humidity increased, but these decreased as the ratio of air exchange rate to the loading factor increased, while the total odor intensity reduced with the rise in the ratio of air exchange rate to the loading factor. Time was found to be the most effective factor for eliminating emissions. Considering the environmental conditions in this study, 40 °C, 60% relative humidity and a 1.0 m³·m^-2 h^-1 ratio of air exchange rate to loading factor are recommended to accelerate the emission of F. mandshurica. The optimum condition was found to be higher temperature, higher relative humidity and higher ratio of air exchange rate to loading factor.

Odor emissions: A public health concern for health risk perception

The olfactory nuisance, due to the emissions of active molecules, is mainly associated with unproperly managed waste disposal and animal farming. Volatile compounds e.g., aromatics, organic and inorganic sulfide compounds, as well as nitrogen and halogenated compounds are the major contributor to odor pollution generated by waste management plants; the most important source of atmospheric ammonia is produced by livestock farming. Although an odorous compound may represent a nuisance rather than a health risk, long-term exposure to a mixture of volatile compounds may represent a risk for different diseases, including asthma, atopic dermatitis, and neurologic damage. Workers and communities living close to odor-producing facilities result directly exposed to irritant air pollutants through inhalation and for this reason the cumulative health risk assessment is recommended. Health effects are related to the concentration and exposure duration to the odorants, as well as to their irritant potency and/or biotransformation in hazardous metabolites. The health effects of a single chemical are well known, while the interactions between molecules with different functional groups have still to be extensively studied. Odor emissions are often due to airborne pollutants at levels below the established toxicity thresholds. The relationship between odor and toxicity does not always occurs but depends on the specific kind of pollutant involved. Indeed, some toxic agents does not induce odor nuisance while untoxic agents do. Accordingly, the relationship between toxicity and odor nuisance should be always analyzed in detail evaluating on the characteristics of the airborne mixture and the type of the source involved.

A Heuristic Method for Modeling Odor Emissions from Open Roof Rectangular Tanks

This paper presents heuristic equations for estimating odor emissions from open-roof rectangular tanks as a function of the tank orientation, wind direction, wind speed and distance of the emitting surface from the tank top. These types of equations are important because they may help to improve emission calculations to avoid overestimations, which are damaging to the plant owner, and underestimations, which are negative for the population around the plant. Odor emissions were determined for four tanks with the same area, different shape factors and two different orientations and then used as inputs for a dispersion model in order to calculate separation distances and evaluate their differences. The results show that different separation distances were obtained depending on the tank orientation, shape factor and level of filling. Future field applications to verify and improve the proposed equations are desirable. If the effect of the tank orientation on odor emission is proven, the design of future industrial plants containing open-roof rectangular tanks should consider the results of detailed wind data analysis.

Artificial neural network (ANN) modeling for the prediction of odor emission rates from landfill working surface

Landfills release significant odorous compounds from the working surface, and their emission rates are crucial for odor and health risk assessment. A total of 99 valid datasets of odor emissions from a landfill working surface were obtained from in situ monitoring for 9 months. Meteorological parameters (temperature, humidity, atmospheric pressure) and waste properties (contents of protein, lipid, carbohydrate, ash, and moisture) were used to construct artificial neural network (ANN) models for the emission rate prediction of typical compounds. The optimal structures and performance of the ANN models were determined by comparing and training with different structural configurations. The ANN models with genetic algorithm (GA) optimization show better performance than those without GA. With the data distribution of input parameters, the ranges of the emission rates of typical compounds were predicted by combining the established ANN models and the Monte Carlo approach. The sensitivity and uncertainty analyses revealed that temperature, atmospheric pressure, protein and lipid contents are parameters sensitive to emission rates, and meteorological parameters have significant impacts on the uncertainty. The established ANN models for the prediction of emission rates can provide scientific evidence and an approach to assess and control the odor and health risk in waste sectors.

A review of environmental odor quantification and qualification methods: The question of objectivity in sensory analysis

For several years, various issues have up surged linked to odor nuisances with impacts on health and economic concerns. As awareness grew, recent development in instrumental techniques and sensorial analysis have emerged offering efficient and complementary approaches regarding environmental odor monitoring and control. While chemical analysis faces several obstacles, the sensory approach can help overcome them. Therefore, this latter may be considered as subjective, putting the reliability of the studies at risk. This paper is a review of the most commonly sensory methodology used for quantitative and qualitative environmental assessment of odor intensity (OI), odor concentration (OC), odor nature (ON) and hedonic tone (HT). For each of these odor dimensions, the assessment techniques are presented and compared: panel characteristics are discussed; laboratory and field studies are considered and the objectivity of the results is debated. For odor quantification, the use of a reference scale for OI assessment offers less subjectivity than other techniques but at the expense of ease-of-use. For OC assessment, the use of dynamic olfactometry was shown to be the least biased. For odor qualification, the ON description was less subjective when a reference-based lexicon was used but at the expense of simplicity, cost, and lesser panel-training requirements. Only when assessing HT was subjectivity an accepted feature because it reflects the impacted communities' acceptance of odorous emissions. For all discussed dimensions, field studies were shown to be the least biased due to the absence of air sampling, except for OC, where the dispersion modeling approach also showed great potential. In conclusion, this paper offers the reader a guide for environmental odor sensory analysis with the capacity to choose among different methods depending on the study nature, expectations, and capacities.

Industrial odour pollution and human health: a systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review to evaluate the association between residential or occupational short- and long-term exposure to odour pollution from industrial sources and the health status of the exposed population.

METHODS

The searches were conducted in Medline, EMBASE and Scopus in April 2021. Exposure to an environmental odour from industrial sources in population resident near the source or in workers was considered. We considered outcomes for which there was a biological plausibility, such as wheezing and asthma, cough, headache, nausea and vomiting (primary outcomes). We also included stress-related symptoms and novel outcomes (e.g. mood states). Risk of bias was evaluated using the OHAT tool. For primary outcomes, when at least 3 studies provided effect estimates by comparing exposed subjects versus not exposed, we pooled the study-specific estimates of odour-related effect using random effects models. Heterogeneity was evaluated with Higgins I2.

RESULTS

Thirty studies were eligible for this review, mainly cross-sectional (n = 23). Only one study involved school-age children and two studies involved workers. Only five studies reported odour effects on objective laboratory or clinical outcomes. Animal Feeding Operations and waste were the most common industrial sources. The overall odds ratios in exposed versus not exposed population were 1.15 (95% CI 1.01 to 1.29) for headache (7 studies), 1.09 (95% CI 0.88 to 1.30) for nausea/vomiting (7 studies), and 1.27 (95% CI 1.10 to 1.44) for cough/phlegm (5 studies). Heterogeneity was a moderate concern. Overall, the body of evidence was affected by a definitely high risk of bias in exposure and outcome assessment since most studies used self-reported information.

CONCLUSIONS

Findings underline the public health importance of odour pollution for population living nearby industrial odour sources. The limited evidence for most outcomes supports the need for high quality epidemiological studies on the association between odour pollution and its effects on human health.

Objective odor analysis of incidentally emitted compounds using the Langage des Nez® method: application to the industrial zone of Le Havre

Environmental odor studies are usually done using two approaches: nuisance impact assessment and source identification. The latter may be done using chemical analysis or sensory analysis. While sensory analyses offer many advantages, they also face the main obstacle: odor nature description still uses conventional methods based on subjective evocations as odor descriptors. This makes the sensory method ineffective especially when the expected outcome is the source identification in the context of an industrial accident. This work wants to fulfill this gap proposing to build an objective database including the odor nature description of selected potentially emitted compounds using a promising approach: the Langage des Nez® (LdN). Using definite odorous compounds as odor referents, this work provides the odor nature description of 44 compounds, reported as potential incidentally released chemical compounds in the industrial zone of Le Havre. The city of Le Havre, France, was chosen as a model due to a history of odorous emissions of industrial origins. A trained panel described the odor of each compound using up to three referents of the LdN referents collection and attributed a score to each referent. A data analysis method was developed based on the frequency of citation of the referents and the attributed scores allowing the categorization of each compound in three types of consensus categories. The data analysis results showed that around 80% of compounds were described with a good consensus, showing the LdN as a well-adapted lexicon. This study does not point to any correlation between the chemical structures of the compounds of interest and their relative referents. When compared to conventional methods, LdN revealed a more objective and precise approach. The proposed experimental method and the results provided in this work offer the first insight for time-efficient approaches to objectively describe environmental odors, especially potentially emitted odors during incidents. This work may be supplemented by abatement and mixture effect investigations for a complete understanding of odor dispersion.

Environmental Odour Nuisance Assessment in Urbanized Area: Analysis and Comparison of Different and Integrated Approaches

Prolonged exposure to odour emissions causes annoyance which leads to nuisance and consequently to complaints. Different methodologies exist in the literature to evaluate odour impacts, but not all are suitable to assess environmental odour nuisance. Information about their applicability criteria and comparison, is scarce and referred to short time analysis. The research presents and discusses the application of different methods to characterize and assess odour nuisance around an industrial plant localized in a sensitive area. Experimental activities are carried out through a long-time analysis programme. Field inspections and predictive methods are investigated and compared. A modification of the traditional dispersion modelling approach is proposed in order to adapt its application for the prediction of the odour nuisance. The offensiveness and location factors are identified as key parameters in the quantification of the perceived nuisance. The integrated dispersion modelling multi-level approach is highlighted as the most suitable for defining the plant strategies. The paper provides useful information to characterize environmental odour problems and identify appropriate solutions for an effective management of odorous sources, with the aim of reducing complaints, restoring the proper relationship between odorous plants and the surrounding communities and increasing the overall quality of the environment.

Lung tissue inflammatory response and pneumonocyte apoptosis of Sprague-Dawley rats after a 30-day exposure in methyl mercaptan vapor

The objective of the research was to reveal the potential toxicity effects of methyl mercaptan on rat lung tissue. A dynamic exposure device and Sprague-Dawley (SD) rats were adopted. The exposure concentration of methyl mercaptan was 0.5 ± 0.1 ppm. The exposure procedure was 6 h/day, continuing for 30 days. The routine blood levels, oxidative stress levels in serum, immune molecule and cytokine in the serum and lung tissue were tested. Morphology injury of lung tissue was detected by Hematoxylin and Eosin (HE) staining. Apoptosis rate of alveolar epithelial cells were determined by TdT-mediated dUTP Nick End Labeling (TUNEL) assay. Reduction of body weight gain was observed in the male group during the exposure time, while there was no significant reduction of body weight gain in the female group. Pathological findings of terminal bronchiole constriction, alveolar congestion, and erythrocyte exudation confirmed the lung to be the main target organ. An apparent pneumonocyte apoptotic effection was also observed. Oxidative stress with lipid peroxidation, which affect blood antioxidant enzyme levels and induce apoptosis of alveolar epithelial cells, are recognized as a potential mechanism leading to terminal bronchiole constriction, alveoli congestion, and exudates of erythrocyte.Implications: The odor pollutants greatly affect the health of operation workers in the waste treatment plant, and odor complaints are becoming a major problem. The aim of this work is to identify the lung tissue inflammatory response of SD rats with chronic exposure to methyl mercaptan vapor at close to the recommended workplace concentration. In this study, we used a dynamic exposure device and chronic exposure model of rats to evaluate the potential toxicity effects of methyl mercaptan. The results showed that methyl mercaptan may cause lung inflammatory response and extensive lung cell apoptosis. Oxidative damage, with lipid peroxidation and alterations in blood antioxidant enzyme levels, was observed following methyl mercaptan exposure. This is recognized as a potential mechanism for terminal bronchiolar constriction, alveolar congestion, and erythrocyte exudation.

Removing of the Sulfur Compounds by Impregnated Polypropylene Fibers with Silver Nanoparticles-Cellulose Derivatives for Air Odor Correction

The unpleasant odor that appears in the industrial and adjacent waste processing areas is a permanent concern for the protection of the environment and, especially, for the quality of life. Among the many variants for removing substance traces, which give an unpleasant smell to the air, membrane-based methods or techniques are viable options. Their advantages consist of installation simplicity and scaling possibility, selectivity; moreover, the flows of odorous substances are direct, automation is complete by accessible operating parameters (pH, temperature, ionic strength), and the operation costs are low. The paper presents the process of obtaining membranes from cellulosic derivatives containing silver nanoparticles, using accessible raw materials (namely motion picture films from abandoned archives). The technique used for membrane preparation was the immersion precipitation for phase inversion of cellulosic polymer solutions in methylene chloride: methanol, 2:1 volume. The membranes obtained were morphologically and structurally characterized by scanning electron microscopy (SEM) and high resolution SEM (HR SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectrometry (FTIR), thermal analysis (TG, ATD). Then, the membrane performance process (extraction efficiency and species flux) was determined using hydrogen sulfide (H2S) and ethanethiol (C2H5SH) as target substances.

Tangerine, banana and pomegranate peels valorisation for sustainable environment: A review

Over the last decade the world has been generating a high quantity of tangerine peel waste (TPW), pomegranate peel waste (PPW) and banana peel waste (BPW). These peels have several economic benefits but there is mismanagement or inappropriate valorisation that could present risks to environment and public health. In the current review, we discussed the use of TPW, PPW and BPW directly for animal feed, soil fertilization, specific compost production and bio-adsorbent. We also discussed the valorisation of these peels for manufacturing the value-added products including enzymes, essential oil and other products that can be used in human food, in medical and cosmetic industry. Additionally, recent studies concerning the valorisation of these peels by biorefinery for bioethanol, biogas and biohydrogen production have been discussed. In the same context some other recent studies about valorisation of microorganisms isolated from these peels for medical, agronomic and industrial interests have been also discussed.

Ammonia and hydrogen sulphide odour emissions from different areas of a landfill in Hangzhou, China

This study examined the release characteristics of malodorous ammonia (NH₃) and hydrogen sulphide (H₂S) gases in different areas of a full-capacity operational landfill in Hangzhou, China. Gas samples were collected using static boxes from exposed working areas (EWAs), temporarily covered areas (TCAs), and final closure areas (FCAs), and were analysed using spectrophotometric methods. Gas release increased in the following order: TCA > EWA > FCA. The average concentrations of released NH₃ in these areas were 2763, 1171, and 27 mg m^-3, respectively, and those of H₂S were 2481, 631, and 10 mg m^-3, respectively. The concentrations of gases released from holes in the film in the temporarily covered and EWAs were significantly higher than the AEGL-3 level values specified by the Acute Exposure Guideline Levels (AEGL) Advisory Committee. EWAs were identified as key for odour control, where the highest NH₃ release was recorded at approximately 12:00. The diurnal variation in H₂S release was insignificant (p > 0.05). Therefore, the study shows that working in EWAs should be avoided at approximately noon. Adverse impacts on human health can be reduced by standardising procedures, using higher-quality films, and improving film installation procedures. The results of this study serve as a valuable reference for odour control in operational landfills.

Investigation and modeling of odors release from membrane holes on daily overlay in a landfill and its impact on landfill odor control

In the present work, we studied the NH₃ and H₂S odor fluxes between the exposed working area and the HDPE covering film holes of the daily overlay in an actual landfill site with a daily operating area of 1600 m² in Hangzhou, China. We showed that the odors were released from the membrane pores and the average concentrations of NH3 and H2S release reached 109.6 ± 56.6 and 86.0 ± 31.1 mg/m²/s, respectively. These concentrations are 43.8 and 57.3 times the exposed working surface. Furthermore, mathematical modeling based on the total amount of odor release revealed that there was a linear positive correlation between the total odor amount and the landfill operation area. However, the maximum number of film holes allowed on the covering layer has nothing to do with the working area and exposed working time, which is mainly determined by the HDPE film width in terms of ensuring the deodorizing effect of the covering operation. If the HDPE film with a width of more than 4 m is used, the number of film holes allowed within 100 m is more than 8. Therefore, in order to reduce the odor, the appropriate film width should be selected according to the actual operating conditions such as the mechanical operation level at the time of welding, the design of the landfill site, and the operational norms. This study explores the effect of film hole quantity of the daily cover in the landfill on the odor release from the landfill, which can provide an important reference for the design, operation, and decision-making of the daily cover operation of the sanitary landfill.

Trace gas emissions from municipal solid waste landfills: A review

Trace gas emissions from municipal solid waste (MSW) landfills have received increasing attention in recent years. This paper reviews literature published between 1983 and 2019, focusing on (i) the origin and fate of trace gas in MSW landfills, (ii) sampling and analytical techniques, (iii) quantitative emission measurement techniques, (iv) concentration and surface emission rates of common trace compounds at different landfill units and (v) the environmental and health concerns associated with trace gas emissions from MSW landfills. Trace gases can be produced from waste degradation, direct volatilisation of chemicals in waste products or from conversions/reactions between other compounds. Different chemical groups dominate the different waste decomposition stages. In general, organic sulphur compounds and oxygenated compounds are connected with fresh waste, while abundant hydrogen sulphide, aromatics and aliphatic hydrocarbons are usually found during the methane fermentation stage. Selection of different sampling, analytical and emission rate measurement techniques might generate different results when quantifying trace gas emission from landfills, and validation tests are needed to evaluate the reliability of current methods. The concentrations of trace gases and their surface emission rates vary largely from site to site, and fresh waste dumping areas and uncovered waste surfaces are the most important fugitive emission sources. The adverse effects of trace gas emission are not fully understood, and more emission data are required in future studies to assess quantitatively their environmental impacts as well as health risks.

The concentration of BTEX compounds and health risk assessment in municipal solid waste facilities and urban areas

In this study, human exposure to benzene, toluene, ethylbenzene, xylenes (BTEX), along with their respective risk assessment is studied in four major units (n = 14-point sources) of the largest municipal solid waste management facilities (MSWF) in Iran. The results were compared with four urban sites in Tehran, capital of Iran. Workers at the pre-processing unit are exposed to the highest total BTEX (151 μg m^-3). In specific, they were exposed to benzene concentrations of 11 μg m^-3. Moreover, the total BTEX (t-BTEX) concentrations measured over the conveyor belt was 198 μg m^-3 at most, followed by trommel (104), and active landfills (43). The mean concentration of ambient t-BTEX in Tehran is 100 μg m^-3. On average, xylenes and toluene have the highest concentrations in both on-site and urban environments, with mean values of 24 and 21, and 41 and 37 μg m^-3, respectively. Even though the non-carcinogenic risk of occupational exposure is negligible, BTEX is likely to increase the chance of carcinogenic risks (1.7E-05) for workers at the pre-processing unit. A definite carcinogenic risk of 1.3E-04, and non-carcinogenic effect, of HI = 1.6 were observed in one urban site. With the exception of the pre-processing unit, the citizens of Tehran had higher exposure to BTEX. Overall, BTEX concentrations in the largest MSWF of Iran remains an issue of public health concern.

Odour emission from primary settling tanks after air-tightening

The purpose of the present article was to determine odour emission rate from primary settling tanks after hermetisation. The paper presents the results of the research on odour emission from four settling tanks, covered with self-supporting aluminium domes with a diameter of 52 meters, located on urban wastewater treatment plants, with the planned flow capacity equal to 200 000 m3/day. Altogether, the olfactometry analysis of 189 samples of polluted air pulled from the domes with the use of an air blower which has efficiency of 12 000 m3/h was conducted. The results of odour concentration measurements were in a range of approximately 10 800 to 763 600 ouE/m3. Average odour emission rate was equal to 102 ouE/(s · m2). The obtained value is much higher than the literature data, available for non-hermetised settlers only. This rate enables better estimation of the odour stream that has to be deodorised after sealing the settling tanks.

Impact of Odor Nuisance on Preferred Place of Residence

Context of the research: Research is increasingly carried out to take into account the social behavior of residents, the type of industry located in the area, and perceived preference for the place of residence. The quality of life in urban space is increasingly seen as a problem of cooperation between various stakeholders. These studies not only identify factors and sources of odor emissions, but also serve as the basis for creating systems to alert people living in areas adjacent to industrial areas or harmful and unpleasant industrial emissions. In recent years, environmental issues, particularly unpleasant sensory experiences, have been one of the most important acceptance criteria. Aim of the article: The aim of the study is to assess the impact of odor nuisance in the south-eastern part of Kraków (Płaszów) on the residents’ decision to leave their place of residence. In particular, the research goal was achieved to indicate which of the unpleasant odors may cause a change of residence, as well as to assess the degree of their impact on the decision to move, taking into account the social and demographic characteristics of residents. New in the article: The novelty of the work was the finding out of the residents’ opinions about the quality of life by accepting the place of residence, taking into account the aspect of odor nuisance. Previous studies on odor nuisance have focused on the emission of odors from individual plants. A novelty of this research is its implementation in an urban area, in which numerous industrial plants are located, with various odors emitted. Research methodology: To assess odor nuisance, a measuring tool developed in accordance with VDI 3883 guidelines was used, based on the latest research results on odor and noise nuisance. The questionnaire was developed based on German experience. Conclusions from the research: The data obtained as a result of the research allow us to state that specific smells are so burdensome that they may cause the necessity to leave the place of residence, because the respondents feel various unpleasant smells that have an adverse impact upon the quality of life that they perceive. A possible need for relocation of domiciles out of the current place of residence due to unpleasant smells would affect the perceptible, specific level of grief—the greater it is, the more attached the residents are to their current place of residence.

Risk of respiratory hospital admission associated with modelled concentrations of Aspergillus fumigatus from composting facilities in England

Bioaerosols have been associated with adverse respiratory-related health effects and are emitted in elevated concentrations from composting facilities. We used modelled Aspergillus fumigatus concentrations, a good indicator for bioaerosol emissions, to assess associations with respiratory-related hospital admissions. Mean daily Aspergillus fumigatus concentrations were estimated for each composting site for first full year of permit issue from 2005 onwards to 2014 for Census Output Areas (COAs) within 4 km of 76 composting facilities in England, as previously described (Williams et al., 2019). We fitted a hierarchical generalized mixed model to examine the risk of hospital admission with a primary diagnosis of (i) any respiratory condition, (ii) respiratory infections, (iii) asthma, (iv) COPD, (v) diseases due to organic dust, and (vi) Cystic Fibrosis, in relation to quartiles of Aspergillus fumigatus concentrations. Models included a random intercept for each COA to account for over-dispersion, nested within composting facility, on which a random intercept was fitted to account for clustering of the data, with adjustments for age, sex, ethnicity, deprivation, tobacco sales (smoking proxy) and traffic load (as a proxy for traffic-related air pollution). We included 249,748 respiratory-related and 3163 Cystic Fibrosis hospital admissions in 9606 COAs with a population-weighted centroid within 4 km of the 76 included composting facilities. After adjustment for confounders, no statistically significant effect was observed for any respiratory-related (Relative Risk (RR) = 0.99; 95% Confidence Interval (CI) 0.96-1.01) or for Cystic Fibrosis (RR = 1.01; 95% CI 0.56-1.83) hospital admissions for COAs in the highest quartile of exposure. Similar results were observed across all respiratory disease sub-groups. This study does not provide evidence for increased risks of respiratory-related hospitalisations for those living near composting facilities. However, given the limitations in the dispersion modelling, risks cannot be completely ruled out. Hospital admissions represent severe respiratory episodes, so further study would be needed to investigate whether bioaerosols emitted from composting facilities have impacts on less severe episodes or respiratory symptoms.

Dispersion simulation of odorous compounds from waste collection vehicles: Mobile point source simulation with ModOdor

Odour pollution from municipal solid waste is a public nuisance and a threat to the health of residents nearby. Attention and understanding towards odour emissions from waste collection vehicles are insufficient, and dispersion simulation using conventional modelling tools cannot be applied because their special operational characteristics do not conform to either point or linear sources. This study proposes a new dispersion simulation method for mobile point sources with ModOdor, which is a 3D numerical model previously developed by the authors. The 12-month monitoring data show that ethanol, dimethyl disulphide and methylene chloride were identified as typical odorous compounds released from waste collection vehicles. Ethanol dispersion was simulated as a mobile point source for low- and high-speed modes by synchronously changing temporal and spatial grids in high precision. Results revealed the variations in concentration distribution, dispersion distance and impact duration. In general, a diameter of area with odour activity value higher than 0.1 was identified at approximately 30-50 m after stable dispersion. The impact duration varied from approximately 20 s to 40 s along with the tested source intensities, wind directions and speeds with a benchmark of 10 μg·m^-3. This study verified the applicability of the proposed method for the dispersion simulation of mobile point sources and provided useful approach and information for evaluating the odour pollution from waste collection vehicles.

Assessment of the environmental impact of sanitary and unsanitary parts of a municipal solid waste landfill

Only seven regional MSWLF in Serbia are considered sanitary, while about 3500 landfills operate without proper pollution control. This paper presents a unique opportunity to evaluate the impact of a closed landfill, and a new sanitary landfill, which are located next to each other. The following methodologies for the landfill impact assessment were applied, based on data from 2012 to 2017: Landfill water pollution index (LWPI) and Nemerow index (PI_GW) for groundwater, and the geo-accumulation (I_geo) and ecological risk (ERⁱ) indices and several PAH ratios for soil. The performance of the leachate control system was evaluated using two adapted pollution indices: LPI and the Nemerow index (PI_L). According to the obtained LWPI and PI_GW values, the quality of groundwater at the new landfill is improving (LWPI = 1.05-2.62; PI_GW = 0.52-1.29), while no significant changes were observed for the old landfill (LWPI = 3.06-5.13; PI_GW = 2.03-4.78). High concentrations of ammonia nitrogen (1.01-22.74 mg/l), Fe (0.76-57.11 mg/l), Ni (5.80-230.09 μg/l), Pb (4.2-202.4 μg/l) and ∑PAH₁₆ (150.93-189.55 ng/l) show the strong influence of the landfill on the groundwater quality at the old landfill, indicating the need for additional remediation action. High concentrations of Ni (21.9-133.0 mg/kg) and Cr (8.5-277.0 mg/kg) in the analyzed soil compared to other studies, as well as moderate I_geo values (I_geoNi = 0.36-1.88; I_geoCr = -1.20-1.52), raise concern and suggest the need for further monitoring. The high ERⁱ (158.6-295.0) and I_geo values (0.91-2.30) of Hg show significant potential ecological risk. LPI and PI_L values for early methanogenic phase leachate demonstrates the need to improve the leachate treatment system. The monitoring data and applied pollution indices indicate that Cr and As should be added to the EU Watch List of emerging substances, at least regarding EU potential candidate countries.

How Can Odors Be Measured? An Overview of Methods and Their Applications

In recent years, citizens’ attention towards air quality and pollution has increased significantly, and nowadays, odor pollution related to different industrial activities is recognized as a well-known environmental issue. For this reason, odors are subjected to control and regulation in many countries, and specific methods for odor measurement have been developed and standardized over the years. This paper, conceived within the H2020 D-NOSES project, summarizes odor measurement techniques, highlighting their applicability, advantages, and limits, with the aim of providing experienced as well as non-experienced users a useful tool that can be consulted in the management of specific odor problems for evaluating and identifying the most suitable approach. The paper also presents relevant examples of the application of the different methods discussed, thereby mainly referring to scientific articles published over the last 10 years.

Measurements techniques and models to assess odor annoyance: A review

Odors have received increasing attention among atmospheric pollutants. Indeed, odor emissions are a common source of complaints, affecting the quality of life of humans and animals. The odor is a property of a mixture of different volatile chemical species (sulfur, nitrogen, and volatile organic compounds) capable of stimulating the olfaction sense sufficiently to trigger a sensation of odor. The impact of odors on the surrounding areas depends on different factors, such as the amount of odors emitted from the site, the distance from the site, weather conditions, topography, other than odors sensitivity and tolerance of the neighborhood. Due to the complexity of the odor issue, the aim of this review was to give an overview of: (i) techniques (sensorial and analytical) that can be used to determine a quantitative and qualitative characterization; (ii) air dispersion models applied for the evaluation of the spatial and temporal distribution of atmospheric pollutants in terms of concentration in air and/or deposition in the studied domain; (iii) major sources of odor nuisance (waste and livestock); (iv) mitigation actions against odor impact. Among sensorial techniques dynamic olfactometry, field inspection, and recording from residents were considered; whereas, for analytical methodologies: gas chromatography-mass spectrometry, identification of specific compounds, and electronic nose. Both kinds of techniques evaluate the odor concentration. Instead, to account for the effective impact of odors on the population, air dispersion models are used. They can provide estimates of odor levels in both current and future emission scenarios. Moreover, they can be useful to estimate the efficiency of mitigation strategies. Most of the odor control strategies involve measures oriented to prevent, control dispersion, minimize the nuisance or remove the odorants from emissions, such as adequate process design, buffer zones, odor covers, and treatment technologies.

Assessment of the Effects of Wastewater Treatment Plant Modernization by Means of the Field Olfactometry Method

Methodological aspects of odor studies in ex-post analyses for Polish wastewater management facilities were analyzed based on the example of a modernized and enlarged wastewater treatment plant (WWTP) in Mazovia, in the vicinity of the Warsaw agglomeration. It is a mechanical–biological treatment plant with increased efficiency of biogen removal, using activated sludge in the treatment process, with a maximum hydraulic capacity of 60,000 m3/day. Olfactometric research was carried out by means of a method based on identification and characterization of the odor plume emitted from the examined source. This paper presents the results of odor intensity assessment (in sensory examinations according to a 6-stage scale) and odor concentration measurement (using portable field olfactometers) after the completion of the project, and compares them with similar studies conducted before the commencement of the investment. A total of 10 measurement series were carried out before modernization, and 12 after modernization of the WWTP. Odor concentration and intensity were determined, and the current meteorological situation was assessed at the measurement and observation points (receptors) located within the premises (in total 462 points) and around the WWTP (342 points). In each series of measurements on the windward side of the treatment plant, the background of air pollution with odorous substances was marked. The research showed that air flowing into the area of the sewage treatment plant is clean in terms of odor. During the research, basic sources of odor nuisance were identified, and their impact before and after modernization was characterized. The results presented in radar diagrams show changes in the percentage distribution of frequency of occurrence of individual intensity values at receptor points within and outside the area of the treatment plant. After modernization, a significant decrease in the concentration of odor emitted from the sludge dewatering building and sludge containers was determined. The air-tightness of the sewage channel (covered with concrete slabs and sealed) resulted in a significant decrease in the concentration of odor emitted from this source. Waste (in particular, sewage sludge) collected in the emergency waste storage yard was identified as the main source of odor nuisance. The waste, even after modernization, was an emitter of odorous compounds spreading outside the area of the WWTP. Nevertheless, as a result of the investment, the desired effect of reduction of the degree of odor nuisance was achieved.

On the interpretation of bioaerosol exposure measurements and impacts on health

Bioaerosols are recognized as one of the main transmission routes for infectious diseases and are responsible for other various types of health effects through inhalation and potential ingestion. Associating exposure with bioaerosol and health problems is challenging, and adequate exposure monitoring is a top priority for aerosol scientists. The multiple factors affecting bioaerosol content, the variability in the focus of each bioaerosol exposure study, and the variations in experimental design and the standardization of methods make bioaerosol exposure studies very difficult. Therefore, the health impacts of bioaerosol exposure are still poorly understood. This paper presents a brief description of a state-of-the-art development in bioaerosol exposure studies supported by studies on several related subjects. The main objective of this paper is to propose new considerations for bioaerosol exposure guidelines and the development of tools and study designs to better interpret bioaerosol data. The principal observations and findings are the discrepancy of the applicable methods in bioaerosol studies that makes result comparison impossible. Furthermore, the silo mentality helps in creating a bigger gap in the knowledge accumulated about bioaerosol exposure. Innovative and original ideas are presented for aerosol scientists and health scientists to consider and discuss. Although many examples cited herein are from occupational exposure, the discussion has relevance to any human environment. This work gives concrete suggestions for how to design a full bioaerosol study that includes all of the key elements necessary to help understand the real impacts of bioaerosol exposure in the short term. The creation of the proposed bioaerosol public database could give crucial information to control the public health. Implications: How can we move toward a bioaerosol exposure guidelines? The creation of the bioaerosol public database will help accumulate information for long-term association studies and help determine specific exposure biomarkers to bioaerosols. The implementation of such work will lead to a deeper understanding and more efficient utilization of bioaerosol studies to prevent public health hazards.

Do odour impact criteria of different jurisdictions ensure analogous separation distances for an equivalent level of protection?

Governments are increasingly introducing odour impact criteria (OIC) to determine separation distances between odour sources and residential areas. Previous studies have shown the wide range of OIC available for this purpose, depending on the desired level of protection against odour annoyance. However, it is unclear whether OIC with similar levels of protection can ensure analogous separation distances, which would reasonably be expected. This study presents a comparative analysis of separation distances calculated at two sites for different OIC, but all related to an equivalent level of protection. Here, the equivalent level of protection was defined for urban residential areas (land use), swine odour (hedonic tone) and new facilities (facility type). In this manner, the regulatory criteria currently enforced in Germany, Ireland, and Queensland (Australia) were selected as references for the investigation. The results clearly show that, even for an equivalent level of protection, disparate separation distances can be obtained. Differences in separation distances were found to be greater in prevailing wind directions compared to distances in additional wind directions. Overall, the results demonstrate a risk of poor conclusions in odour assessments. This means that care must be taken when adopting OIC for decision making, principally in those countries that have not yet established specific regulations to manage environmental odours. Concomitantly, the results stress the need for better harmonisation of the concept of the odour impact criterion and components thereof. By using perturbation analysis, it has also been found that the stack exit temperature influences the separation distances in a distinct way, reliant on the criteria used to determine the distances. This finding is of significance for input data collection in future odour modelling studies. Furthermore, approaches used to derive OIC, equivalence between dispersion modelling and field inspections (European standard EN 16841-1), as well as implications of the findings for regulatory practice are summarised and discussed.

Preliminary results of toxicity studies in rats following low-dose and short-term exposure to methyl mercaptan

The present study was carried out to evaluate the hematotoxicity and respiratory toxicity of methyl mercaptan in Sprague-Dawley rats. A dynamic exposure methodology was adopted in this study following 7 days of exposure by repeated inhalation. The concentration of methyl mercaptan used in the exposure was 0.5 ppm and the exposure time was 6 h/day for 7 days. After exposure, the rats were sacrificed to collect lung tissue and blood samples. Routine blood and serum biochemistry were conducted. Morphological injury of lung tissue was detected by hematoxylin and eosin staining. Decreased food consumption and body weight gain in both sexes were noted in the exposure group compared with the control group. Several significant changes in hematological parameters were observed. The results showed that the blood urea nitrogen (UREA) levels and superoxide dismutase (SOD) values were significantly decreased in exposed male rats. Malondialdehyde (MDA) in lung tissue was significantly increased in both males and females in the exposed group. In the histopathological examination of lung tissue, terminal bronchiole constriction, alveolar congestion, and erythrocyte exudation were observed, suggesting that the lungs may be target organs after inhaling methyl mercaptan and workers exposed to this concentration may cause some pulmonary stimulation and injury.

Emission characteristics of VOCs and potential ozone formation from a full-scale sewage sludge composting plant

Volatile organic compounds (VOCs) are the major components of the odor emitted from sewage sludge composting plants and are generally associated with odorous nuisances and health risks. However, few studies have considered the potential ozone generation caused by VOCs emitted from sewage sludge composting plants. This study investigated the VOC emissions from a full-scale composting plant. Five major treatment units of the composting plant were chosen as the monitoring locations, including the dewatered room, dewatered sludge, blender room, fermentation workshop, and product units. The fermentation workshop units displayed the highest concentration of VOC emissions at 2595.7 ± 1367.3 μg.m^-3, followed by the blender room, product, dewatered sludge, and dewatered room units, whose emissions ranged from 142.2 ± 86.8 μg.m^-3 to 2107.6 ± 1045.6 μg.m^-3. The detected VOC families included oxygenated compounds, alkanes, alkenes, sulfide compounds, halogenated compounds, and aromatic compounds. Oxygenated compounds, particularly acetone, were the most abundant compounds in all samples. Principal component analysis revealed that the dewatered room and dewatered sludge units clustered closely, as indicated by their similar component emissions. The product units differed from the other sampling units, as their typical compounds were methanethiol, styrene, carbon disulfide, and hexane, all of which were the products of the latter stages of composting. Among the treatment units, the fermentation workshop units had the highest propylene equivalent (propy-equiv) concentration. Dimethyl disulfide and limonene were the major contributors. Limonene had the highest propy-equiv concentration, which contributed to the increased atmospheric reactivity and ozone formation potential in the surrounding air. To control the secondary environmental pollution caused by the VOC emissions during sewage sludge composting, the emission of limonene and dimethyl disulfide must be controlled from the blender room and fermentation workshop units.

Effects of operating parameters on in situ NH3 emission control during kitchen waste composting and correlation analysis of the related microbial communities

Ammonia emission during composting results in anthropogenic odor nuisance and reduces the agronomic value of the compost due to the loss of nitrogen. Adjusting the operating parameters during composting is an emerging in situ odor control technique that is cheap and highly efficient. The effects of in situ NH₃ emission control were investigated in this study by simultaneously adjusting key operating parameters (such as C/N ratio, aeration rate, and moisture content) during the composting processes (C1-C9). Results showed that the average NH₃ emission concentrations for different treatments were in the order of C1 > C4 > C2 > C5 > C3 > C6 > C7 > C8 > C9. The total content of NH₃ emission (21.02 g/kg) in C9 (C/N ratio = 35, aeration rate = 15 L/min, and moisture content = 60%) was much lower than that (65.95 g/kg) in C1 (C/N ratio = 15, aeration rate = 5 L/min, and moisture content = 60%). The nitrogen loss ratio was 27.36% for C1, while 16.15% for C9. The microbial diversity and abundance in C9 and C1 were compared using high-throughput sequencing. The relationship between NH₃ emission, operating parameters, and the related functional microbial communities was also investigated. Results revealed that Nitrosospira, Nitrosomonas, Nitrobacter, Pseudomonas, Methanosaeta, Rhodobacter, Paracoccus, and Sphingobacterium were negatively related to NH₃ emission. According to the above results, the optimal values for different operating parameters for the in situ NH₃ control during kitchen waste composting were, respectively, moisture content of 70%, C/N ratio of 35, and aeration rate of 15 L/min, with the order of effectiveness from high to low being aeration rate > C/N > moisture. This information could be used as a valuable reference for the in situ NH₃ emission control during kitchen waste composting.

Socio-environmental assessment of a landfill using a mixed study design: A case study from México

Municipal solid waste management is a challenge for local authorities since mismanagement leads to environmental damage and social discontent. The objective of this study was to assess in an integrated manner the socio-environmental situation of a municipal landfill from México, using a design of mixed methods, which considered a quantitative evaluation of physicochemical and microbiological variables measured in leachates, surface and groundwater samples, soil and air, and a qualitative evaluation by in-depth interviews with the near-by inhabitants about their perception of the impacts of the landfill. The results show that leachates polluted the soil and surface water in a radius of up to 500 m from the landfill, but did not reach the groundwater, while the mean concentrations of PM₁₀, Mn, and Ni measured in air samples at the landfill of 146 µg m^-3, 0.12 µg m^-3, 0.10 µg m^-3, respectively, in the dry season and of Mn and Ni of 0.13 µg m^-3 and 0.11 µg m^-3, respectively, in the rainy season, surpassed permissible limits. From the residents perspective the landfill pollutes soil, water and air and it contributes to vehicle traffic and noise, promotes harmful fauna and disturbs the esthetic view. Air measurements coincide with social perception and in general, the applied mixed study design helped to assess in an integrated manner the socio-environmental concerns and to give advice to improve the current management of the landfill.

Estimating Aspergillus fumigatus exposure from outdoor composting activities in England between 2005 and 14

Bioaerosols, ubiquitous in ambient air, are released in elevated concentrations from composting facilities with open-air processing areas. However, spatial and temporal variability of bioaerosols, particularly in relation to meteorology, is not well understood. Here we model relative concentrations of Aspergillus fumigatus at each postcode-weighted centroid within 4 km of 217 composting facilities in England between 2005 and 2014. Facilities were geocoded with the aid of satellite imagery. Data from existing bioaerosol modelling literature were used to build emission profiles in ADMS. Variation in input parameters between each modelled facility was reduced to a minimum. Meteorological data for each composting facility was derived from the nearest SCAIL-Agriculture validated meteorological station. According to our results, modelled exposure risk was driven primarily by wind speed, direction and time-varying emissions factors incorporating seasonal fluctuations in compostable waste. Modelled A.fumigatus concentrations decreased rapidly from the facility boundary and plateaued beyond 1.5-2.0 km. Where multiple composting facilities were within 4 km of each other, complex exposure risk patterns were evident. More long-term bioaerosol monitoring near facilities is needed to help improve exposure estimation and therefore assessment of any health risks to local populations.

Full-scale composting of sewage sludge and market waste: Stability monitoring and odor dispersion modeling

The aim of this study was to assess the odor immission derived from full-scale composting of different abundant and highly pollutant organic waste: sewage sludge with bulking agent (SL), sewage sludge pretreated through anaerobic digestion and supplemented with bulking agent (SL-AD), and market waste with olive leaves (MW-OL). The combination of dynamic olfactometry and Gaussian dispersion modeling allowed both the quantification of odor emissions from each waste and the evaluation of their global odorous impact in nearby urban areas. Wind speed, summer and winter seasons, and atmospheric conditions were considered in the dispersion model. The results revealed that high wind speed (2.6 m/s) increases the global odor immission in summer season, independently of atmospheric stability. However, the maximum odor immission concentration recommended for composting process was not exceeded in any case, which depends on each country/region. The experimental results also enable to evaluate the influence of several physico-chemical variables on odor emissions derived from composting. The removal of nitrogen and volatile solids was the main cause for odor generation. Moreover, the microbiological activity of each substrate was monitored throughout the process and different percentages of biodegradability were quantified depending on the type of substrate and pretreatment applied.