Determination of Dose–Response Relationship to Derive Odor Impact Criteria for a Wastewater Treatment Plant

Municipal wastewater treatment plants (WWTPs) inside cities have been the major complained sources of odor pollution in China, whereas there is little knowledge about the dose–response relationship to describe the resident complaints caused by odor exposure. This study explored a dose–response relationship between the modelled exposure and the annoyance surveyed by questionnaires. Firstly, the time series of odor concentrations were preliminarily simulated by a dispersion model. Secondly, the perception-related odor exposures were further calculated by combining with the peak to mean factors (constant value 4 (Germany) and 2.3 (Italy)), different time periods of “a whole year”, “summer”, and “nighttime of summer”, and two approaches of odor impact criterion (OIC) (“odor-hour” and “odor concentration”). Thirdly, binomial logistic regression models were used to compare kinds of perception-related odor exposures and odor annoyance by odds ratio, goodness of fit and predictive ability. All perception-related odor exposures were positively associated with odor annoyance. The best goodness of fit was found when using “nighttime of summer” in predicting odor-annoyance responses, which highlights the importance of the time of the day and the time of the year weighting. The best predictive performance for odor perception was determined when the OIC was 4 ou/m3 at the 99th percentile for the odor exposure over time periods of nighttime of summer. The study of dose–response relationship could be useful for the odor management and control of WWTP to maximize the satisfaction of air quality for the residents inside city.

Odor Annoyance Assessment by Using Logistic Regression on an Example of the Municipal Sector

Around the sewage treatment plant, in the area affected by a large number of complaints about odor annoyance, field measurements of odor properties and questionnaires were carried out. It was confirmed that the inhabitants of the zone closest to the plant are most exposed to the smell, the most intense smell comes from the sludge dryer building, and smells from primary settling tanks and sediment plots are perceived as unpleasant. The analysis of surveys confirmed the problem of odor nuisance, especially in the immediate vicinity, where over 50% of respondents considered odor annoyance as extreme. A division of respondents was introduced into those experiencing severe nuisance and those for whom the smell was not annoying. Then, to relate the probability of occurrence of odor nuisance with a group of independent variables, logistic regression was used to describe the impact of independent variables on the dichotomous dependent variable. It has been shown that the likelihood of experiencing odor nuisance increases with the increase in the intensity of current odors, the parallel noise, and in people who focus on the existing smell, and decreases with increasing satisfaction with their health and in the case of regularly occurring odor.

Comparison of Hydrogen Sulfide Concentrations and Odor Annoyance Frequency Predictions Downwind from Livestock Facilities

Estimating and measuring the occurrence of a sensation, odor, around livestock facilities is challenging. This research compares the estimated frequency of odor nuisance with measured hydrogen sulfide (H2S) concentrations at various distances around a swine and a dairy operation, and discusses the results based on time of day, weather conditions, distance, and topography. The estimated odor annoyance-free and odor annoyance frequencies were based on a publically available calculator of odor impact derived from average odor emission rates, historical, and regional weather patterns, and dispersion modeling. Continuous monitoring of H2S was by single point monitors (SPM) at locations around the operations. Time-weighted average H2S concentrations were less than 10 ppb for odor annoyance-free frequencies, and less than 10 to at least 73 ppb for odor-annoyance frequencies. Verifying a proxy odor indicator can help update odor annoyance models and respond to site-specific concerns for existing facilities.

Concentration Fluctuations and Odor Dispersion in Lagrangian Models

In this paper, a review of the Lagrangian stochastic models developed in the last decades for the simulation of the concentration–fluctuation dispersion is presented. The main approaches available in the literature are described and their ability in reproducing the higher order moments of the probability density function is discussed. Then, the Lagrangian approaches for evaluating of the odor annoyance are presented. It is worth to notice that, while Lagrangian stochastic models for mean concentrations are well-known and their ability in correctly reproducing the observation is well assessed, concerning concentration fluctuations the approaches are often new and unknown for most of the scientific community.

Evaluating Urban Odor with Field Olfactometry in Camden, NJ

Odor annoyance negatively impacts residents of communities adjacent to persistent nuisance industries. These residents, often with a high percentage of minority or otherwise marginalized residents, experience subjective and objective impacts on health and well-being; yet, reliable methods for quantifying and categorizing odors have been elusive. Field olfactometry is integral to the study of odor annoyance experienced by communities as it includes both qualitative (human perception) and quantitative (intensity measurement) dimensions of human odor experience and has been employed by municipalities in the U.S. to evaluate odor pollution levels. Cartographic visualization of odor data recorded using a field olfactometer offers further opportunity to evaluate potential patterns of odor annoyance, yet the use of field olfactometry and geographic information systems have not been frequently employed by geographers. By employing a mixed-methods approach to evaluate odor pollution, this study addresses the environmental justice context by quantifying and categorizing the presence of odor pollution in Waterfront South, a neighborhood in Camden, NJ previously identified for its disproportionate malodor burden. This study offers support to mixed methods research and the need for monitoring subjective and objective impacts in communities with compounding odor nuisance industries.

An Innovative Methodological Approach for Monitoring and Chemical Characterization of Odors around Industrial Sites

This study aims to highlight the potentialities of an innovative methodological approach for monitoring and chemical characterization of odors, especially in high concern and complex industrial areas. The proposed approach was developed in order to monitor and identify odor-active compounds responsible for odor annoyance coming from different industrial activities such as landfills, wastewater treatment plants, and petroleum plants. The methodology’s strengths are as follows: (1) the tailored approach for each typology of industrial areas/sites; (2) integration of technologies able to provide real-time information about the emissive sources; (3) mapping of air pollutants on the territory aimed to identify and discriminate among different fugitive emissions responsible for odor annoyance; (4) collection of more representative air samples only during the nuisance events, thanks to the implementation of innovative sampling systems and citizens’ involvement; and (5) increased analytical sensitivity in odor-active VOCs detection. This methodology reveals to be a useful tool to collect real-time information about the emission sources and their impacts on the surrounding area giving credit to citizens’ complaints. Moreover, it allows to overcome the limitations of the conventional approaches related to the lack of instrumental sensitivity and to identify the chemical compounds contributing to the odor annoyance.

Self-Ratings of Olfactory Performance and Odor Annoyance Are Associated With the Affective Impact of Odor, but Not With Smell Test Results

Our aim was to explore factors potentially associated with subjective (self-rated) and objective (measured using the Sniffin’ Sticks Extended test) olfactory performance in the general population without olfactory disorders. We studied associations between olfactory performance and how important odors were in determining liking for new places, things, and people (measured using the Affective Impact of Odor scale) and the average annoyance caused by odors in 117 adults (83 women, 34 men; age 18–69 years, mean age 32 years). In a subset of 44 participants, we also studied associations between olfactory performance and spice odor identification task scores (14 odors) and the number of herbs and spices consumed. Self-rated olfactory acuity and odor-related annoyance were associated with the Affective Impact of Odor scores, but neither correlated with the smell test results. Instead, the number of spices consumed correlated with spice odor identification score ( r = .50) and the identification (but not threshold nor discrimination) subscore of the Sniffin’ Sticks test ( r = .49). Our results suggest that a tendency to perceive odors in affective terms may be associated with overestimation of olfactory abilities and that recurrent exposure to a large variety of spice odors may improve performance on odor identification.