Aprimoramento de estratégias regulatórias para gestão de odor ambiental: Improvement of regulatory strategies for environmental odour management

Environmental odour-related air pollution can cause adverse effects on human health in acute and chronic exposures. Conflicts between communities and odour sources are usually mediated by environmental agencies through regulations. However, disparities are found in the frameworks used to manage emissions and impacts of odour. This lack of harmonization and standardization creates gaps that urgently need to be narrowed. Accordingly, the objective of this Thesis is to contribute with the improvement of regulatory strategies for environmental odour management. To this end, two works were conducted: (i) odour regulations in 28 countries around the world were organized and revised, and (ii) the inter-annual variability of direction-dependent separation distances was evaluated. The comprehensive collection of regulatory instruments identified and categorized the approaches used to legislate on odour: maximum impact standard, separation distance standard, maximum emission standard, maximum annoyance standard, technology standard. The association of a time series of odour concentration in ambient air, calculated by dispersion models, with the so-called odour impact criteria (OIC) was identified as one of the tools most used to evaluate odour impacts. The different components of the OIC (i.e. odour concentration threshold, percentile and averaging time) were synthesized, compared and discussed. The review study contemplated why odour legislation is challenging to establish, how evidence was collected to determine odour thresholds in ambient air, consideration of separation distances, best available technologies, and application of OIC. Moreover, it has been demonstrated that differences in the measured odour concentration may occur across all odour units, although these units are considered theoretically equivalent. Mutual elements of successful legislations were captured, and an integrated multi-tool strategy was recommended to manage on environmental odour. The methods and tools that comprise the integrated strategy are encompassed into predictive, observational/empirical and mitigation/control. This strategy has the potential to be a worldwide-key contribution of significant importance in the search for greater harmonization among odour laws through a solid common basis. The evaluation of inter-annual variability of directiondependent separation distances investigated whether a single meteorological year is sufficient to obtain representative odour impact patterns. The AERMOD dispersion model was applied to calculate separation distances to avoid odour conflicts at two sites. The calculations were conducted for São José dos Pinhais (Brazil, near Curitiba) and GroßEnzersdorf (Austria, near Vienna) using 5 years of hourly meteorological observations for each site. It was confirmed that longer time series of meteorological data provide an understanding of the "average" and longterm conditions of how the separation distances are shaped around the odour sources. However, these data are not always available, and processing longer meteorological time series requires more time. A low degree of year-to-year variation of the separation distances was determined (mean coefficient of variation from 8% to 21%). Thus, a single year of meteorological data is an adequate compromise to achieve reliable accuracy. This finding can improve the relationship between time/financial resources and accuracy in odour dispersion modeling studies. Finally, this Thesis has the potential to effectively improve odour legislations currently in force, in addition to promoting the development of new regulations in countries with no instruments to deal with environmental odour.