A Simple and Practical Methodology for Monitoring the Peak Concentration of Odorous Gases in Air

Odour nuisance impacting residents' life comfort is the result of the presence in air of numerous species, mainly gaseous, negatively interacting with the human olfactory system. It is well known that odour nuisance does not depend on the mean gas concentrations over long averaging times (of the order of one hour), but on their turbulent fluctuations, that can be some orders of magnitude greater than hourly averaged values. Currently, the direct measure of intensity and frequency concentration peaks can be carried out only for a few species and requires high-cost instruments, representing a serious challenge for Environmental Protection Agencies responsible for public health and environmental protection. This paper describes the intermediatecost methodology developed by ARPA Lazio, the environmental agency responsible for the Italianadministrative region which includes Rome, to monitor and assess the presence of odorous gases. It is based on mobile vehicles equipped with intermediate-cost analyzers for some of the main odorous gases, successfully deployed in more than fifteen field campaigns carried out all over the region in the last five years. As an example, results from one of the campaigns are also reported briefly. Such an effort is mainly motivated by the need to fulfil institutional duties, but it also supports the possibility of building a network of affordable instruments capable of routinely monitor odour nuisance impact over relatively large regions.