Offensive odorants released from stormwater catch basins (SCB) in an urban area.

The potent role of stormwater catch basins (SCB) as a source of malodor in urban areas has been recognized because of its active involvement in the production and release of diverse odorants. Here, the status of odor pollution was investigated from two types of SCBs (i.e., wet and dry systems) by measuring a list of offensive odorants (i.e., reduced sulfur compounds (RSC), carbonyl compounds, nitrogenous, volatile organic compounds (VOCs), and fatty acids). Samples from those SCB systems were collected three times a day for five non-consecutive days. According to our study, H(2)S recorded consistently the highest mean values of 2554 ppb (wet) and 699 ppb (dry system) among all major offensive odorants. In contrast, the most prevalent VOCs were distinguished between methyl ethyl ketone (250 ppb in dry SCB) and toluene (32.8 ppb in wet SCB). In general, most odorants tend to exhibit relative enhancement in the afternoon, regardless of SCB types. If the concentration values of each odorant are converted into odor intensity (OI), the RSC group was identified as the key components of odor formation in SCB. If the OI values of each individual component are bound to yield sum of odor intensity (SOI), their values for wet and dry system were 4.99 and 4.25, respectively. In light of the fact that SCBs can serve as a potential odor source in urban areas, it should be managed and maintained properly to suppress the propagation of odor into the surrounding environments.