Exposure to spores during mowing: a comparative assessment of workers, parks and town

Abstract

To find out if cutting grass in urban parks can lead to increased exposure to aeroallergens through aerosolization of grass particles and their contaminants, volumetric samples were taken from different sites on a logarithmic scale from the source. Samples were taken on the worker at breathing level (personal exposure), in the park a few hundred metres from the worker (local exposure) and at the University of Montréal campus, a few kilometres from the source (regional exposure). Samples were taken in July 1991 and July 1992. Two types of sampling (on filters and on slides) and two types of spore extraction (through destruction of the filters or through recuperation with gelatine) were compared. The results show that there is a large increase in exposure at the personal level (1000–2000%) and a significant increase at the local level (100–400%) as compared to regional exposure. Slides collected on average 13 times more spores than filters. The recuperation method allowed for the recovery of a higher diversity of spores. However, the destructive method made it possible to identify a comparable level of exposure to the one found on slides. Although the ubiquitousCladosporium dominated in almost all samples, local and personal samples were often dominated by plant pathogenic fungi of the Rusts and Smuts types. This opens a new area of investigation in aeroallergen research, since these spores have seldom been identified or considered in exposure assessment, and their allergenicity is still unknown. In addition, there is still uncertainty in the methodologies for sampling to determine worker exposure.