Assessing the Impact of a Municipal Pesticide Use Bylaw: A Quasi-Experimental Evaluation

Abstract

ISEE-631 Objective: To assess initial impacts of a municipal bylaw restricting the nonessential use of chemical pesticides outdoors. Materials and Methods: We devised a “pre-during” quasiexperimental design using data from the Rapid Risk Factor Surveillance System, an ongoing monthly telephone survey of approximately 100 adult residents, administered in English by an independent research organization on behalf of participating Public Health units in Ontario, Canada. Health units may choose to collect information on lawn care practices using standardized questions. In the intervention jurisdiction (“I”), data was collected immediately before and following the first phase of bylaw implementation, which included education campaigns and education-based enforcement. The comparison jurisdiction (“C”) was the only other jurisdiction that collected the same data over the same time period; it had no pesticide bylaws during the data collection period. Survey information about the summer of 2003 constitutes the “pre” data (nI1 = 608; nC1 = 690), and information about the summer of 2005 is the “during” data (nI2 = 1043; nC2 = 811). Results: In the intervention jurisdiction the overall proportion of households reporting any pesticide use on their lawns decreased by 35%, from 37% ± 5% of households with lawns in 2003 to 24% ± 7% in 2005. Fewer householders themselves applied pesticides on their lawns (down from 25% ± 5% to 18% ± 3% across years), and lawn care companies used pesticides at substantially fewer households (from 60% ± 11% of the households served in 2003 to 36% ± 7% in 2005). In the comparison jurisdiction, the overall number of households reporting any pesticide use on their lawns decreased by only 9%. Conclusions: Preliminary data suggest that the bylaw has effectively decreased the proportion of households using pesticides to care for their lawns. More conclusive evidence will require a longer period of comparable data collection in these jurisdictions and in other jurisdictions with and without pesticide bylaws.