Fig. 1From: Improving the performance of spray operators through monitoring and evaluation of insecticide concentrations of pirimiphos-methyl during indoor residual spraying for malaria control on Bioko IslandDistribution of IRS pesticide concentrations from household surfaces. Histogram of residual concentration of pesticide sampled from 119 households after organized malaria elimination efforts. Concentrations sampled from surfaces (n = 714) were determined by HPLC and presented with reference lines for samples below 0.5 g/m2 (sup-optimal dose) and above 1.5 g/m2 (no additional benefit)Back to article page