Determining distribution by wind

Table A presents the assumptions used for the calculations in the wind distribution model (see Figure, p.13).

**TABLE A**

Parameter | Assumptions |

Emissions from the store | Diffuse, through natural ventilation only |

Average wind velocity | 4 m/year |

Concentration of pesticides in store | 1 000 mg/m^{3} |

Emission rates | 25; 12.5; 2.5 kg/h for open, moderately open and closed stores, respectively |

Distribution model | Gaussic plume model (short term deposition) |

Atmosphere stability | Neutral |

Diameter pesticides particles | Moderately fine (80%d<4um; 17%4<d<10 um; 3% d>10 um) |

Emission frequency | Every day throughout the year |

The model does have its limitations. The fact that the calculations are carried out for the worst-case parameters means that the maximum emission and maximum distance are calculated to the effect that the long-distance calculations will be overestimates, and the short-distance calculations will be underestimates.