施工隧道粉尘质量浓度转换系数K值变化规律

对施工隧道粉尘采用滤膜粉尘采样器与光散射数字粉尘计同步测定，通过计算求得转换系数Ｋ值。结果表明，采样位置距发尘源距离和作业环境粉尘浓度对Ｋ值有较大影响，粉尘浓度与Ｋ值间呈线性相关。这种影响是由于粉尘颗粒中位径变化而引起的。发尘源非连续发尘时不但引起粉尘浓度变化，而且引起中位径改变。由此提示，由Ｋ值乘相对质量浓度换算质量浓度是不适合的。

Study on variational regularity of airborne dust concentration conversion factor(K-Factor) in tunnel under construct

The conversion factor(K-Factor) was obtained by parallel measurement of air borne dust of workingt environment with a light scattering dust meter and gravimetry with filtered membrane.The results showed that the distance from sampling site to the generated origin of dust and the concentration of airborne dus in working field affected K-Factor obviously.The K-Factor correlated linearly with dust concentration,this is due to the variation of dust particle median diameter.When the dust in working field given out intermittently,not only the dust concentration,but also the particle median diameter has been changed.Therefore,the results show that it will be unsuitable to calculate dust concentration by K-Factor multipling relative concentration.