Diesel engine exhaust (DEE) and crystalline silica exposures occur simultaneously in the mining industry, and occupational sampling campaigns can be time- and cost-consuming. The authors evaluated a dual-port system for simultaneous sampling of DEE and crystalline silica in laboratory and field conditions. Laboratory tests evaluated the operation of pumps during 8 h sampling and the intensity of the flow variation for various filter loading conditions and for different modes of operation. Field validation was performed in an underground mine. Pumps operated in constant flow or constant pressure modes. Tests in constant flow mode showed that when the flowrate increased on one side of the system, it decreased on the opposite side according to the loading intensity. Tests in constant pressure mode showed that flowrates systematically decreased when using loaded cassettes. However, the higher the backpressure setting, the lower the flow variation was. Flow variations during field tests were generally within the acceptable ±5% range. However, significant flow variations were identified in higher concentrations. A significant negative correlation was found between flowrate variation and total carbon concentration. While the majority of tests support the use of the dual-port for evaluating concomitant exposures, results highlight the possibility of filter overloading as a cause of flowrate changes.

在采矿业中，柴油机废气（DEE）和结晶二氧化硅的暴露同时发生，因此职业采样活动可能既费时又费钱。作者评估了在实验室和现场条件下同时采样DEE和结晶二氧化硅的双端口系统。实验室测试评估了8小时采样期间泵的运行情况以及各种过滤器负载条件和不同运行模式下流量变化的强度。现场验证是在地下矿井中进行的。泵以恒定流量或恒定压力模式运行。在恒定流量模式下的测试显示，当系统一侧的流量增加时，根据负载强度，另一侧的流量减少。恒压模式下的测试表明，使用带负载的暗盒时，流量会系统地降低。但是，背压设置越高，流量变化越小。现场测试期间的流量变化通常在可接受的±5％范围内。但是，在较高的浓度下，发现了明显的流量变化。发现流量变化与总碳浓度之间存在显着的负相关。尽管大多数测试都支持使用双端口来评估伴随的暴露，但结果突出显示了由于流量变化而导致过滤器过载的可能性。在较高的浓度下，流量明显变化。发现流量变化与总碳浓度之间存在显着的负相关。尽管大多数测试都支持使用双端口来评估伴随的暴露，但结果突出显示了由于流量变化而导致过滤器过载的可能性。在较高的浓度下，流量明显变化。发现流量变化与总碳浓度之间存在显着的负相关。尽管大多数测试都支持使用双端口来评估伴随的暴露，但结果突出显示了由于流量变化而导致过滤器过载的可能性。