7
CONCLUSIONS
In this study, the DCAC was shown to reduce diesel par-
ticulate matter (DPM) concentrations by over 80% when
measured 15 inches under the center of the DCAC.
Although previous work documented the ability of blowing
DPM-free air over a miner to reduce DPM concentrations,
this study was the first to test the DCAC’s reduction ability
when using a filter to remove DPM prior to blowing over
the miner. The filter used in this test was a MERV 16 and
filtered the high concentrations of DPM for 394 minutes
with only a 4.8% reduction in air volume moving through
the system. These results show the promise of this equip-
ment for reducing the exposure of underground blasters to
DPM while working in areas of elevated DPM concentra-
tions and low ventilation conditions. The low ventilation
scenarios used in this study are typical for underground
blasters that regularly work in areas with ventilation below
100 fpm. Although this work shows significant reductions
using the DCAC, actual reductions for underground blast-
ers will depend on the amount of time blasters remain
under the DCAC while working. Additional field work in
operating mines is necessary to confirm the results of this
study and to determine expected reductions considering
real-life work habits of underground blasters.
LIMITATIONS
The amount of data collected for mapping the reductions
for other locations besides the center is limited, and addi-
tional data would be beneficial. This study did not deter-
mine how work habits, such as leaning away from the
DCAC, may affect the overall DPM exposures. This study
also did not determine the effects of ventilation on the
DCAC. Other studies have demonstrated that ventilation
can affect the efficiency of the DCAC. However, for the
miners who would most likely use this DCAC, the ventila-
tion is usually not high in their work zones.
ACKNOWLEDGEMENT
The authors would like to acknowledge the work of the
late Dr. James Noll, who initiated this research effort, and
many others before his untimely passing. In addition, we
would like to acknowledge the help of Dr. John Heberger
for accessing the MSHA database for DPM exposure data.
DISCLAIMER
The findings and conclusions in this report are those of
the authors and do not necessarily represent the official
position of the National Institute for Occupational Safety
and Health, Centers for Disease Control and Prevention.
Mention of any company or product does not constitute
endorsement by NIOSH.
Figure 9. Heatmap showing average particle number reduction over the three tests
using the APS across the operating DCAC
CONCLUSIONS
In this study, the DCAC was shown to reduce diesel par-
ticulate matter (DPM) concentrations by over 80% when
measured 15 inches under the center of the DCAC.
Although previous work documented the ability of blowing
DPM-free air over a miner to reduce DPM concentrations,
this study was the first to test the DCAC’s reduction ability
when using a filter to remove DPM prior to blowing over
the miner. The filter used in this test was a MERV 16 and
filtered the high concentrations of DPM for 394 minutes
with only a 4.8% reduction in air volume moving through
the system. These results show the promise of this equip-
ment for reducing the exposure of underground blasters to
DPM while working in areas of elevated DPM concentra-
tions and low ventilation conditions. The low ventilation
scenarios used in this study are typical for underground
blasters that regularly work in areas with ventilation below
100 fpm. Although this work shows significant reductions
using the DCAC, actual reductions for underground blast-
ers will depend on the amount of time blasters remain
under the DCAC while working. Additional field work in
operating mines is necessary to confirm the results of this
study and to determine expected reductions considering
real-life work habits of underground blasters.
LIMITATIONS
The amount of data collected for mapping the reductions
for other locations besides the center is limited, and addi-
tional data would be beneficial. This study did not deter-
mine how work habits, such as leaning away from the
DCAC, may affect the overall DPM exposures. This study
also did not determine the effects of ventilation on the
DCAC. Other studies have demonstrated that ventilation
can affect the efficiency of the DCAC. However, for the
miners who would most likely use this DCAC, the ventila-
tion is usually not high in their work zones.
ACKNOWLEDGEMENT
The authors would like to acknowledge the work of the
late Dr. James Noll, who initiated this research effort, and
many others before his untimely passing. In addition, we
would like to acknowledge the help of Dr. John Heberger
for accessing the MSHA database for DPM exposure data.
DISCLAIMER
The findings and conclusions in this report are those of
the authors and do not necessarily represent the official
position of the National Institute for Occupational Safety
and Health, Centers for Disease Control and Prevention.
Mention of any company or product does not constitute
endorsement by NIOSH.
Figure 9. Heatmap showing average particle number reduction over the three tests
using the APS across the operating DCAC