Hugo Morales WhenWhai Li Helmut Paschold David Trujillo

1
The University of Texas at El Paso Department of
Civil Engineering
The Effects of Evaporative Cooling on
Indoor/Outdoor Air Quality in the El Paso
Border Region
Hugo Morales When-Whai Li Helmut Paschold David
Trujillo
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Acknowledgements

• Texas Higher Education Coordination Board.
• Center of Environmental Resource Management
• EPA Environmental Student Support Program
• MIE-REU
• UTEP Civil Engineering/Air Quality Research Group
  Leonardo Ledesma, Karla Guajardo, Julian
  Chianelli, Ruben Orquiz, Joel Mora, Humberto
  Garcia.

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Publications Presentations

• Atmospheric Environment Journal
  (www.elsevier.com)
• Laboratory study of the impact of evaporative
  coolers on indoor PM concentrations.
• Elemental analysis of airborne particulate mater
  and cooling water in Texas residences.
• Correlations Between Short-term Indoor and
  Outdoor PM Concentrations at Residences with
  Evaporative Coolers.
• Rio Grande/Rio Bravo Environmental Conference.
  South Padre Island, TX
• T-Tech Health Sciences Seminar
  El Paso, TX
• MIE Poster Presentation

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Objective

• Evaluate the effect of evaporative cooling on
  indoor PM levels
• Conduct a laboratory experiment
• Conduct field tests in homes
• Analyze samples
• Analyze results

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Introduction

• Evaporative Cooler
• Found in 90 of El Paso homes
• Extensively used in Southwest U.S. India,
  Australia and South Africa. There are about 4.5
  million units in the U.S.

An economic means of cooling based on water
evaporation

• Two types of Pads
• Aspen Pad
• Rigid Media

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Instrumentation

• TEOM
• US EPA PM10 Federal Equivalent Method
• Mass is measured by change in frequency
• Modified with auxiliary flowline filter
  cartridges

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Laboratory Experiment
Simulate under a controlled environment the
impact of evaporative coolers.
Test Chamber
Tested all possible conditions. (low, high, vent,
wet, b/o, tap, DI, PM2.5 10)
Indoor/Outdoor Ratios and correlations determined
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Laboratory Experiment
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Laboratory Experiment
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Laboratory Experiment
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Laboratory Experiment Conclusions

• Evaporative cooling has a greater effect on PM10
  compared to PM2.5
• During dry (vent) operation, PM10 removal is 30
  greater than for PM2.5
• Wet operation removes much more PM than dry
• Impaction was the greatest factor for aspen pad
  PM removal, 5.0 mm and larger PM, and for much or
  the rigid media reduction.

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Field Sampling
Samples were obtained from 10 houses
Outdoor TEOM Indoor TEOM Two Days for each
parameter, PM2.5 10 Indoor activity
questionnaire
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Field Sampling
PM10 Diurnal Pattern Wind
PM2.5 Diurnal Pattern Wind
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Field Sampling
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Field Sampling Conclusions

• Evaporative cooling is slightly more effective in
  reducing PM10 I/O ratios, with higher R2
  correlations, than for PM2.5
• No correlation can be assumed for PM2.5 data with
  the coolers turned off
• Indoor human activities have a significant impact
  on indoor PM, especially for PM2.5
• Evaporative cooling appears to shorten the
  duration of PM concentration spikes associated
  with human activity

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Elemental Analysis

• Air samples collected by modification of TEOM,
  utilizing the auxiliary flow line for both PM
  sizes, approximately 48-hours each
• Water samples obtained from tap and cooler pan
  sources at each house

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Elemental Analysis PM10
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Elemental Analysis PM2.5
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Elemental Analysis Conclusions

• PM I/O ratios, especially PM10, show fairly high
  R2
• I/O consistency is achieved by high ventilation
  rates
• Cooler pan water elements are not introduced into
  indoor PM

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Final Conclusions

• Evaporative cooling reduces outdoor to indoor PM,
  with a greater effect on PM10 than PM 2.5
• Indoor human activities have a significant impact
  on indoor PM concentrations, especially for
  PM2.5, but these effects are reduced by
  evaporative cooling
• The evaporative cooler water does not contribute
  elements to indoor PM

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Thank You