Document Type

Restricted Campus Only

Publication Date

Spring 2001

Abstract

The purpose of the ambient air pollution project is to implement a real-time dynamic and modular ozone monitoring system on the roof of the Marrs Mclean Science Building (MMS) at Trinity University. The ozone monitoring system consists of an ultraviolet radiation sensor, an ozone monitor, a nitrogen oxide analyzer, a wind speed and direction instrument, a temperature sensor, and a data acquisition system. The system satisfies requirements of the Environmental Protection Agency (EPA), the Texas Natural Resource Conservation Commission (TNRCC), Trinity University, and Dr. Fred Loxsom, the system end-user. The prototype design for this project was developed based on the requirements of all involved parties, and greatly influenced by cost and ease of implementation.

The final design includes the following components:

  • Ozone Monitor - Dasi bi 1008 AH

  • Nitrogen Oxide Analyzer-Monitor Labs Model ML 9841A

  • Ground-Based Ultraviolet Radiometer System - YES UVB-1

  • Wind Instruments -Texas Electronics Inc. Model 2010/2011

  • Thermistor- Texas Instruments Model 837

  • Heat Tape/Temperature Controller - Thermolyne

  • Teflon Air Intake Lines - Bevco

  • Data Acquisition System (Detailed list in Section 5)

  • Dell Pentium II 400 MHz Processor

The location of the system component was selected to accommodate the EPA requirements within the physical limits on the roof of the MMS building, which is the system location imposed by the system end-user, Dr. Fred Loxsom. The selected location of the meteorological instrumentation is above the surface of the roof and thus requires a 9.5-foot tall vertical support tower. The tower is made from ¾-inch 1040 carbon steel pipe and is anchored to a catwalk for structural support.

Condensation in the air sample lines connected to the ozone monitor and nitrogen oxide analyzer, which could corrupt the ozone and nitrogen oxide data, is prevented by the use of heat tape wrapped around the lines. The heat tape is maintained at an elevated temperature using a temperature controller. Pipe insulation as well as aluminum foil encases the heat tape and sample lines to increase conduction and minimize heat loss, respectively, in order to induce optimum performance.

The control system and the data acquisition system (DAQ) integrate multiple independent Lab View modules to acquire, process, store, and transmit all relevant weather, ozone, and nitrogen oxide data. The end-user is able to control all instrumentation through one graphical interface module. This system runs on a computer already present in Dr. Loxsom's lab.

At the termination of the project, the following steps will need to be taken to make the station fully operational: the ozone monitoring station requires testing the instrumentation against standards to validate measurements, calibration of the temperature controller to determine the operational dial setting, and the final set-up for data transfer to the TNRCC main network, which may require integration of a data logger as well as a router into the system.


Comments

Engineering Design VIII, Spring 2001

Faculty Advisor: Dr. Diana Glawe

Special Project Advisor: Dr; Fred Loxsom

Project Administrator: Dr. J. Paul Giolma

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