A device to validate concentration measured by direct reading instruments for aerosols

ii To: My parents Khalid and Sarah for their never ending support. My wife Alaa for her encouragement, patience, and believe in me. My children Khaled, Ahmad, and Sarah for bringing joy to my life. iii ACKNOWLEDGMENTS I would like to thank my advisor Dr. Thomas Peters for his support and guidance. I would also like to thank my committee members Dr. Patrick O'Shaughnessy and Dr. Renée Anthony for their support and advice. Also, I would like to thank Kuwait Public Authority for Applied Education and Training (PAAET) and the College of Health Sciences for sponsoring my graduate studies. Finally, I would like to thank my parents Khalid and Sarah, my wife Alaa, and my children Khaled, Ahmad, and Sarah for being the best part of my life. iv ABSTRACT Direct reading instruments (DRIs) are popular devices for measuring aerosols because they provide rapid on-site measurement of particle size and/or concentration. However, the output of DRIs may drift over time requiring frequent manufacturer calibration. Given the possibility of drift, the output of DRIs should ideally be verified to ensure proper response before and after field use. Methods for verifying the output of DRIs particle size reading are available for use in laboratory and field. However, methods for verifying the DRIs concentration reading are complex and often use of stationary installations that are not suited for field work. The objective of this study was to develop a verification device that can be used in the field to verify the output of DRIs for measuring aerosol concentration. The new device uses a nebulizer that produces aerosols through vibrating mesh technology. This vibrating mesh nebulizer (VMN) uses only electrical input to generate aerosols and does not require compressed air. The verification device was able to produce stable output of aerosols at low concentrations (0.2 mg/m 3 to 1.2 mg/m 3). It was also possible to produce different concentration levels of aerosol by changing the electrical current to the VMN. The verification device was used to monitor and validate the output of a condensation particle counter and a photometer. Results showed that both instruments having valid output and did not require manufacture calibration. The verification device made it possible to monitor and verify the output of two DRIs. This was achieved by generating reproducible aerosol output with specific composition. This verification device presents a practical method to verify the concentration output of DRIs for …