TY - JOUR
T1 - Atmospheric aerosol measurements by cavity ringdown turbidimetry
AU - Thompson, Jonathan E.
AU - Nasajpour, Habib D.
AU - Smith, Benjamin W.
AU - Winefordner, James D.
N1 - Funding Information:
The authors would like to thank NSF and the University of Florida Engineering Research Center for Particle Science and Technology for financial support and use of the Aerosizer instrument. We also extend our gratitude to Prof. August Miller for providing MIETAB.
PY - 2003/3/1
Y1 - 2003/3/1
N2 - We have investigated monitoring the ambient air extinction coefficient as a sensitive indicator of micrometer sized airborne particles through cavity ringdown spectroscopy (CRDS) at 2 wavelengths. Scatter and absorption of light by the airborne particles induced a measureable decrease in the ringdown decay time of our ringdown cell. When a copper vapor laser operating at 8-10 kHz was employed and 1,500 individual ringdowns were averaged on an oscilloscope, minimal detectable extinction coefficients of 10-6 m-1 could be achieved. We have used our ringdown instrument to detect a correlation between the observed ringdown extinction coefficient and particulate mass concentrations (μg/m3 of air). The correlation we have observed allows estimation of suspended mass concentrations in a matter of minutes, rather than a sampling time of several hours or days encountered in traditional gravimetric approaches. Additionally, we have constructed a variable cut diameter inertial impactor for use with our ringdown system. By varying the cut diameter while making ringdown measurements, it was possible to extract a size resolved extinction spectrum of ambient atmospheric aerosol in a matter of minutes.
AB - We have investigated monitoring the ambient air extinction coefficient as a sensitive indicator of micrometer sized airborne particles through cavity ringdown spectroscopy (CRDS) at 2 wavelengths. Scatter and absorption of light by the airborne particles induced a measureable decrease in the ringdown decay time of our ringdown cell. When a copper vapor laser operating at 8-10 kHz was employed and 1,500 individual ringdowns were averaged on an oscilloscope, minimal detectable extinction coefficients of 10-6 m-1 could be achieved. We have used our ringdown instrument to detect a correlation between the observed ringdown extinction coefficient and particulate mass concentrations (μg/m3 of air). The correlation we have observed allows estimation of suspended mass concentrations in a matter of minutes, rather than a sampling time of several hours or days encountered in traditional gravimetric approaches. Additionally, we have constructed a variable cut diameter inertial impactor for use with our ringdown system. By varying the cut diameter while making ringdown measurements, it was possible to extract a size resolved extinction spectrum of ambient atmospheric aerosol in a matter of minutes.
UR - http://www.scopus.com/inward/record.url?scp=0037367911&partnerID=8YFLogxK
U2 - 10.1080/02786820300942
DO - 10.1080/02786820300942
M3 - Article
AN - SCOPUS:0037367911
VL - 37
SP - 221
EP - 230
JO - Aerosol Science and Technology
JF - Aerosol Science and Technology
SN - 0278-6826
IS - 3
ER -