April 1999, Volume 9, Issue 2, Pages 143 – 149

Article

Initial field evaluation of the Harvard active ozone sampler for personal ozone monitoring ALISON S. GEYH1, PAUL T. ROBERTS2, FREDERICK W. LURMANN2, BASTIAN M. SCHOELL2 & EDWARD L. AVOL3 1Department of Environmental Health, Harvard University, School of Public Health, Boston, Massachusetts     2Sonoma Technology Incorporated, Petaluma, California     3Department of Preventive Medicine, University of Southern California, Los Angeles, California     Correspondence to: ALISON S. GEYH , Health Effects Institute, Cambridge, MA 02139. Tel.: (617)876-6700. Fax: (617)876-6709.

Keywords

active;   children;   collection;   ozone;   passive;   personal;   rate;   sampler

Abstract

Assessing personal exposure to ozone has only been feasible recently with the introduction of passive ozone samplers. These devices are easy to use, but changes in air velocity across their collection surfaces can affect performance. The Harvard active ozone sampler (AS) was developed in response to problems with the passive methods. This active sampler has been tested extensively as a microenvironmental sampler. To test for personal sampling, 40 children attending summer day-camp in Riverside, California wore the active ozone sampler for approximately 2.6 h on July 19 and 21, 1994, when ozone concentrations were about 100 ppb and 140 ppb, respectively. The children spent 94-100% of the sampling period outside, staying within a well-defined area while participating in normal camp activities. Ambient ozone concentrations across this area were monitored by two UV photometric ozone monitors. The active sampler was worn in a small backpack that was also equipped with a passive ozone sampler. Device precision, reported as the percent difference between duplicate pairs of samplers, was ±3.7% and ±4.2% for the active and passive samplers, respectively. The active sampler measured, on average, 94.5±8.2% of the ambient ozone while the passive samplers measured, on average, 124.5±18.8%. The samplers were worn successfully for the entire sampling period by all participating children.

Received 9 February 1998; Accepted 18 September 1998

^© Macmillan Publishers Ltd 1997