Measurement of ambient ozone using a nitrite-coated filter

Abstract

Standard ozone monltorlng technlques utlllze large, heavy, and expenslve Instruments that are not easlly adapted for personal or mlcroenvlronmental monltorlng. For largescale monltorlng projects, where spatlal varlatlons of a pollutant and human exposure assessments are of Interest, passlve sampllng devlces can provide the methodology to meet monltorlng and statlstlcal goals. Recently we developed a coated fllter for ozone collectlon that we used In a commerclally available passive sampllng devlce. Results from the ozone sampler valldatlon tests are presented. The paoslve ozone sampler used In fleld and laboratory experlments consists of a badge clip supportlng a barrel-shaped body whlch contalns two coated glass flber fllters. The principal component of the coatlng is nltrlte Ion, which In the presenceof ozone Is oxldlzed to nltrate Ion on the fllter medlum, N01-+ 0 3 -NOS-+ 0 2 .After sample collectlon, the filters are extracted wlth ultrapure water and analyzed for nltrate Ion by Ion chromatography. The results from laboratory and fleld valldatlon tests lndlcate excellent agreement between the paslve method and standard ozone monltorlng technlques. We have determined that relative humldlty (ranglng from 10 to 80%) and temperature (ranglng from 0 to 40 "C) at typlcal amblent ozone levels (40-100 ppb) do not Influence sampler performance. Face veloclty and sampler orlentation with respect to wlnd dlrectlon affected the sampler's collectlon rate of ozone. By using a protectlve cup which acts as both a wlnd screen and a raln cover, we were able to obtain a constant collectlon rate over a wlde range of wlnd speeds.

Interpersonal and daily variability of personal exposures to nitrogen dioxide and sulfur dioxide

“…An ozone passive sampler (Koutrakis et al, 1993) was modified to collect SO 2 . The filters were cleaned with the following series of solutions (with ultra-pure water rinses after each reagent): (a) concentrated HNO 3 , (b) chromic acid, and (c) concentrated HCl 10 N NaOH.…”

The Harvard Southern California Chronic Ozone Exposure Study: assessing ozone exposure of grade-school-age children in two Southern California communities.

“…Small lightweight passive ozone exposure monitors, however, are now available. These monitors make personal and microenvironmental monitoring feasible (9)(10)(11). The Harvard passive ozone sampler is one such device that depends on the reaction between ozone and the nitrite ion for ozone concentration measurement (11).…”

Hydrogen sulfide measurements in air by passive/diffusive samplers and high-frequency analyzer: A critical comparison

“…The detection limit of this method, for 1 h exposure at 25 C, is 25 mg/m 3 (corresponding to a mass, m, of 0.105 mg), whereas the uncertainty (2s) is ±8.7% (Fondazione Maugeri, 2007). However, recent studies (Koutrakis et al, 1993;Gair and Penkett, 1995;Brown, 2000;Krupa and Legge, 2000;Pennequin-Cardinal et al, 2005) pinpointed that weather conditions (e.g. humidity, temperature, wind speed and direction) can affect the efficiency of the Radiello ® traps, although a reliable evaluation of their effective influence on passive H 2 S measurements is not available.…”