Comparison of ozone measurement methods in biomass burning smoke: an evaluation under field and laboratory conditions

Abstract

Abstract. In recent years wildland fires in the United States have had significant impacts on local and regional air quality and negative human health outcomes. Although the primary health concerns from wildland fires come from fine particulate matter (PM2.5), large increases in ozone (O3) have been observed downwind of wildland fire plumes (DeBell et al., 2004; Bytnerowicz et al., 2010; Preisler et al., 2010; Jaffe et al., 2012; Bytnerowicz et al., 2013; Jaffe et al., 2013; Lu et al., 2016; Lindaas et al., 2017; McClure and Jaffe, 2018; Liu et al., 2018; Baylon et al., 2018; Buysse et al., 2019). Conditions generated in and around wildland fire plumes, including the presence of interfering chemical species, can make the accurate measurement of O3 concentrations using the ultraviolet (UV) photometric method challenging if not impossible. UV photometric method instruments are prone to interferences by volatile organic compounds (VOCs) that are present at high concentrations in wildland fire smoke. Four different O3 measurement methodologies were deployed in a mobile sampling platform downwind of active prescribed grassland fire lines in Kansas and Oregon and during controlled chamber burns at the United States Forest Service, Rocky Mountain Research Station Fire Sciences Laboratory in Missoula, Montana. We demonstrate that the Federal Reference Method (FRM) nitric oxide (NO) chemiluminescence monitors and Federal Equivalent Method (FEM) gas-phase (NO) chemical scrubber UV photometric O3 monitors are relatively interference-free, even in near-field combustion plumes. In contrast, FEM UV photometric O3 monitors using solid-phase catalytic scrubbers show positive artifacts that are positively correlated with carbon monoxide (CO) and total gas-phase hydrocarbon (THC), two indicator species of biomass burning. Of the two catalytic scrubber UV photometric methods evaluated, the instruments that included a Nafion® tube dryer in the sample introduction system had artifacts an order of magnitude smaller than the instrument with no humidity correction. We hypothesize that Nafion®-permeating VOCs (such as aromatic hydrocarbons) could be a significant source of interference for catalytic scrubber UV photometric O3 monitors and that the inclusion of a Nafion® tube dryer assists with the mitigation of these interferences. The chemiluminescence FRM method is highly recommended for accurate measurements of O3 in wildland fire plume studies and at regulatory ambient monitoring sites frequently impacted by wildland fire smoke.

A Collection of Airborne Measurements and Analyses of Trace Gases Emitted From Multiple Fires in California

“…This technique has been shown to be free of interferences in aged wildfire plumes with ≤800 ppb CO (Gao & Jaffe, 2017). It is also the method found by Long et al (2021) to have a relatively small interference (i.e., 1.5-3 ppb O 3 (ppm CO) −1 ) compared to our calibration uncertainly (±3 ppbv), indicating that a statistically robust interference would be present only in situations when sampling well in excess of 1,000 ppb CO. Unfortunately CO measurements are not available in the AJAX payload, but the visibility, airspace, and safety limitations of the AJAX flight plans require operations outside the dense plume.…”

Gaseous ozone to preserve quality and enhance microbial safety of fresh produce: Recent developments and research needs

“…Nevertheless, in the present manuscript, ppm is replaced with μl/L. Similarly, there are many ways to measure gaseous ozone, including detector tubes based on oxidation of indigo by ozone resulting in a white color, the iodine method based on reaction with KI, UV photometric method, ozone meters using chemiluminescence or semiconductor sensors, and the trans-stilbene method based on reaction with olefins (Long et al, 2021) (https://www. osha.gov/dts/sltc/methods/inorganic/id214/id214.pdf).…”

Chemical characterization of prescribed burn emissions from a mixed forest in Northern Michigan

“…29–31 These values depend on vegetation, location, and meteorological conditions underscoring the importance of extending laboratory measurements to a wide range of fire environments. 19–21,32 Field smoke measurements have been carried out through stationary 15,17 and mobile 33,34 ground-based methods, as well as airborne studies. 20,23,35,36 Stationary measurements have primarily occurred in the western and southeastern United States, integrating multiple types of vegetation representative of different forest ecosystems, with results that differed from laboratory measurements of similar vegetation.…”

“…20,23,35,36 Stationary measurements have primarily occurred in the western and southeastern United States, integrating multiple types of vegetation representative of different forest ecosystems, with results that differed from laboratory measurements of similar vegetation. 20,23,35,36 Mobile platforms can measure pollutants directly downwind of fresh biomass burning plumes from prescribed burns, 34 and map the distribution of gas and particle emissions across local communities. 37 Results from stationary and mobile field campaigns have been compiled in emission inventories, aiding in the development of fire and smoke models.…”