Ozone Production in the Soberanes Smoke Haze: Implications for Air Quality in the San Joaquin Valley During the California Baseline Ozone Transport Study

Abstract

The Soberanes Fire burned 53,470 ha (132,127 acres) along the central California coast between 22 July and 12 October 2016, generating dense smoke and a variety of gaseous compounds that drifted eastward into the San Joaquin Valley Air Basin (SJVAB), an “extreme” nonattainment area for ozone (O3). These gases included nitrogen oxides (NOx) and volatile organic compounds, the photochemical precursors of O3. The fire started during the California Baseline Ozone Transport Study, a field campaign that brought aircraft, surface, and remote sensing measurements of O3 and related species to central California. In this paper, we use the California Baseline Ozone Transport Study measurements to assess the impact of the Soberanes Fire on ozone and particulate air quality in the SJVAB. We focus our analysis on 27 July to 2 August when the smoke haze was heaviest and the highest O3 concentrations in the SJVAB during 2016 were recorded. Our analyses suggest that while 40 to 60 ppbv of fire‐generated O3 was transported to the eastern SJVAB in the 1‐ to 3‐km‐altitude range, relatively little smoke or fire‐generated O3 reached the surface in the Visalia area.

Influence of Wildfire on Urban Ozone: An Observationally Constrained Box Modeling Study at a Site in the Colorado Front Range

“…For example, O 3 lidar observations from a site in California's central valley during the coastal Soberanes fire in 2016 showed 40−60 ppbv of transported O 3 enhancement at 1−3 km that did not appreciably mix within the boundary layer to influence surface O 3 . 28 Similarly, aircraft measurements in California during the 2008 ARCTAS campaign found high levels of O 3 aloft from the mixing of urban and fire emissions. 29 Strategies to control urban O 3 production in the absence of smoke impacts have historically centered on analysis of VOC/ NO x sensitivity.…”

“…Boundary layer dynamics, transport, and mixing complicate the observed relationships between fire influence and O 3 . For example, O 3 lidar observations from a site in California’s central valley during the coastal Soberanes fire in 2016 showed 40–60 ppbv of transported O 3 enhancement at 1–3 km that did not appreciably mix within the boundary layer to influence surface O 3 . Similarly, aircraft measurements in California during the 2008 ARCTAS campaign found high levels of O 3 aloft from the mixing of urban and fire emissions …”

Impact of the 2016 Southeastern US Wildfires on the Vertical Distribution of Ozone and Aerosol at Huntsville, Alabama

“…The UAH ozone lidar is affiliated with the Tropospheric Ozone Lidar Network (TOLNet, https://www-air.larc.nasa.gov/missions/TOLNet/). Under a collaborative protocol, the TOLNet lidars have demonstrated their feasibility and capability in fire studies (M. Johnson et al., 2016, 2021; Kuang et al., 2017; Langford et al., 2015, 2020; Reid et al., 2017; Strawbridge et al., 2018) and scientific projects (Gronoff et al., 2019; Leblanc et al., 2018; Sullivan et al., 2019). The continuous profiling of ozone and aerosols provides details missed by isolated measurements and is an asset for model evaluation by coordinating measurements (Langford et al., 2018, 2019).…”

“…The continuous profiling of ozone and aerosols provides details missed by isolated measurements and is an asset for model evaluation by coordinating measurements (Langford et al, 2018(Langford et al, , 2019. In addition, the ultraviolet (UV) backscatter (or extinction) profiles retrieved from ozone lidar can quantify the aerosol variability at the high spatiotemporal resolution, and these measurements serve as a tracer for fire smoke (Kuang et al, 2020;Langford et al, 2020). To our best knowledge, there has been little or no attempt to evaluate CTMs using this range-resolved UV aerosol optical product.…”

The Impacts of Wildfires on Ozone Production and Boundary Layer Dynamics in California's Central Valley

“…Liu et al (2019) Thus, wildfire smoke has two roles in influencing the ABL dynamics: first, by attenuating the solar radiation that reaches the surface it reduces the surface heat fluxes weakening entrainment thereby decreasing the maximum ABL height, and second, it absorbs solar radiation warming the air in the ABL (and above) thereby offsetting the reduced surface heat fluxes in terms of its impact on air temperature. Figure S6 present the backscatter profile from Tunable Optical Profiler for Aerosol and Ozone lidar (TOPAZ) observed during the June -August observed during the California Baseline Ozone Transport Study (Langford et al, 2020;Faloona et al, 2020). The backscatter is seen to be much stronger in ABL, and to a lesser extent above (up to about 2,500 m), during the wildfire periods (left) compared to the background days (right).…”