Airborne Measurements of Agricultural Volatile Organic Compound Fluxes in the San Joaquin Valley (California)
Abstract
The San Joaquin Valley is a major agricultural production area in California, with various crops as well as large cattle and dairy farms. It also is a region with frequent nonattainment of US air quality standards for ozone and particulate matter (PM). Emission inventories of agricultural volatile organic compounds (VOCs) as important precursors to ozone and PM are subject to large uncertainties, and deposition rates of many oxidation products are poorly constrained. We measured a wide range of VOCs by Vocus PTR-ToF-MS from a Twin Otter aircraft over the San Joaquin Valley in order to better understand VOC sources and sinks in the region. The flights covered ~6000 km of transects between Bakersfield, Visalia and Fresno, and were conducted in June 2021 as part of the RECAP-CA (Re-Evaluating the Chemistry of Air Pollutants in CAlifornia) campaign. By flying slowly (50-60 m/s) at a low altitude of ~400 m above ground, we were able to map VOC sources and sinks with ~ 2 km spatial resolution using Airborne Eddy Covariance with a wavelet analysis approach. Here we show fluxes of important agricultural VOCs with a focus on dairy and cattle farm emissions.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.B54D..03P