Characteristics of Volatile Organic Compounds in High-Altitude Counties of the Guanzhong Plain in Summer: Implications for Ozone Pollution Prevention and Control

• • TVOCs concentrations at the two sites were 60.04×10⁻⁹ and 83.28×10⁻⁹, with OVOCs dominating (55.14% and 62.91%), indicating that oxygenated species are the primary VOC fraction in high-altitude counties, which is critical for designing targeted control strategies. • • Industrial sources contributed the largest share (43.2%) to VOC emissions, but site-specific differences (solvent use 30.7% at Government site vs. domestic sources 27.6% at Middle School site) highlight the need for localized emission inventories and tailored abatement measures. • • OFP values were 258.84×10⁻⁹ and 378.04×10⁻⁹ at the two sites, with alkenes and OVOCs as the main contributors, underscoring that these reactive species should be prioritized in ozone mitigation efforts. • • EKMA curves confirmed that the region is VOC-limited, meaning that reducing VOC emissions will effectively lower ozone formation, validating the focus on VOC control in this area.