One-month continuous ozone (O3) measurement at a high-elevation and highly forested site discovered elevated O3 levels in the free troposphere (FT) over central China. O3 injuries to the old-growth forest in the study region were expected. Local emissions in central China overwhelmed regional impacts in building up the concentrations of most air pollutants, same for the ozone formation potential of VOCs. Nitrogen dioxide dominated the in-situ O3 production. It facilitated the transformation of peroxyl radicals to hydroxyl radical (OH), instead of consuming OH. VOCs showed little impact on in-situ O3 production, and accounted for net consumption of OH, with isoprene as the most predominant OH depleting species. This study fills the gaps in FT O3 observation and photochemistry in central China, and provides hints that O3 pollution in central China was more attributed to local emissions.