Urban vegetation in Beijing identified as contributor to ground-level ozone pollution

Research indicates that specific tree species in Beijing, including weeping willows and poplars, emit volatile organic compounds that react with existing pollutants to increase ground-level ozone. While the study highlights a biological source of urban smog, the extent to which this offsets the cooling benefits of the city's canopy remains under investigation. This finding complicates urban planning strategies aimed at mitigating heat islands while simultaneously managing air quality.