It is well known from previous research that planting more vegetation reduces more air pollution in cities; however, planting additional vegetation would limit the space for urban development. Therefore, the suggestion on better planting of vegetation for maximum utility in air pollutant reduction. We therefore proposed a hypothetical method, based on the temporal matches, that vegetation supply for air purification is sufficient, between normalized vegetation and air pollution dynamic in a year, for estimating the gap between urban air pollution and urban vegetation that can be used for air pollutant reduction and further preliminarily practiced the method with vegetation indicator of the normalized difference vegetation index (NDVI) and the major pollutants of fine and coarse particulate matters (PM_2.5 and PM₁₀) in a year. We found that cities in East and Central China had relatively high-level urban vegetation throughout the growing season. However, cities with medium and low PM_2.5 concentrations and low PM₁₀ concentrations were most common in China. Both the temporal matches of PM_2.5 and PM₁₀ with vegetation were relatively high in cities with high urbanization levels, particularly in North China, but lower in cites in South China. Our results provided a theoretical method for gap estimation between urban vegetation and air pollutant reduction and demonstrated its preliminary application, which provided both methodology and evidence for understanding the trade-off between urban air pollution and urban greenspace ecoservices.