A statistical approach for estimating representative emission rates of biogenic volatile organic compounds and their determination for 192 plant species/genera in China

Abstract. To obtain more and accurate biogenic volatile organic compound (BVOC) emission rates for more plant species in China and further improve the accuracy of emission rates used in BVOC emission inventories, we conducted field measurements and developed a statistical approach for estimating representative emission rates. We performed field measurements of BVOC emissions from 50 plant species at nine locations in China using our established semi-static enclosure system. The emissions of 102 VOCs, including isoprene, α-pinene, β-pinene, and other VOC species, were analyzed with a custom-built online gas chromatography-mass spectrometry/flame ionization detector system. From the results, broadleaf trees were the greatest potential emitters of isoprene, while needle-leaf trees emitted more pinene. Shrubs had lower isoprene and pinene emission potentials, but higher emission potentials for other VOCs. Methyl methacrylate, isopropylbenzene, isopentane, acetone, ethane, propane, toluene, and xylene were the dominant species among other VOCs, probably with high emission intensities. Therefore, their emissions should be considered in future global and regional BVOC estimation studies. Next, we summarized our field measurements along with reported emission rates from China and abroad. The emission intensity categories were produced based on statistics, with more detailed categories, accurate emission rate intervals and representative rates compared to previous studies. The results showed that the BVOC emission intensities of plants displayed different categories, such as lowest, lower, low, moderate, high, higher, and highest. The isoprene emission rate intervals and representative rates were: lowest, 0.08–0.11 and 0.1 μg C gdw⁻¹ h⁻¹; lower, 0.9–1.3 and 1.0 μg C gdw⁻¹ h⁻¹; low, 5.2–6.5 and 5.8 μg C gdw⁻¹ h⁻¹; moderate, 13.1–15.3 and 14.4 μg C gdw⁻¹ h⁻¹; high, 31.1–37.0 and 33.6 μg C gdw⁻¹ h⁻¹; higher, 67.2–75.1 and 70.1 μg C gdw⁻¹ h⁻¹; and highest, 135.1–157.6 and 142.5 μg C gdw⁻¹ h⁻¹. The monoterpene emission rate intervals and representative rates were: lowest, 0.08–0.11 and 0.1 μg C gdw⁻¹ h⁻¹; lower, 0.17–0.22 and 0.2 μg C gdw⁻¹ h⁻¹; low, 0.5–0.7 and 0.6 μg C gdw⁻¹ h⁻¹; moderate, 1.2–1.5 and 1.4 μg C gdw⁻¹ h⁻¹; high, 2.8–3.3 and 3.0 μg C gdw⁻¹ h⁻¹; and higher, 11.1–14.9 and 12.6 μg C gdw⁻¹ h⁻¹. Using these established emission intervals, we determined the isoprene and monoterpene emission rates for 192 plant species/genera in China, including 30 dominant tree species, 149 shrub and grass genera, and 13 crop species. These estimations would be further improved by integrating larger quantities of rigorous field measurements from China in the future.