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Volatile organic compounds (VOCs) are the precursors of forming ozone (O 3 ) and fine particulate matter (PM 2.5 ). Accurate estimates of biogenic VOC (BVOC) emissions is essential for understanding the formation mechanism of O 3 and PM 2.5 pollution and precise reduction on anthropogenic emissions and thereby mitigating O 3 and PM 2.5 pollution. To gain comprehensive knowledge of BVOC emissions and improve the accuracy of their estimation, this study reviewed localized national, regional, and municipal emission estimations in China. From their comparisons, BVOC emission characteristics and deficiencies in the inventory compilation methodology were also investigated. The estimated BVOC emissions in China ranged between 10 and 58.9 Tg yr -1 and 10.9-18.9 Tg C yr -1 , with diverse contributions for different BVOC categories. The simulated historical and future BVOC emissions exhibited an increasing trend. The uncertainty of the BVOC estimates was mainly from the applications of incomplete emission models, less localized accurate emission factors, deficient vegetation cover information, and low-resolution meteorological data in the inventory compilation. The regional and municipal BVOC emission inventories mainly focused on the Beijing-Tianjin-Hebei, Pearl River Delta, Sichuan Basin, and Yangtze River Delta regions, as well as the cities therein. For the same area, different studies reported diverse BVOC emissions by a maximum of two orders of magnitude. There is usually a lack of basic data with more detailed investigations and higher precision for estimation of BVOC emissions. By summarizing the measurements on terrestrial and marine BVOC emission fluxes, they are mainly focused on the Guangdong, Zhejiang and Jiangxi provinces, and Yellow Sea, East China Sea, and South China Sea, respectively. Expanding the temporal and spatial scales of observations is encouraged to enhance our understanding on the emissions and improve the emission estimates., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

China suffered from serious and elevated ozone (O 3 ) pollution during 2014-2020. O 3 exposure increased with W126, a biologically based cumulative exposure index, at a rate of 1.738 ppm-hr yr -1 . MEGAN3.1 was applied to estimate biogenic volatile organic compound (BVOC) emissions and their response to O 3 pollution in China by quantifying species responses to O 3 stress. In 2020, China's BVOC emissions were 23.26 Tg when considering the effects of O 3 pollution, which was 1.7 % higher than that without O 3 stress. Isoprene, monoterpenes, sesquiterpenes, and other VOC emissions changed by -1.0 %, 1.4 %, 15.5 %, and 2.7 %, respectively. The stimulated BVOC emissions were mainly focused on the North China Plain (NCP) and a partial area of the Tibetan Plateau, which increased by >45 %. Changes in monthly emissions differed, with the greatest increase, 181 tons (3.25 %), in August. The seasonal patterns for the impacts of O 3 pollution were also distinguished spatially. The elevated O 3 exposure caused BVOC emission increases of 104.7 Gg yr -1 during 2014-2020, with isoprene, monoterpenes, sesquiterpenes, and other VOCs contributing -18.6 %, 27.5 %, 40.4 %, and 50.8 %, respectively. The greatest increase in emissions appeared on the NCP and eastern and central China, with annual increases of >100 tons per grid (36 km × 36 km). The interannual variations in BVOC emissions also displayed different seasonal patterns., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Soil drought and nitrogen (N) deposition can influence the biogenic volatile organic compound (BVOC) emissions and thereby their ozone (O 3 ) and secondary organic aerosol (SOA) formation. This study addressed their single and combined effects on BVOC emissions of Pinus thunbergii by laboratory simulation experiments. The results showed that light drought (LD, 50% soil volumetric water content (VWC)) stimulated isoprene, monoterpene, sesquiterpene, and total BVOC emissions, while moderate drought (MD, 30% and 40% VWC) and severe drought (SD, 10% and 20% VWC) inhibited their emissions (except for sesquiterpene in 20% VWC). N deposition decreased other VOC emissions and increased isoprene and sesquiterpene emissions. Total BVOCs and monoterpene were stimulated in low N deposition (LN, 2 g N/(m 2 ·yr)) and inhibited in moderate (MN, 5 g N/(m 2 ·yr)) and high N deposition (HN, 10 g N/(m 2 ·yr)). Under combined treatment of soil drought and N deposition, total BVOC, monoterpene, and other VOC emissions were inhibited, sesquiterpene had no significant change, and isoprene emission was inhibited in MD combined treatment but promoted in SD. The O 3 formation potential (OFP) and SOA formation potential (SOAP) from the changed BVOC emissions were calculated, OFP and SOAP of BVOC emissions and their compositions varied significantly among the treatments. Our study provided theoretical basis for assessing the impact of climate change and atmospheric pollution on BVOC emissions and their contribution to the formation of secondary atmospheric pollution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The aim of this study was to evaluate the effect of edible oil on the volatile aroma profile and storage quality of garlic paste, and to explore the underlying mechanisms. The administration of blend oil at 40 °C in a garlic to oil ratio of 1.8 had a higher overall acceptance by affective sensory test. Compared with the original garlic paste, the sensory aroma profile of the oil-immersed garlic paste was characterized by suppressed pungency, garlic scent and garlic odor, and enhanced oil scent. SPME-GC-MS and HS-GC-IMS showed that the application of blend oil caused great changes in the level of some compounds, which could explain its role in the oil-immersed garlic paste. Furthermore, the blend oil also reduced the growth rate of the total number of colonies and browning intensity, and inhibited the loss of allicin. Therefore, the application of blend oil in garlic paste improved the sensory aroma and delayed the deterioration of the product quality., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Biogenic volatile organic compounds (BVOCs), particularly terpenoids, can significantly drive the formation of ozone (O 3 ) and secondary organic aerosols (SOA) in the atmosphere, as well as directly or indirectly affect global climate change. Understanding their emission mechanisms and the current progress in emission measurements and estimations are essential for the accurate determination of emission characteristics, as well as for evaluating their roles in atmospheric chemistry and climate change. This review summarizes the mechanisms of terpenoid synthesis and release, biotic and abiotic factors affecting their emissions, development of emission observation techniques, and emission estimations from hundreds of published papers. We provide a review of the main observations and estimations in China, which contributes a significant proportion to the total global BVOC emissions. The review suggests the need for further research on the comprehensive effects of environmental factors on terpenoid emissions, especially soil moisture and nitrogen content, which should be quantified in emission models to improve the accuracy of estimation. In China, it is necessary to conduct more accurate measurements for local plants in different regions using the dynamic enclosure technique to establish an accurate local emission rate database for dominant tree species. This will help improve the accuracy of both national and global emission inventories. This review provides a comprehensive understanding of terpenoid emissions as well as prospects for detailed research to accurately describe terpenoid emission characteristics worldwide and in China., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

An accurate local biogenic volatile organic compound (BVOC) emission inventory in Shandong Province is crucial for air pollution control in Shandong and the Beijing-Tianjin-Hebei region, China. We estimated the multi-year isoprenoid emissions from natural vegetation in Shandong Province at a spatial resolution of 4 km × 4 km using the MEGAN2.1 model. A new vegetation classification with 23 plant species/types was developed, and emission factors were determined based on the most detailed and localized investigation and statistics. Isoprene, monoterpene, and sesquiterpene emissions in 2018 were 325.6, 18.2, and 7.9 Gg (mass of carbon), respectively. β-Pinene, α-pinene, ocimene, farnescene, and caryophyllene were the dominant monoterpenes and sesquiterpenes. Broadleaf trees contributed the most to total emissions, particularly poplar, which had the highest emission rates. Wheat also had higher emissions owing to its large coverage. Isoprenoid emissions displayed an inverted "U" pattern when plotted against the months and peaked in summer. Emissions were concentrated in the western and southeastern areas with emission intensities of >10 ton/grid, including Dezhou, Liaocheng, and Rizhao cities. During 1981-2018, isoprenoid emissions experienced a rapid increase from 12.0 to 351.7 Gg, at a rate of 11.20 Gg/yr. Isoprene had the highest enhancement rate of 10.72 Gg/yr. The most rapid increase was observed in the northwestern cities Dezhou and Liaocheng, and the southeastern cities Rizhao, at an average rate of >100 kg/yr, even >500 kg/yr in some areas. The high emissions and their continued increase should be considered when studying the prevention and control of regional air pollution and making policies in China., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Accurate biogenic volatile organic compound (BVOC) emission estimations are essential for developing effective air pollution control measures. Chinese BVOC emissions were calculated at a spatial resolution of 36 km × 36 km for 2008-2018 using the Model of Emissions of Gases and Aerosols from Nature. A statistical method was developed to obtain more accurate emission rates based on large numbers of observations from China and other countries. The most detailed and accurate vegetation investigations at high resolutions were used to determine the distributions of leaf biomass and coverage for 82 vegetation species and types. The results show that the national BVOCs emissions in China in 2018 were large, 58.89 Tg, with isoprene, monoterpene, sesquiterpene, and other VOCs accounting for 63.60%, 11.35%, 2.18%, and 22.87% of the emissions, respectively. Broadleaf trees exhibited the largest isoprene and total BVOC emissions. The biogenic emissions and compositions displayed strong seasonal variations, and isoprene was significantly more sensitive to seasonality. The emissions were concentrated in the Greater Khingan Mountain, Changbai Mountain, Qinling Mountain, southeast and southwest forest areas, and Hainan Province because of their larger distributions of broadleaf trees with higher emission potentials. During 2008-2018, BVOC emissions increased by 20.18% at an annual rate of 2.03%, and isoprene exhibited the greatest enhancement of 32.67%, which was primarily due to the increase in leaf biomass. The regions with the largest growth were distributed in the Greater Khingan and Changbai Mountains, and the Sichuan, Hunan, and Hubei Provinces, which was primarily the result of the substantial increase in volumes of trees with higher emission rates. The uncertainty of our estimates was evaluated by comparing the applied basal emission factors, vegetation coverages, meteorological data, and emission algorithms from previous studies, and it was estimated to be approximately -36.5-4.6%., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Biogenic volatile organic compounds (BVOCs) are important precursors of forming ozone (O3) and secondary organic aerosols (SOAs), which have important impacts on air quality and climate change. Using a literature search, this review analyzed the concentration levels and spatial-temporal distributions of isoprene and monoterpene in the atmosphere in China, mainly from biogenic emissions, and estimated their impact on O3 and SOA generation. The existing observations were mainly in the Beijing–Tianjin–Hebei region, the Pearl River Delta region, central China, and in remote mountainous areas. The results showed that isoprene is the dominant component of BVOCs in the atmosphere, and its ambient concentration is much higher than monoterpene. The site-average concentrations of isoprene and monoterpene were 0.004–3.80 and 0.0003–6.31 ppb, respectively. At vegetation sites, the concentrations of isoprene and monoterpene were 0.006–3.80 and 0.007–6.31 ppb, respectively, whereas they were 0.004–2.70 and 0.0003–1.10 ppb at urban sites. For urban sites, the higher concentrations of annual isoprene occurred mainly in several central megacities, in the Sichuan–Chongqing region, and in southern regions. For vegetation sites, higher concentrations mainly occurred in southern regions. Ambient concentrations of BVOCs in the western region were the lowest for both urban and vegetation sites. Both isoprene and monoterpene showed higher concentrations in summer. The potential of isoprene and monoterpene to form O3 was 0.05–57.21 and 0.003–72.35 ppb, while that which form SOA was 0.0002–0.21 and 0.0006–10.46 µg/m3, respectively. For urban sites, the average annual O3 formation potential (OFP) by isoprene and monoterpene was 8.70 and 2.58 ppb, respectively, and their SOA formation potential (SOAP) was 0.03 and 0.37 µg/m3, respectively. For vegetation sites, it was 7.95 and 5.31 ppb and 0.03 and 0.75 µg/m3, respectively. The annual average contributions of isoprene and monoterpene to O3 and SOA formation were higher in the Beijing–Tianjin–Hebei region, Pearl River Delta region, and central China, which experience severe air pollution in China. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) emitted by plant foliage play an important role in ozone (O3) and secondary organic aerosol (SOA) formation. Their emissions can be influenced by the leaf age. We explored the VOCs emissions and their effects on the formation of O3 and SOA from plant foliage in different ages. VOCs emissions from the young, mature, and senescent leaves of Ginkgo biloba, Ligustrum lucidum, and Forsythia suspensa were measured using the dynamic enclosure system and the TD–GC–MS technique. Based on the emission rates of quantified compounds, their potential to form O3 and SOA was estimated. Results showed that there were significant differences in the VOCs emission rate and their composition among leaves in different ages. The emission rate of the total VOCs by young leaves was the highest, while the lowest by senescent leaves. Monoterpenes were the dominant VOCs category, and isoprene emission had the lowest contribution for the leaves at each age. With increasing leaf age, the proportion of monoterpenes emission increased, and the proportion of sesquiterpenes decreased. The variations of isoprene and other VOCs were different. The potentials of total VOCs, isoprene, monoterpenes, sesquiterpenes, and other VOCs to form O3 (OFP) and SOA (SOAP) varied significantly among leaves at different ages. The total OFP and SOAP were the highest by young leaves, while the lowest by senescent leaves. With increasing leaf age, the contribution of monoterpenes to OFP and SOAP also increased, while that of sesquiterpenes decreased. Our study will provide support for the more accurate parameterization of the emission model and help to understand the VOCs emissions and study the precise prevention and control of complex air pollution at different times. [ABSTRACT FROM AUTHOR]

Biogenic volatile organic compounds (BVOCs) emitted by plants play a crucial role in ozone (O 3) formation. Avoiding urban air quality trade-offs of urban greening involves selecting low-emission and O 3 forming potential (OFP) plants. Using a dynamic enclosure system and the TD-GC-MS technique, we measured BVOC emissions from 47 common urban greening plant species in northern China. The potential to form O 3 was estimated based on the emission quantification of 63 compounds and their maximum incremental reactivity (MIR) values. The results indicated that isoprene and most of monoterpene dominated BVOC emissions. Most of the broad-leaved trees were isoprene emitter, whereas needle-leaved and some broad-leaved trees emitted monoterpene and sesquiterpene. Alkene emissions, such as 1-hexene, were relatively low, while Phoebe zhennan exhibited higher aromatics such as m-ethyltoluene. Broad-leaved trees had a higher potential for O 3 generation compared to needle-leaved trees. BVOC emission rates and OFP varied significantly among plant species, ranging from 0.08 to 112.23 μg/(g h) and 0.33–1130.75 μg/(g h), respectively. To minimize BVOC emissions and O 3 pollution, we determined a list of preferred urban greening plants using hierarchical cluster analysis combined BVOC emission rates and OFPs. Based on our findings, we recommend incorporating plants with low BVOC emissions and OFPs, such as Eucommia ulmoides , Firmiana platanifolia , and Cercis chinensis , in future urban greening plans to prevent strengthening O 3 pollution in northern China. [Display omitted] • BVOC emissions of 47 urban greening plant species were measured in northern China. • BVOC emissions and composition, and OFPs differed significantly among plant species. • OFP of a plant was determined by both BVOC emission level and compound composition. • Preferred urban greening plant species were selected by integrating emission and OFP. [ABSTRACT FROM AUTHOR]

Coordinated control of fine particulate matter (PM 2.5) and ozone (O 3) has become a new and urgent issue for China's air pollution control. Biogenic volatile organic compounds (BVOCs) are important precursors of O 3 and secondary organic aerosol (SOA) formation. China experienced a rapid increase in BVOC emissions as a result of increased vegetation biomass. We applied WRF-Chem3.8 coupling with MEGAN2.1 to conduct long-term simulations for impacts of BVOC emissions on O 3 and SOA during 1981–2018, using the emission factors extrapolated by localized emission rates and annual vegetation biomass. In summer 2018, BVOC emissions were 9.91 Tg (in June), which led to an average increase of 8.6 ppb (16.75 % of the total) in daily maximum 8 h (MDA8) O 3 concentration and 0.84 µgm -3 (73.15 % of the total) in SOA over China. The highest contribution to O 3 is concentrated in the Great Khingan Mountains, Qinling Mountains, and most southern regions while in southern areas for SOA. Isoprene has the greatest contribution to O 3 , while monoterpene has the largest SOA production. BVOC emissions have distinguished impacts in different regions. The Chengdu–Chongqing (CC) region has the highest O 3 and SOA generated by BVOCs, while the Beijing–Tianjin–Hebei (BTH) region has the lowest. From 1981 to 2018, the interannual variation of BVOC emissions caused by increasing leaf biomass resulted in O 3 concentration increasing by 7.38 % at an average rate of 0.11 ppb yr -1 and SOA increasing by 39.30 % at an average rate of 0.008 µgm -3 yr -1. Due to the different changing trends of leaf biomass by region and vegetation type, O 3 and SOA show different interannual variations. The Fenwei Plain (FWP), Yangtze River Delta (YRD), and Pearl River Delta (PRD) regions have the most rapid O 3 increment, while the increasing rate of SOA in CC is the highest. BTH has the smallest enhancement in O 3 and SOA concentration. This study will help to recognize the impact of historical BVOC emissions on O 3 and SOA and further provide a reliable scientific basis for the precise prevention and control of air pollution in China. [ABSTRACT FROM AUTHOR]

Biogenic volatile organic compounds (BVOCs) are important drivers of atmospheric chemical composition and accurate model simulations require characterization of the emissions associated with specific vegetation types which is typically determined using enclosure measurements. Static enclosure techniques were used for past BVOC emission measurement studies, especially in the 1960s–1980s, but are no longer widely used because of concerns that the resulting emission rates are not representative. The main advantages of the static approach are the capability for rapid measurements and a lower detection limit that enables the use of less sensitive analytical techniques. We evaluate a version of the static approach which we call the semi-static approach. In order to evaluate the performance of the semi-static approach for BVOCs emission measurements, multiple replicate measurements for different plants were conducted in a laboratory growth chamber using both semi-static and dynamic enclosure techniques. Variability of replicate measurements was calculated and the results from the two techniques were compared. The semi-static technique provided consistent measurements for isoprene but not for α-pinene, β-pinene and other compounds that are stored in leaves. The measured isoprene emission factors were much higher than dynamic measurements. There were a large number of compounds to be detected by dynamic technique that could not be detected by the semi-static technique. But the semi-static technique could still provide qualitative information on categorization of non, low and high emitters for some compounds. • Semi-static method cannot provide consistent measurements for VOCs stored in leaf. • The measured isoprene emission factors are much higher than dynamic measurements. • Semi-static technique can detect fewer compounds than dynamic one. [ABSTRACT FROM AUTHOR]

Soil drought and nitrogen (N) deposition can influence the biogenic volatile organic compound (BVOC) emissions and thereby their ozone (O 3) and secondary organic aerosol (SOA) formation. This study addressed their single and combined effects on BVOC emissions of Pinus thunbergii by laboratory simulation experiments. The results showed that light drought (LD, 50% soil volumetric water content (VWC)) stimulated isoprene, monoterpene, sesquiterpene, and total BVOC emissions, while moderate drought (MD, 30% and 40% VWC) and severe drought (SD, 10% and 20% VWC) inhibited their emissions (except for sesquiterpene in 20% VWC). N deposition decreased other VOC emissions and increased isoprene and sesquiterpene emissions. Total BVOCs and monoterpene were stimulated in low N deposition (LN, 2 g N/(m2·yr)) and inhibited in moderate (MN, 5 g N/(m2·yr)) and high N deposition (HN, 10 g N/(m2·yr)). Under combined treatment of soil drought and N deposition, total BVOC, monoterpene, and other VOC emissions were inhibited, sesquiterpene had no significant change, and isoprene emission was inhibited in MD combined treatment but promoted in SD. The O 3 formation potential (OFP) and SOA formation potential (SOAP) from the changed BVOC emissions were calculated, OFP and SOAP of BVOC emissions and their compositions varied significantly among the treatments. Our study provided theoretical basis for assessing the impact of climate change and atmospheric pollution on BVOC emissions and their contribution to the formation of secondary atmospheric pollution. [Display omitted] • Monoterpene was the dominant BVOCs for P. thunbergii among all the treatments. • BVOC emission was promoted in light drought while suppressed in moderate and severe drought. • Total BVOC and monoterpene rose in low N deposition and reduced in moderate and high N deposition. • Combined treatment inhibited total BVOC, monoterpene, and other VOC emissions. • OFP and SOAP of BVOC emissions varied significantly among the treatments. [ABSTRACT FROM AUTHOR]

To better understand the chemical speciation of volatile organic compounds (VOCs) and their role in ground-level ozone formation in the Beijing-Tianjin-Hebei region, China, measurements of 56 non-methane hydrocarbons (NMHCs) and 12 carbonyls were conducted at three sites in summer. Alkanes were the largest group of NMHCs (>50%), followed by alkenes and aromatics. Acetone was the most abundant carbonyl species (>50%). The OH loss rates (L OH ) of VOCs were calculated to estimate their chemical reactivities. Alkenes played a predominant role in VOC reactivity, among which ethene and propene were the largest contributors. Isoprene contributed 11.61–38.00% of the total reactivity of measured VOCs. Alkenes and aromatics were the largest contributors (47.65–61.53% totally) to the total Ozone Formation Potential (OFP) of measured VOCs based on the observed mixing ratio. Isoprene was the most reactive species, but originated mainly from biogenic emissions. Ethene, m/p-xylene, toluene, propene, o-xylene, and 1-butene were considered to play significant roles in ground-level ozone formation in this region. The OFPs of total measured NMHCs increased by 10.20–22.05% when they were calculated based on the initial mixing ratio. Photochemical losses of hydrocarbons and the secondary formation of carbonyls in this region were also determined. Vehicle exhaust emissions contributed substantially to ambient VOCs. [ABSTRACT FROM AUTHOR]

A method was developed to establish a comprehensive anthropogenic VOC emission inventory in China, in which a four-level source categorization was proposed, and an emission factor determination system together with a reference database were developed. And this was applied to establish VOC emission inventories for the period 2008–2012. Results show China's anthropogenic VOC emissions increased from 22.45 Tg in 2008 to 29.85 Tg in 2012 at an annual average rate of 7.38%, with Shandong, Guangdong, Jiangsu, Zhejiang and Hebei provinces being the largest emitters. Industrial processes, transportation and solvent utilization were the key sources, accounting for 39.3%, 25.6%, and 14.9% of the total emissions in 2012, respectively. Passenger cars, biofuel combustion, coke production, field burning of biomass, and raw chemical manufacturing were the primary VOC sources nationwide. The key sources for each province were different because of the disparate industry and energy structure. China's VOC emissions displayed remarkable spatial variation, with emissions in the east and southeast regions being much larger than in the northwest, and the high emission areas mainly centered in the Bohai Economic Rim, the Yangtze River Delta, the Pearl River Delta and the Sichuan Basin. The size of high emission areas expanded over the period 2008–2012, with heavily polluted city clusters gradually emerging. [ABSTRACT FROM AUTHOR]