scholarly journals Spaceborne evidence for significant anthropogenic VOC trends in Asian cities over 2005-2019

2021 ◽  
Author(s):  
Maite Bauwens ◽  
Bert Verreyken ◽  
Trissevgeni Stavrakou ◽  
Jean-François Müller ◽  
Isabelle De Smedt
Keyword(s):  
Indian Subcontinent ◽  
Action Plan ◽  
Biogenic Emissions ◽  
Anthropogenic Activity ◽  
Anthropogenic Emissions ◽  
Ozone Monitoring Instrument ◽  
Asian Continent ◽  
Near Surface ◽  
Large Cities ◽  
Volatile Organic

Abstract Trends of formaldehyde (HCHO) linked to anthropogenic activity over large cities located in the Asian continent are calculated for the period 2005–2019 using the Quality Assurance for Essential Climate Variables (QA4ECV) dataset from the Ozone Monitoring Instrument (OMI) aboard the Aura satellite. Contributions due to anthropogenic emissions are isolated by applying a correction based on near-surface temperature in order to account for interference from local biogenic emissions. Strong positive trends are derived over the Middle East and the Indian subcontinent (up to 3.6% yr-1 and 2.4% yr-1 respectively) where regulations of anthropogenic non-methane volatile organic compound (NMVOC) emissions are currently limited. Weaker trends are observed over cities located in China, where the air pollution action plan (2013) may have mitigated NMVOC trends early on, but targeted legislature concerning VOC emissions was only recently introduced. HCHO trends for cities located in South and Equatorial Asia are mostly not significant or very uncertain. Cities located in Taiwan and Japan (regions in Asia where legislation has been in place since the early 2000s) display mostly negative trends.

scholarly journals GOME-2 observations of oxygenated VOCs: what can we learn from the ratio glyoxal to formaldehyde on a global scale?

2010 ◽  
Vol 10 (8) ◽  
pp. 19031-19069 ◽  
Author(s):  
M. Vrekoussis ◽  
F. Wittrock ◽  
A. Richter ◽  
J. P. Burrows
Keyword(s):  
Vegetation Index ◽  
Lower Troposphere ◽  
Global Scale ◽  
Photochemical Activity ◽  
Biogenic Emissions ◽  
Anthropogenic Activity ◽  
Anthropogenic Emissions ◽  
Data Sets ◽  
Large Cities ◽  
First Time

Abstract. Collocated data sets of glyoxal (CHO.CHO) and formaldehyde (HCHO) were retrieved for the first time from measurements of the Global Ozone Monitoring Experiment-2 (GOME-2 during the first two years of operation in 2007 and 2008. Both oxygenated Volatile Organic Compounds, OVOC are key intermediate species produced during the oxidation of precursor hydrocarbons. Their short lifetime of a few hours in the lower troposphere links them to emission sources and makes them useful tracers of photochemical activity. The global composite maps of GOME-2 HCHO and CHO.CHO have strong similarities confirming their common atmospheric and/or surface sources. The highest column amounts of these OVOCs are recorded over regions with enhance biogenic emissions (e.g. tropical forests) in South America, Africa and Indonesia). Enhanced OVOC values are also present over areas of anthropogenic activity and biomass burning (e.g. over China, N. America, Europe and Australia). The ratio of CHO.CHO to HCHO, RGF, has been used, for the first time on a global scale, to classify the sources according to biogenic and/or anthropogenic emissions of the precursors; RGF between 0.040 to 0.060 point to the existence of biogenic emissions with the highest values being observed at the highest Enhanced Vegetation Index, EVI. RGFs below 0.040 are indicative of anthropogenic emissions and associated with high levels of NO2. This decreasing tendency of RGF with increasing NO2 is also observed when analyzing data for individual large cities, indicating that it is a common feature. The results obtained for RGF from GOME-2 data are compared with the findings based on regional SCIAMACHY observations showing good agreement. This is explained by the excellent correlation of the global retrieved column amounts of CHO.CHO and HCHO from the GOME-2 and SCIAMACHY instruments for the period 2007–2008.

scholarly journals GOME-2 observations of oxygenated VOCs: what can we learn from the ratio glyoxal to formaldehyde on a global scale?

2010 ◽  
Vol 10 (21) ◽  
pp. 10145-10160 ◽  
Author(s):  
M. Vrekoussis ◽  
F. Wittrock ◽  
A. Richter ◽  
J. P. Burrows
Keyword(s):  
Vegetation Index ◽  
Lower Troposphere ◽  
Global Scale ◽  
Photochemical Activity ◽  
Biogenic Emissions ◽  
Anthropogenic Activity ◽  
Anthropogenic Emissions ◽  
Data Sets ◽  
Large Cities ◽  
First Time

Abstract. Collocated data sets of glyoxal (CHO.CHO) and formaldehyde (HCHO) were retrieved for the first time from measurements of the Global Ozone Monitoring Experiment-2 (GOME-2) during the first two years of operation in 2007 and 2008. Both oxygenated Volatile Organic Compounds, OVOC, are key intermediate species produced during the oxidation of precursor hydrocarbons. Their short lifetime of a few hours in the lower troposphere links them to emission sources and makes them useful tracers of photochemical activity. The global composite maps of GOME-2 HCHO and CHO.CHO have strong similarities confirming their common atmospheric and/or surface sources. The highest column amounts of these OVOCs are recorded over regions with enhance biogenic emissions (e.g. tropical forests in South America, Africa and Indonesia). Enhanced OVOC values are also present over areas of anthropogenic activity and biomass burning (e.g. over China, N. America, Europe and Australia). The ratio of CHO.CHO to HCHO, RGF, has been used, for the first time on a global scale, to classify the sources according to biogenic and/or anthropogenic emissions of the precursors; RGF between 0.040 to 0.060 point to the existence of biogenic emissions with the highest values being observed at the highest Enhanced Vegetation Index, EVI. RGFs below 0.040 are indicative of anthropogenic emissions and associated with high levels of NO2. This decreasing tendency of RGF with increasing NO2 is also observed when analyzing data for individual large cities, indicating that it is a common feature. The results obtained for RGF from GOME-2 data are compared with the findings based on regional SCIAMACHY observations showing good agreement. This is explained by the excellent correlation of the global retrieved column amounts of CHO.CHO and HCHO from the GOME-2 and SCIAMACHY instruments for the period 2007–2008.

scholarly journals Modeling Biogenic and Anthropogenic Secondary Organic Aerosol in China

2016 ◽  
Author(s):  
Jianlin Hu ◽  
Peng Wang ◽  
Qi Ying ◽  
Hongliang Zhang ◽  
Jianjun Chen ◽  
...  
Keyword(s):  
Urban Areas ◽  
Secondary Organic Aerosol ◽  
Temporal Distribution ◽  
Organic Aerosol ◽  
Sensitivity Analyses ◽  
Biogenic Emissions ◽  
Anthropogenic Emissions ◽  
Volatile Components ◽  
Volatile Organic ◽  
Isoprene Oxidation

Abstract. A revised Community Multiscale Air Quality (CMAQ) model with updated secondary organic aerosol (SOA) yields and more detailed description of SOA formation from isoprene oxidation was applied to study the spatial and temporal distribution of SOA in China in the entire year of 2013. Predicted organic carbon (OC), elemental carbon and volatile organic compounds agreed favorably with observations at several urban areas, although the high OC concentrations in wintertime in Beijing were under-predicted. Predicted summer SOA was generally higher (10–15 µg m−3) due to large contributions of isoprene (country average, 61 %). Wintertime SOA was slightly lower and was mostly due to emissions of alkane and aromatic compounds (51 %). Contributions of monoterpenes SOA were relatively constant (8–10 %). Overall, biogenic SOA accounted for approximately 75 % of total SOA in summer, 50–60 % in autumn and spring, and 24 % in winter. Sichuan Basin had the highest predicted SOA concentrations in the country in all seasons, with hourly concentrations up to 50 µg m−3. Approximately half of the SOA in all seasons was due to the traditional equilibrium partitioning of semi-volatile components followed by oligomerization, while the remaining SOA was mainly due to reactive surface uptake of isoprene epoxide (5–14 %), glyoxal (14–25 %) and methylglyoxal (23–28 %). Sensitivity analyses showed that formation of SOA from biogenic emissions was significantly enhanced due to anthropogenic emissions. Removing all anthropogenic emissions while keeping the biogenic emissions unchanged led to total SOA concentrations of less than 1 µg m−3, which suggests that manmade emissions facilitated biogenic SOA formation and controlling anthropogenic emissions would result in reduction of both anthropogenic and biogenic SOA.

scholarly journals Water-Enhanced Flux Changes under Dynamic Temperatures in the Vertical Vapor-Phase Diffusive Transport of Volatile Organic Compounds in Near-Surface Soil Environments

2021 ◽  
Vol 13 (12) ◽  
pp. 6570
Author(s):  
Asma Akter Parlin ◽  
Monami Kondo ◽  
Noriaki Watanabe ◽  
Kengo Nakamura ◽  
Mizuki Yamada ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Vapor Phase ◽  
Inverse Correlation ◽  
Diffusive Transport ◽  
Near Surface ◽  
Voc Emissions ◽  
Transport Behavior ◽  
Volatile Organic

The quantitative understanding of the transport behavior of volatile organic compounds (VOCs) in near-surface soils is highly important in light of the potential impacts of soil VOC emissions on the air quality and climate. Previous studies have suggested that temperature changes affect the transport behavior; however, the effects are not well understood. Indeed, much larger changes in the VOC flux under in situ dynamic temperatures than those expected from the temperature dependence of the diffusion coefficients of VOCs in the air have been suggested but rarely investigated experimentally. Here, we present the results of a set of experiments on the upward vertical vapor-phase diffusive transport of benzene and trichloroethylene (TCE) in sandy soils with water contents ranging from an air-dried value to 10 wt% during sinusoidal temperature variation between 20 and 30 °C. In all experiments, the flux from the soil surface was correlated with the temperature, as expected. However, the changes in flux under wet conditions were unexpectedly large and increased with increasing water content; they were also larger for TCE, the volatility of which depended more strongly on the temperature. Additionally, the larger flux changes were accompanied by a recently discovered water-induced inverse correlation between temperature and flux into the overlying soil. These results demonstrated that the flux changes of VOCs under dynamic temperatures could be increased by volatilization-dissolution interactions of VOCs with water. Future extensive studies on this newly discovered phenomenon would contribute to a better understanding of the impacts of soil VOC emissions on the air quality and climate.

scholarly journals Enhanced SOA formation from mixed anthropogenic and biogenic emissions during the CARES campaign

2013 ◽  
Vol 13 (4) ◽  
pp. 2091-2113 ◽  
Author(s):  
J. E. Shilling ◽  
R. A. Zaveri ◽  
J. D. Fast ◽  
L. Kleinman ◽  
M. L. Alexander ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Proton Transfer Reaction ◽  
Chemical Mechanism ◽  
Biogenic Emissions ◽  
Anthropogenic Emissions ◽  
Radiation Balance ◽  
Particle Phase ◽  
Aerosol Formation ◽  
Research Aircraft

Abstract. The CARES campaign was conducted during June, 2010 in the vicinity of Sacramento, California to study aerosol formation and aging in a region where anthropogenic and biogenic emissions regularly mix. Here, we describe measurements from an Aerodyne High Resolution Aerosol Mass Spectrometer (AMS), an Ionicon Proton Transfer Reaction Mass Spectrometer (PTR-MS), and trace gas detectors (CO, NO, NOx) deployed on the G-1 research aircraft to investigate ambient gas- and particle-phase chemical composition. AMS measurements showed that the particle phase is dominated by organic aerosol (OA) (85% on average) with smaller concentrations of sulfate (5%), nitrate (6%) and ammonium (3%) observed. PTR-MS data showed that isoprene dominated the biogenic volatile organic compound concentrations (BVOCs), with monoterpene concentrations generally below the detection limit. Using two different metrics, median OA concentrations and the slope of plots of OA vs. CO concentrations (i.e., ΔOA/ΔCO), we contrast organic aerosol evolution on flight days with different prevailing meteorological conditions to elucidate the role of anthropogenic and biogenic emissions on OA formation. Airmasses influenced predominantly by biogenic emissions had median OA concentrations of 2.2 μg m−3 and near zero ΔOA/ΔCO. Those influenced predominantly by anthropogenic emissions had median OA concentrations of 4.7 μg m−3 and ΔOA/ΔCO ratios of 35–44 μg m−3 ppmv. But, when biogenic and anthropogenic emissions mixed, OA levels were enhanced, with median OA concentrations of 11.4 μg m−3 and ΔOA/ΔCO ratios of 77–157 μg m−3 ppmv. Taken together, our observations show that production of OA was enhanced when anthropogenic emissions from Sacramento mixed with isoprene-rich air from the foothills. After considering several anthropogenic/biogenic interaction mechanisms, we conclude that NOx concentrations play a strong role in enhancing SOA formation from isoprene, though the chemical mechanism for the enhancement remains unclear. If these observations are found to be robust in other seasons and in areas outside of Sacramento, regional and global aerosol modules will need to incorporate more complex representations of NOx-dependent SOA mechanisms and yields into their algorithms. Ultimately, accurately predicting OA mass concentrations and their effect on radiation balance will require a mechanistically-based treatment of the interactions of biogenic and anthropogenic emissions.

scholarly journals Temperature-dependence of aerosol optical depth over the southeastern US

2016 ◽  
Author(s):  
Tero Mielonen ◽  
Anca Hienola ◽  
Thomas Kühn ◽  
Joonas Merikanto ◽  
Antti Lipponen ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Land Surface ◽  
Radiative Forcing ◽  
Climate Model ◽  
Biogenic Emissions ◽  
Anthropogenic Emissions ◽  
Model Estimate ◽  
Model Simulations ◽  
Southeastern Us ◽  
Biogenic Aerosols

Abstract. Previous studies have indicated that summer-time aerosol optical depths (AOD) over the southeastern US are dependent on temperature but the reason for this dependence and its radiative effects have so far been unclear. To quantify these effects we utilized AOD and land surface temperature (LST) products from the Advanced Along-Track Scanning Radiometer (AATSR) with observations of tropospheric nitrogen dioxide (NO2) column densities from the Ozone Monitoring Instrument (OMI). Furthermore, simulations of the global aerosol-climate model ECHAM-HAMMOZ have been used to identify the possible processes affecting aerosol loads and their dependence on temperature over the studied region. Our results showed that the level of AOD in the southeastern US is mainly governed by anthropogenic emissions but the observed temperature dependent behaviour is most likely originating from non-anthropogenic emissions. Model simulations indicated that biogenic emissions of volatile organic compounds (BVOC) can explain the observed temperature dependence of AOD. According to the remote sensing data sets, the non-anthropogenic contribution increases AOD by approximately 0.009 ± 0.018 K−1 while the modelled BVOC emissions increase AOD by 0.022 ± 0.002 K−1. Consequently, the regional direct radiative effect (DRE) of the non-anthropogenic AOD is −0.43 ± 0.88 W/m2/K and −0.17 ± 0.35 W/m2/K for clear- and all-sky conditions, respectively. The model estimate of the regional clear-sky DRE for biogenic aerosols is also in the same range: −0.86 ± 0.06 W/m2/K. These DRE values indicate significantly larger cooling than the values reported for other forested regions. Furthermore, the model simulations showed that biogenic emissions increased the number of biogenic aerosols with radius larger than 100 nm (N100, proxy for cloud condensation nuclei) by 28 % per one degree temperature increase. For the total N100, the corresponding increase was 4 % which implies that biogenic emissions could also have a small effect on indirect radiative forcing in this region.

scholarly journals Sensitivity of biogenic volatile organic compounds to land surface parameterizations and vegetation distributions in California

2016 ◽  
Vol 9 (5) ◽  
pp. 1959-1976 ◽  
Author(s):  
Chun Zhao ◽  
Maoyi Huang ◽  
Jerome D. Fast ◽  
Larry K. Berg ◽  
Yun Qian ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Land Surface ◽  
Aerosol Formation ◽  
Biogenic Volatile Organic Compounds ◽  
Vegetation Map ◽  
Near Surface ◽  
Volatile Organic ◽  
The Impact

Abstract. Current climate models still have large uncertainties in estimating biogenic trace gases, which can significantly affect atmospheric chemistry and secondary aerosol formation that ultimately influences air quality and aerosol radiative forcing. These uncertainties result from many factors, including uncertainties in land surface processes and specification of vegetation types, both of which can affect the simulated near-surface fluxes of biogenic volatile organic compounds (BVOCs). In this study, the latest version of Model of Emissions of Gases and Aerosols from Nature (MEGAN v2.1) is coupled within the land surface scheme CLM4 (Community Land Model version 4.0) in the Weather Research and Forecasting model with chemistry (WRF-Chem). In this implementation, MEGAN v2.1 shares a consistent vegetation map with CLM4 for estimating BVOC emissions. This is unlike MEGAN v2.0 in the public version of WRF-Chem that uses a stand-alone vegetation map that differs from what is used by land surface schemes. This improved modeling framework is used to investigate the impact of two land surface schemes, CLM4 and Noah, on BVOCs and examine the sensitivity of BVOCs to vegetation distributions in California. The measurements collected during the Carbonaceous Aerosol and Radiative Effects Study (CARES) and the California Nexus of Air Quality and Climate Experiment (CalNex) conducted in June of 2010 provided an opportunity to evaluate the simulated BVOCs. Sensitivity experiments show that land surface schemes do influence the simulated BVOCs, but the impact is much smaller than that of vegetation distributions. This study indicates that more effort is needed to obtain the most appropriate and accurate land cover data sets for climate and air quality models in terms of simulating BVOCs, oxidant chemistry and, consequently, secondary organic aerosol formation.

scholarly journals Quantification of the effect of modeled lightning NO<sub>2</sub> on UV–visible air mass factors

2017 ◽  
Vol 10 (11) ◽  
pp. 4403-4419 ◽  
Author(s):  
Joshua L. Laughner ◽  
Ronald C. Cohen
Keyword(s):  
United States ◽  
A Priori ◽  
Early Summer ◽  
Lightning Flash ◽  
Eastern United States ◽  
Ozone Monitoring Instrument ◽  
Reanalysis Dataset ◽  
Near Surface ◽  
Air Mass ◽  
Convective Clouds

Abstract. Space-borne measurements of tropospheric nitrogen dioxide (NO2) columns are up to 10x more sensitive to upper tropospheric (UT) NO2 than near-surface NO2 over low-reflectivity surfaces. Here, we quantify the effect of adding simulated lightning NO2 to the a priori profiles for NO2 observations from the Ozone Monitoring Instrument (OMI) using modeled NO2 profiles from the Weather Research and Forecasting–Chemistry (WRF-Chem) model. With observed NO2 profiles from the Deep Convective Clouds and Chemistry (DC3) aircraft campaign as observational truth, we quantify the bias in the NO2 column that occurs when lightning NO2 is not accounted for in the a priori profiles. Focusing on late spring and early summer in the central and eastern United States, we find that a simulation without lightning NO2 underestimates the air mass factor (AMF) by 25 % on average for common summer OMI viewing geometry and 35 % for viewing geometries that will be encountered by geostationary satellites. Using a simulation with 500 to 665 mol NO flash−1 produces good agreement with observed NO2 profiles and reduces the bias in the AMF to  <  ±4 % for OMI viewing geometries. The bias is regionally dependent, with the strongest effects in the southeast United States (up to 80 %) and negligible effects in the central US. We also find that constraining WRF meteorology to a reanalysis dataset reduces lightning flash counts by a factor of 2 compared to an unconstrained run, most likely due to changes in the simulated water vapor profile.

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