Impact Of Biogenic Emissions Research Articles

The Impact of Meteorology and Emissions on Surface Ozone in Shandong Province, China, during Summer 2014-2019.

China has been experiencing severe ozone pollution problems in recent years. While a number of studies have focused on the ozone-pollution-prone regions such as the North China Plain, Yangtze River Delta, and Pearl River Delta regions, few studies have investigated the mechanisms modulating the interannual variability of ozone concentrations in Shandong Province, where a large population is located and is often subject to ozone pollution. By utilizing both the reanalysis dataset and regional numerical model (WRF-CMAQ), we delve into the potential governing mechanisms of ozone pollution in Shandong Province—especially over the major port city of Qingdao—during summer 2014–2019. During this period, ozone pollution in Qingdao exceeded the tier II standard of the Chinese National Ambient Air Quality (GB 3095-2012) for 75 days. From the perspective of meteorology, the high-pressure ridge over Baikal Lake and to its northeast, which leads to a relatively low humidity and sufficient sunlight, is the most critical weather system inducing high-ozone events in Qingdao. In terms of emissions, biogenic emissions contribute to ozone enhancement close to 10 ppb in the west and north of Shandong Province. Numerical experiments show that the local impact of biogenic emissions on ozone production in Shandong Province is relatively small, whereas biogenic emissions on the southern flank of Shandong Province enhance ozone production and further transport northeastward, resulting in an increase in ozone concentrations over Shandong Province. For the port city of Qingdao, ship emissions increase ozone concentrations when sea breezes (easterlies) prevail over Qingdao, with the 95th percentile reaching 8.7 ppb. The findings in this study have important implications for future ozone pollution in Shandong Province, as well as the northern and coastal areas in China.

Impacts of biogenic emissions from urban landscapes on summer ozone and secondary organic aerosol formation in megacities

The impact of biogenic emissions on ozone and secondary organic aerosol (SOA) has been widely acknowledged; nevertheless, biogenic emissions emitted from urban landscapes have been largely ignored. We find that including urban isoprene in megacities like Beijing improves not only the modeled isoprene concentrations but also its diurnal cycle. Specifically, the mean bias of the simulated isoprene concentrations is reduced from 87% to 39% by adding urban isoprene emissions while keeping the diurnal cycle the same as that in non-urban or rural areas. Further adjusting the diurnal cycle of isoprene emissions to the urban profile steers the original early morning peak of the isoprene concentration to a double quasi-peak, i.e., bell shape, consistent with observations. The efficiency of ozone generation caused by isoprene emissions in urban Beijing is found to be twice as large as those in rural areas, indicative of vital roles of urban BVOC emissions in modulating the ozone formation. Our study also shows that in the future along with NOx emission reduction, isoprene emissions from urban landscapes will become more important for the formation of ozone in urban area, and their contributions may exceed that of isoprene caused by transport from rural areas. Finally, the impact of biogenic emissions on SOA is examined, revealing that biogenic induced SOA accounts for 16% of the total SOA in urban Beijing. The effect of isoprene on SOA (iSOA) is modulated through two pathways associated with the abundance of NOx emissions, and the effect can be amplified in future when NOx emissions are reduced. The findings of our study are not limited to Beijing but also apply to other megacities or densely populated regions, suggesting an urgent need to construct an accurate emission inventory for urban landscapes and evaluate their impact on ozone and SOA in air quality planning and management.

The impact of biogenic emissions on ozone formation in the Yangtze River Delta region based on MEGANv3.1

Biogenic volatile organic compounds (BVOCs) play an important role in atmospheric chemistry due to their large quantities and high reactivity. In this study, the impacts of BVOC emissions on ozone formation were investigated based on MEGANv3.1 in the Yangtze River Delta (YRD) region, which has increasingly suffered from ozone pollution in recent years. The sensitivities of BVOC emissions to different drought stress configurations and the quality of emission factors were evaluated. Furthermore, BVOC contribution to ozone formation was simulated by integrated meteorology and air quality model system and the impacts of different BVOC emission scenarios on ozone concentration were discussed. Annual BVOC emissions estimated with the default drought stress configuration (i.e., base case) was 6.8 × 105 tons. The drought stress algorithm implemented in MEGANv3.1 could suppress BVOC emissions by 58% and this algorithm was sensitive to the choice of wilting point values. The BVOC contribution to the average of daily maximum 8 h ozone concentration without drought stress effect in July 2016 was 104% higher than that in the base scenario when the drought stress effect is activated. Using an alternative set of wilting point led to BVOC contribution being 48% higher than that in the base scenario. High contributions of BVOCs to simulated ozone concentration were found in northern Zhejiang, especially in Hangzhou and its surrounding areas.

Impact of biogenic emissions on early summer ozone and fine particulate matter exposure in the Seoul Metropolitan Area of Korea

Understanding how ozone (O3) and fine particulate matter (PM) formation respond to the precursor concentrations in the presence of biogenic emissions (BEs) and thereby changes in health effects can be a key step to design effective air quality management plans. This is particularly true in the Seoul Metropolitan Area (SMA), where future significant controls of anthropogenic sources of O3 and PM2.5 precursors are expected. In this paper, we investigate the effects of BEs on O3 and fine PM (PM2.5) concentrations during a strong photochemical air pollution season in the SMA in Korea. O3 and PM2.5 levels are modeled with and without BEs in June 2008. Further, we perform the health impact assessments (HIA) of O3 and PM2.5 concentration changes due to BEs to seek useful implications for air quality management by utilizing the adjusted exposure concentration fields for O3 and PM2.5 with an observation fusing (OBF) method. With BEs, daily maximum 8-h average O3 (maximum 8-h O3) and secondary organic aerosol (SOA) concentrations in the SMA increase by 17 and 474%, respectively. These increments are associated with significant consumption of photochemical oxidants (Ox), such as a ~ 60% reduction in OH∙ radicals. The reduction in Ox, conversely, lowers the production of secondary inorganic aerosols (SIOAs) by 2.7%. Adjusted O3 and PM2.5 exposure metrics and the subsequent HIA reveal that large mean increments of O3, about 8.43 ppb, due to BEs are responsible for approximately 62 all-cause premature mortalities in the SMA in June. However, mean increment of PM2.5 due to BEs is approximately 0.3 μg m−3 and results in negligible impacts on the all-cause mortality. Significant correlations of O3 and mortality rates (MR) with the VOC/NOx ratios across the SMA suggest that controlling volatile organic compounds (VOCs) from anthropogenic sources can be a priority to reduce O3 levels and population health risks in the SMA. Specifically, linear relationships of log [O3] and log [MR] to log [VOC/NOx] ensure that a 10% decrease in the VOC/NOx ratios through the VOC abatements would lead to a 1.5% decrease in the O3 levels and a 4.3% decrease in the MR on average across the SMA.

Estimation of biogenic VOC emissions and its impact on ozone formation over the Yangtze River Delta region, China

Biogenic volatile organic compounds (BVOCs) play an important role in the formation of tropospheric ozone. In the present work, biogenic emissions over the Yangtze River Delta (YRD) region for year 2014 were developed based on the interpretation of remote sensing image and MODIS data using the Model of Emissions of Gases and Aerosols from Nature (MEGAN). Impact of BVOCs emissions over the YRD region on ozone formation was investigated based on the Weather Research and Forecasting (WRF)-Community Multi-scale Air Quality (CMAQ) modeling system for July 2014. Two parallel scenarios-with and without BVOCs emissions-were developed to evaluate the influence of BVOCs emission on ozone formation. Biogenic emissions were estimated to be 18.86 × 105 ton yr−1 over the YRD region for year 2014, with higher emissions in the southern YRD region than the northern region, and higher emissions in summer than other seasons. Model evaluation showed fairly good model performances, with the index of agreement (IOA) of meteorological parameters and ozone concentrations of 0.80–0.95 and 0.76–0.91, respectively. Ozone concentrations mainly concentrated in the northwest, which is the downwind of the YRD region in summer. Impact of biogenic emissions on ozone formation exhibited a strong spatial pattern: high contributions were observed in the middle YRD region, including Bengbu, Tongling, Hefei, Huzhou, Nanjing and Zhenjiang, with the maximum hourly ozone contribution of 18.43–36.18μg/m3 during July 18 to 23. Ozone concentrations in rural areas would be more likely to be influenced by BVOCs emissions than urban areas.

An assessment of enhanced biogenic emissions influence on ozone formation in central Alberta, Canada

Emissions from biogenic sources are the primary source of isoprene and monoterpene that contribute to the formation of ozone and secondary organic aerosol (SOA). In this study, we used a regional air quality model to examine the sensitivity of simulated ozone to biogenic emission estimates. We created a new regional database of plant functional type (PFT) and land use and land cover (LULC) based on two satellite data products, the Alberta Vegetation Inventory (AVI) and Earth Observation for Sustainable Development of forests (EOSD).The Model for Emissions for Gases and Aerosols from Nature (MEGAN) biogenic emissions model was used with the new PFT data as well as the default Moderate Resolution Imaging Spectroradiometer (MODIS) PFT to generate biogenic emissions in Alberta. The comparison revealed that the new LULC increased isoprene (ISOP) emissions by 30–40 %, decreased monoterpene emissions by 7–8 %, and increased NO emissions by 65–90 % associated with the new regional plant functional type fractional (PFTf) database. This study further investigated the impact of using Alberta-specific biogenic emission on ambient ozone concentration through the Community Multi-scale Air Quality (CMAQ) modeling system against the default MEGAN emissions. In addition, the result from using the new LULC on the predicted fourth highest daily maximum 8-h ozone concentration were examined, which showed a substantial reduction (6 ppb) in ozone in the urbanized capital region area when compared to the default the LULC with less ozone changes in the rural areas. This is likely due to ozone formation in the urban areas being more sensitive to changes in volatile organic compound (VOC) emissions than the rural areas. As CMAQ tended to overestimate the observed ozone peaks in the urban areas, the use of the enhanced LULC resulted in improved model performance compared to the default LULC database. This study results will be primarily used to understand impact of biogenic emission into air on ambient air quality and secondary to provide strategic advice on air quality management plan and initiatives regarding air issues (e.g., ozone) in the region. Results also can be implied to the relationship between climate change-induced increases in biogenic VOC emissions and ozone concentrations.

Impact of biogenic emissions on ozone and fine particles over Europe: Comparing effects of temperature increase and a potential anthropogenic NOx emissions abatement strategy

The impact of biogenic emissions on ozone and PM2.5 levels over Europe is assessed using CMAQ. Biogenic emissions are predicted to increase Max8hrO3 mixing ratios by 5.7% and to decrease PM2.5 concentrations by 1.9%, increasing PM2.5_OC by 13.6% and decreasing PM2.5_SO4, PM2.5_NO3 and PM2.5_NH4 by 5.6%, 3.7% and 5.6%, respectively, on average over Europe due to their interactions with anthropogenic emissions. A suite of perturbations in temperature is imposed individually on the base case conditions in order to determine the sensitivities to air temperature changes. Temperature increases of 1, 2 or 3° K suggest an average increase in Max8hrO3 mixing ratios of 0.9%, 1.8% or 2.9%, respectively, and an average decrease in daily average PM2.5 concentrations of 2.5%, 4.2% and 5.8%, respectively, increasing PM2.5_OC and decreasing PM2.5_SO4, PM2.5_NO3 and PM2.5_NH4 component concentrations on average over Europe. In order to examine if abatement measures for anthropogenic emissions could offset ozone increases in higher temperatures and their effect on PM2.5 concentrations, a simulation with a domain wide reduction in anthropogenic NOx emissions of 10% is performed. This is estimated to reduce Max8hrO3 mixing ratios by 1.3% on average over Europe. However, NOx reduction is estimated to increase Max8hrO3 in VOCs limited areas. The reduction in anthropogenic NOx emissions is predicted to reduce PM2.5 concentrations by 1.0% enhancing the reduction simulated, here, with temperature increase but further modifying PM2.5 component concentrations.

Impact of biogenic emissions on air quality over Europe and North America

This study aims to compare the relative impact of biogenic emissions on ozone (O3) and particulate matter (PM) concentrations between North America (NA) and Europe. The simulations are conducted with the Polyphemus air quality modeling system over July and August 2006. Prior to the sensitivity study on the impact of biogenic emissions on air quality, the modeling results are compared to observational data, as well as to the concentrations obtained by other modeling teams of the Air Quality Model Evaluation International Initiative (AQMEII) study. Over Europe, three distinct emission inventories are used. Model performance is satisfactory for O3, PM10 and PM2.5 with all inventories with respect to the criteria described in the literature. Furthermore, the rmse and errors are lower than the average rmse and errors of the AQMEII simulations. Over North America, the model performance satisfies the criteria described in the literature for O3, PM10 and PM2.5. Polyphemus results are within the range of the AQMEII model results. Although the rmse and errors are higher than the average of the AQMEII simulations for O3, they are lower for PM10 and PM2.5. The impact of biogenic and anthropogenic emissions on O3 and PM concentrations is studied by removing alternatively biogenic and anthropogenic emissions in distinct simulations. Because biogenic species interact strongly with NOx, the impact of biogenic emissions on O3 concentrations varies with variations of the Volatile Organic Compound (VOC)/NOx ratio. This impact is larger over NA than Europe. O3 decreases by 10–11% on average over Europe and 20% over NA. Locally, the relative impact is also higher in NA (60% maximum) than in Europe (35% maximum). O3 decreases near large urban centers where biogenic emissions are large (e.g. Los Angeles, Chicago, Houston in NA, Milan in Europe). Most of secondary organic aerosols (SOA) formed at the continental scale over Europe and NA are biogenic aerosols. Eliminating biogenic emissions reduces SOA by 72–88% over Europe and by 90% over NA. However, biogenic SOA are not only impacted by biogenic but also by anthropogenic emissions: eliminating all anthropogenic emissions affects oxidant levels and the absorbing carbon mass, reducing the formation of SOA by 15–16% over Europe and by about 10% over NA; Furthermore, locally, the reduction may be as large as 50%, especially over large urban centers in Europe and NA.

Impacts of biogenic emissions on photochemical ozone production in Houston, Texas

A regional chemical transport model (CTM) has been employed to assess the influence of biogenic emissions on ozone (O3) formation in Houston, Texas during an eight‐day episode of 24–31 August 2000 in association with the Texas Air Quality Study (TexAQS) 2000. The effects of isoprene and monoterpene emissions on O3 photochemistry in this region were investigated. Isoprene emissions played an important role in O3 formation when the O3 plume occurred in the afternoon over the urban Houston area. When the isoprene emissions were decreased or increased by 50%, the O3 concentration was decreased or increased by 5–25 ppb over the urban Houston area, respectively, but the change in the O3 concentration was less than 5–10 ppb over the industrial Ship Channel. Additional sensitivity studies showed that the surface O3 change resulted primarily from local isoprene emissions, although transport of isoprene from the north of the urban Houston area was found to be nonnegligible in the isoprene budget on several days. The contribution of monoterpene emissions to O3 formation was insignificant due to low emission rate and relatively slow reaction rate.

Model study of the impact of biogenic emission on regional ozone and the effectiveness of emission reduction scenarios over eastern China

Model study of the impact of biogenic emission on regional ozone and the effectiveness of emission reduction scenarios over eastern China

Model study of the impact of biogenic emission on regional ozone and the effectiveness of emission reduction scenarios over eastern China

The impact of biogenic emission on regional ozone and emission control scenarios has been numerically studied through a series of sensitivity model simulations. A typical episode with elevated ozone over eastern China from 12 to 16 August 2001 was investigated by using a tropospheric chemistry and transport model (TCTM), driven by a non-hydrostatic mesoscale model MM5. The meteorological conditions during this period were characterized by high-pressure systems associated with low wind speeds, high temperatures and clear skies. Afternoon ozone concentrations exceeding 80 parts per billion (ppb) occurred over broad areas of eastern China. There is a generally good agreement between simulation and observation, indicating that the TCTM is able to represent major physical and chemical processes of tropospheric ozone and well reproduce the diurnal and day-to-day variability associated with synoptic conditions. The sensitivity analysis reveals a significant influence of biogenic hydrocarbons on regional ozone. Ozone levels are apparently enhanced by biogenic emission over large areas of eastern China. The largest increase up to 30 ppb in daytime average concentration is found in portions of the middle reaches of the Yangtze River, Yangtze Delta and northeast China. However, the response of ozone to biogenic emission varies spatially, showing more sensitivity in polluted areas than that in clean rural areas. The regimes limited by nitrogen oxides (NOx) and volatile organic carbon (VOC) in eastern China are further investigated with respect to biogenic emission. Ozone shows a clear tendency to shift from VOC limitation to NOx limitation as it moves from urban and industrial areas to rural areas. Most of the rural areas in southern China tend to be NOx limited, whereas most of the northern parts of China appear to be VOC limited. By considering biogenic emission, ozone tends to become more NOx limited and less VOC limited, both in extent and intensity, over eastern china. Furthermore, some regions have completely shifted from being VOC limited to being NOx limited.

Impact of biogenic emissions on ozone formation in the Mediterranean area – a BEMA modelling study

The aim of this modelling study is to understand and quantify the influence of biogenic volatile organic compound (BVOC) emissions on the formation of tropospheric ozone in the Burriana area (north of Valencia) on the east coast of Spain. The mesoscale modelling system used consists of the meteorology/transport module TVM and the chemical reaction mechanism RACM. The results of the model simulations are validated and compared with the data collected during the biogenic emissions in the mediterranean area (BEMA) field campaign that took place in June 1997. Anthropogenic and biogenic emission inventories have been constructed with an hourly resolution. Averaged (over the land area and over 24 h) emission fluxes for AVOC, anthropogenic NO x , BVOC and biogenic NO x are given by 16.0, 9.9, 6.2, and 0.7 kg km −2 day −1, respectively. The impact of biogenic emissions is investigated on peak ozone values by performing simulations with and without biogenic emissions, while keeping anthropogenic emissions constant. The impact on ozone formation is also studied in combination with some anthropogenic emissions reduction strategies, i.e. when anthropogenic VOC emissions and/or NO x emissions are reduced. A factor separation technique is applied to isolate the impact due to biogenic emissions from the overall impact due to biogenic and anthropogenic emissions together. The results indicate that the maximum impact of biogenic emissions on ozone formation represents at the most 10 ppb, while maximum ozone values are of the order of 100 ppb. At different locations the maximum impact is reached at different times of the day depending on the arrival time of the sea breeze. It is also shown that this impact does not coincide in time with the maximum simulated ozone concentrations that are reached over the day. By performing different emission reduction scenarios, BVOC impacts are found to be sensitive mainly to NO x , and not to AVOC. Finally, it is shown that amongst the various BVOCs emitted by the citrus plantations in Burriana, the carbonyl species contribute the most to ozone formation.

A modeling study of the effect of biogenic hydrocarbons on rural ozone formation

Abstract A simple box model was developed to assess the impact of biogenic emissions on rural air quality. High emission fluxes and most‐favorable meteorological conditions were used to estimate an upper limit to the ozone‐forming potential of biogenic hydrocarbons from a hypothetical forest in central North Carolina. The results suggest that natural hydrocarbons are not a significant source of ozone in rural areas.