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Central Plains region of China, represented by Henan Province, is facing serious air pollution problems. Vehicular exhaust emissions had adverse impacts on the atmospheric environment. The first comprehensive and novel vehicle emission inventory for Henan Province using vehicle kilometers traveled, localized emission factors, and activity data at city-level was developed. Furthermore, 3 km × 3 km gridded emission and temporal variations were determined by using localized information. Results show that the total emissions of sulfur dioxide (SO 2), nitrogen oxides (NO x), carbon monoxide (CO), particular matter with aerodynamic diameter < 10 μm (PM 10), aerodynamic diameter < 2.5 μm (PM 2.5), volatile organic compounds (VOCs), VOCs-evaporation and ammonia in 2015 were 9.1, 533.4, 1190.7, 23.7, 21.6, 150.8, 31.5 and 10.4 Gg, respectively, and the emission intensities of the above pollutants were 0.05, 2.7, 6.0, 0.1, 0.1, 0.8, 0.2 and 0.05 g/km, respectively. Vehicles meeting the Primary China 1, China 3 and China 4 contributed 89.1%, 82.7%, 75.3%, 75.5%, 75.5%, 68.2%, 68.4% and 82.3% for SO 2 , NO x , CO, PM 10 , PM 2.5 , VOCs, VOCs-evaporation and ammonia emissions, respectively. Zhengzhou, Zhoukou, Nanyang, Luoyang, Shangqiu and Xinyang showed relatively higher emissions and contributed more than 50% of each pollutant. The spatial distribution indicated obvious characteristics of the road network, and high-level emission was concentrated in the downtown areas. Additionally, the ozone formation potential (OFP) based on the estimated speciated VOC emissions was 569.6 Gg in Henan Province. Aliphatic and aromatic hydrocarbons were the main species of VOCs, whereas olefins contributed the largest proportion of OFP, with 42.2%. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Henan province is one of the most critical emitters of ammonia (NH 3) and is one of the most seriously air polluted regions in China. In this study, we developed a first comprehensive and novel 2015-based NH 3 emission inventory for Henan province based on investigational activity data with corrected and updated emission factors of anthropogenic and natural sources. The 3 km × 3 km gridded emissions and monthly variations were allocated by using appropriate spatial and localized temporal surrogates. The total NH 3 emission was 1031.6 Gg in 2015, of which livestock, N fertilizer application, and humans were the top three contributors, accounting for 57.3%, 28.2%, and 3.1%, respectively. The cities of Nanyang, Zhoukou, and Zhumadian with more rural and agricultural activities were demonstrated to have relatively high emissions, accounting for 12.5%, 10.1%, and 9.7% of total emissions, respectively. The regional averaged emission density was 6.3 t km−2, with higher values in eastern and northern Henan province. Obvious seasonal variability was observed, with the highest emission in July and the lowest in January associated with temperature and local farming activities. In addition, according to the emissions investigation carried out from 2006 to 2016, the largest changes occurred in non-agricultural sources. Furthermore, we quantitatively analyzed the estimated emissions with the uncertainty range of -33%-35% using the AuvToolPro tool. This emission inventory was also evaluated by comparing the magnitudes with other studies, analyzing the correlation of the observed ambient NH 3 concentration with emission density and temperature, and investigating the trend of molar ratio of (2SO 2 +NO 2)/NH 3. The emission inventory developed in this study can provide information to understand local emission characteristics, and to determine how to prioritize effective control strategies properly for policy makers. Graphical abstract Image 1 Highlights • A recent integrated and long-term high-resolution NH 3 emission inventory of Henan province was developed. • Spatiotemporal variations and quantitative uncertainty were investigated and analyzed. • Correlation analysis and molar ratio of (2SO 2 +NO 2)/NH 3 were applied to evaluate the emission inventory. • The emissions and in-situ ambient NH 3 concentration were compared with those in other studies. [ABSTRACT FROM AUTHOR]

Vehicle emission is becoming one of the most important pollution sources because of the increase in vehicle population and activity in China. A more reasonable and complete vehicle emission inventory in Zhengzhou for the year 2013 was developed in this study. This inventory is suitable for local emission factors and vehicle kilometers of travel. Estimates show that the total carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO X ), particulate matter (PM 2.5 and PM 10 ) and sulfur dioxide (SO 2 ) emissions were 291 Gg, 35 Gg, 106 Gg, 6 Gg, 7 Gg, and 3 Gg, respectively. Approximately 55% of CO and HC emissions were from light duty gasoline vehicles and normal gasoline motorcycles, whereas approximately 60% of NO X , PM 2.5 , PM 10 and SO 2 were from heavy duty diesel vehicles, heavy duty diesel trucks, and medium duty diesel trucks. The spatial distribution of emissions was allocated in grid cells based on a road network and traffic flows with a resolution of 1 km × 1 km at different road types and locations, which shows that the six aforementioned air pollutants have similar characteristics in administrative districts. Emissions are mainly concentrated on the central grid cells of each part and in good agreement with line sources. The spatial characteristics were compared at a resolution of 3 km × 3 km and in a population-based approach. The network approach yields better level estimates in this study. Meanwhile, the preliminary temporal profiles were also established for on-road mobile source. [ABSTRACT FROM AUTHOR]

Accurate and gridded VOC emission inventories are important for improving regional air quality model performance. In this study, a four-level VOC emission source categorization system was proposed. A 2010-based gridded Pearl River Delta (PRD) regional VOC emission inventory was developed with more comprehensive source coverage, latest emission factors, and updated activity data. The total anthropogenic VOC emission was estimated to be about 117.4 × 10 4 t, in which on-road mobile source shared the largest contribution, followed by industrial solvent use and industrial processes sources. Among the industrial solvent use source, furniture manufacturing and shoemaking were major VOC emission contributors. The spatial surrogates of VOC emission were updated for major VOC sources such as industrial sectors and gas stations. Subsector-based temporal characteristics were investigated and their temporal variations were characterized. The impacts of updated VOC emission estimates and spatial surrogates were evaluated by modeling O 3 concentration in the PRD region in the July and October of 2010, respectively. The results indicated that both updated emission estimates and spatial allocations can effectively reduce model bias on O 3 simulation. Further efforts should be made on the refinement of source classification, comprehensive collection of activity data, and spatial–temporal surrogates in order to reduce uncertainty in emission inventory and improve model performance. [ABSTRACT FROM AUTHOR]

During the transportation from emission sources to sampling site, volatile organic compounds (VOCs) undergo photochemical losses which have significant effects for tropospheric ozone (O 3) formation and VOCs source apportionment. In this study, based on hourly speciated VOC data from May 23, to July 8, 2019 with high O 3 concentrations, the concentration level, chemical composition, and diurnal variation of observed VOCs were studied, and the initial concentration of VOCs was obtained by combining the local emission inventory in Zhengzhou, Central China. The impact of photochemical loss on source apportionment was evaluated using the Positive Matrix Factorization/Multilinear Engine 2-Species Ratio (PMF/ME2-SR) model based on observed and initial VOCs concentration (OC-PMF and IC-PMF). Results suggest that during the observed period, the average concentration of total VOCs (TVOCs) was 23.74 ± 9.20 ppbv, and alkanes (3.92 ± 2.40 ppbv) were the predominant component. The photochemical losses of TVOCs were approximately 10.15 ± 7.13 ppbv, with an average loss rate of 29.9%. The ozone formation potential (OFP) based on the initial VOCs concentration was 2.2 times higher than that observed VOCs concentration. Alkenes contributed the most to OFP and were also the largest contributors to photochemical losses. TVOC concentrations increased by 5.0% during O 3 pollution compared to non-O 3 pollution. Seven sources of VOCs were determined, including biomass burning, liquefied petroleum gas (LPG), vehicle emission, industrial emission, solvent usage, gasoline evaporation, and biogenic emission. Compared to the results of IC-PMF, the contributions of these sources in OC-PMF were underestimated by 15.4%, 14.4%, 13.0%, 11.7%, 31.5%, 7.6%, and 4.7%, respectively. This study still exhibits certain limitations in calculation method, and further exploration can be conducted in the future. [Display omitted] • Alkenes and aromatics consumed accounted for 65.4% and 21.5% of photochemical loss, respectively. • The OFP of initial VOCs concentration was 2.2 times higher than that of measured concentration. • Sources of VOCs were identified and compared based on measured and initial VOC mixing ratios. • VOCs from solvent usage source were notably influenced by photochemical loss. [ABSTRACT FROM AUTHOR]

Abstract: Multi-year inventories of biomass burning emissions were established in the Pearl River Delta (PRD) region for the period 2003–2007 based on the collected activity data and emission factors. The results indicated that emissions of sulfur dioxide (SO2), nitrogen oxide (NOx), ammonia (NH3), methane (CH4), organic carbon (OC), non-methane volatile organic compounds (NMVOC), carbon monoxide (CO), and fine particulate matter (PM2.5) presented clear declining trends. Domestic biofuel burning was the major contributor, accounting for more than 60% of the total emissions. The preliminary temporal profiles were established with MODIS fire count information, showing that higher emissions were observed in winter (from November to March) than other seasons. The emissions were spatially allocated into grid cells with a resolution of 3 km × 3  km, using GIS-based land use data as spatial surrogates. Large amount of emissions were observed mostly in the less developed areas in the PRD region. The uncertainties in biomass burning emission estimates were quantified using Monte Carlo simulation; the results showed that there were higher uncertainties in organic carbon (OC) and elemental carbon (EC) emission estimates, ranging from −71% to 133% and −70% to 128%, and relatively lower uncertainties in SO2, NOx and CO emission estimates. The key uncertainty sources of the developed inventory included emission factors and parameters used for estimating biomass burning amounts. [Copyright &y& Elsevier]

In recent years, air pollution has been a serious problem in China, not only in the city but also in the countryside. Moreover, the statistics data of coal and solid biomass consumption for rural households are significantly underestimated, which has a negative impact on the air pollution control. In this study, Henan province, an agricultural province in China, is taken as a case to analyze the county-level emission characteristics and emission reduction potential of rural household combustion. Firstly, activity data at county-level are obtained through regression based on partial activity data from field survey in 2016, and a high-resolution emission inventory of multi-type air pollutants from rural residential combustion is established. Then, twelve abatement technologies are selected to replace coal and solid biomass used in heating and cooking. A new optimization model is established based on the rural household burden ratio to discuss the optimal emission reduction schemes at county-level under five substitution scenarios. The results show that the total emissions of SO 2 , NOx, PM 2.5 , PM 10 , CO, NH 3 and VOCs from rural residential combustion in Henan province are estimated at about 108.6, 30.9, 72.7, 113.5, 1141.9, 19.6 and 110.0 kt, respectively. The inventory results of different counties vary greatly, with PM 2.5 emissions ranging from 7.9 t to 1550.3 t. Counties with large emissions have more agricultural activities. Among the abatement technologies, air source heat pump (ASHP) and palisade structure (PS) are more suitable for promotion in rural areas. The PM 2.5 emissions in the five substitution scenarios are 99.0%, 98.8%, 99.1%, 98.6% and 98.8% lower than BAU-scenario, and S1-scenario is more conducive to rural emission reduction with considering the costs. It is suggested that the government should pay more attention to the air pollution caused by rural household combustion and improve the existing energy statistics system, especially for solid biomass. Abatement technologies suitable for heating and cooking in rural areas should be actively promoted, such as air source heat pump. Image 1 • Fuel consumption at county-level is obtained through regression models based on energy data from field surveys. • A high-resolution emission inventory of multi-type air pollutants from rural residential combustion is established. • A new optimization model is developed to obtain county-level optimal abatement schemes. • A new approach of air pollutants emission reduction is provided for rural areas. • The reduction ratio is reached 98.8% under the optimal reduction scenario. [ABSTRACT FROM AUTHOR]

Abstract: Emission trends and variations in source contributions of SO2, NO x , PM10 and VOCs in the Pearl River Delta (PRD) region from 2000 to 2009 were characterized by using a dynamic methodology, taking into account the economic development, technology penetration, and emission control. The results indicated that SO2 emissions increased rapidly during 2000–2005 but decreased significantly afterward. NO x emissions went up consistently during 2000–2009 except for a break point in 2008. PM10 emissions increased by 76% during 2000–2007 but started to decrease slightly in the following years. VOCs emissions presented continuous increase during the study period. Power plants and industrial sources were consistently the largest SO2 and PM10 emission contributors. The on-road mobile source was the largest emission contributor for VOCs and NO x emissions with decreasing contributions. The NO x contribution from power plants and industrial sources kept increasing. Worthy of mention is that the non-road mobile source is becoming an important SO2 and NO x contributor in this region. Comparisons with satellite data, ground observations and national trends indicated that emission trends developed in this study were reasonable. Implications for future air pollution control policies were discussed. [Copyright &y& Elsevier]

Abstract: Industrial sector-based VOC source profiles are reported for the Pearl River Delta (PRD) region, China, based source samples (stack emissions and fugitive emissions) analyzed from sources operating under normal conditions. The industrial sectors considered are printing (letterpress, offset and gravure printing processes), wood furniture coating, shoemaking, paint manufacturing and metal surface coating. More than 250 VOC species were detected following US EPA methods TO-14 and TO-15. The results indicated that benzene and toluene were the major species associated with letterpress printing, while ethyl acetate and isopropyl alcohol were the most abundant compounds of other two printing processes. Acetone and 2-butanone were the major species observed in the shoemaking sector. The source profile patterns were found to be similar for the paint manufacturing, wood furniture coating, and metal surface coating sectors, with aromatics being the most abundant group and oxygenated VOCs (OVOCs) as the second largest contributor in the profiles. While OVOCs were one of the most significant VOC groups detected in these five industrial sectors in the PRD region, they have not been reported in most other source profile studies. Such comparisons with other studies show that there are differences in source profiles for different regions or countries, indicating the importance of developing local source profiles. [Copyright &y& Elsevier]

Abstract: An emission pre-processing tool is generally needed to transform a bulk annual emission inventory into gridded, temporal (monthly, weekly, and hourly), and speciated emissions in order to use complex air quality models such as the Community Multi-scale Air Quality (CMAQ) model to assess control strategies, forecast air quality, and investigate pollution formation and transport processes. To support the regional air quality modeling in the Pearl River Delta (PRD), we developed an emission pre-processing system, Sparse Matrix Operator Kernel Emissions-PRD (SMOKE-PRD), based on the U.S. Environmental Protection Agency (USEPA)/SMOKE model. This paper introduces the methods and procedures for adapting the SMOKE model to the PRD regional bulk emissions. These include the compilation of the PRD local source-class clarification codes, the incorporation of the PRD local emission inventory, and the updating of spatial, temporal, and chemical speciation information. The SMOKE-PRD system was evaluated, and a case study on ozone simulation was conducted to demonstrate the applicability of the SMOKE-PRD system. Results show that the model can properly simulate temporal variations, spatial patterns, and peak values of O3 concentrations in the PRD region, suggesting the SMOKE-PRD system was successfully localized and can be used to provide model-ready emissions for regional air quality modeling in the PRD region. This work can be extended for adapting the SMOKE model to process emissions for modeling use in other regions of China. [Copyright &y& Elsevier]

Abstract: A highly resolved temporal and spatial Pearl River Delta (PRD) regional emission inventory for the year 2006 was developed with the use of best available domestic emission factors and activity data. The inventory covers major emission sources in the region and a bottom–up approach was adopted to compile the inventory for those sources where possible. The results show that the estimates for SO2, NOx, CO, PM10, PM2.5 and VOC emissions in the PRD region for the year 2006 are 711.4 kt, 891.9 kt, 3840.6 kt, 418.4 kt, 204.6 kt, and 1180.1 kt, respectively. About 91.4% of SO2 emissions were from power plant and industrial sources, and 87.2% of NOx emissions were from power plant and mobile sources. The industrial, mobile and power plant sources are major contributors to PM10 and PM2.5 emissions, accounting for 97.7% of the total PM10 and 97.2% of PM2.5 emissions, respectively. Mobile, biogenic and VOC product-related sources are responsible for 90.5% of the total VOC emissions. The emissions are spatially allocated onto grid cells with a resolution of 3 km × 3 km, showing that anthropogenic air pollutant emissions are mainly distributed over PRD central-southern city cluster areas. The preliminary temporal profiles were established for the power plant, industrial and on-road mobile sources. There is relatively low uncertainty in SO2 emission estimates with a range of −16% to +21% from power plant sources, medium to high uncertainty for the NOx emissions, and high uncertainties in the VOC, PM2.5, PM10 and CO emissions. [Copyright &y& Elsevier]