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Solid fuel consumption and associated emissions from residential use are highly uncertain due to a lack of reliable statistics. In this study, we estimate solid fuel consumption and emissions from the rural residential sector in China by using data collected from a new nationwide field survey. We conducted a field survey in 2010 which covered ∼17,000 rural residential households in 183 counties in China, to obtain data for solid fuel consumption and use patterns. We then developed a Generalized Additive Model (GAM) to establish the relationship between solid fuel consumption and heating degree days (HDD), income, coal production, coal price, and vegetation coverage, respectively. The GAM was used to estimate solid fuel consumption in rural households in China at the county level. We estimated that, in 2010, 179.8Tg of coal were consumed in Chinese rural households for heating and cooking, which is 62% higher than that reported in official energy statistics. We found that large quantities of rural residential coal consumption in the North China Plain were underreported in energy statistics. For instance, estimated coal consumption in rural households in Hebei (one of most polluted provinces in China) was 20.8Tg in 2010, which is twice as high as government statistics indicate. In contrast, modeled national total consumption of crop residues (used as fuels) we found to be ∼50% lower than reported data. Combining the underlying data from the survey, the GAM and emission factors from literature, we estimate emissions from China’s rural residential sector in 2010 to be: 3.3Tg PM2.5, 0.6Tg BC, 1.2Tg OC, 2.1Tg VOC, 2.3Tg SO2, 0.4Tg NOx, 43.6Tg CO and 727.2Tg CO2, contributing to 29%, 35%, 38% and 26% of national total PM2.5, BC, OC, and CO emissions respectively. This work reveals that current emission inventories in China likely underestimate emissions from coal combustion in rural residential households due to missing coal consumption in official statistics, especially for the heavily polluted North China Plain (NCP) region. Per capita income appears to be the driving factor that results in the difference between surveyed data and official data. Residents with high income prefer commercial energy and have a higher per capita fuel consumption than lower income residents. Therefore, rural residential coal combustion may contribute even more to regional air pollution than the large contributions previously identified.

The MIX inventory is developed for the years 2008 and 2010 to support the Model Inter-Comparison Study for Asia (MICS-Asia) and the Task Force on Hemispheric Transport of Air Pollution (TF HTAP) by a mosaic of up-to-date regional emission inventories. Emissions are estimated for all major anthropogenic sources in 29 countries and regions in Asia. We conducted detailed comparisons of different regional emission inventories and incorporated the best available ones for each region into the mosaic inventory at a uniform spatial and temporal resolution. Emissions are aggregated to five anthropogenic sectors: power, industry, residential, transportation, and agriculture. We estimate the total Asian emissions of 10 species in 2010 as follows: 51.3 Tg SO2, 52.1 Tg NOx, 336.6 Tg CO, 67.0 Tg NMVOC (non-methane volatile organic compounds), 28.8 Tg NH3, 31.7 Tg PM10, 22.7 Tg PM2.5, 3.5 Tg BC, 8.3 Tg OC, and 17.3 Pg CO2. Emissions from China and India dominate the emissions of Asia for most of the species. We also estimated Asian emissions in 2006 using the same methodology of MIX. The relative change rates of Asian emissions for the period of 2006–2010 are estimated as follows: −8.1 % for SO2, +19.2 % for NOx, +3.9 % for CO, +15.5 % for NMVOC, +1.7 % for NH3, −3.4 % for PM10, −1.6 % for PM2.5, +5.5 % for BC, +1.8 % for OC, and +19.9 % for CO2. Model-ready speciated NMVOC emissions for SAPRC-99 and CB05 mechanisms were developed following a profile-assignment approach. Monthly gridded emissions at a spatial resolution of 0.25° × 0.25° are developed and can be accessed from http://www.meicmodel.org/dataset-mix.

Non-methane volatile organic compounds (NMVOC) are important ozone and secondary organic aerosol precursors and play important roles in tropospheric chemistry. In this work, we estimated the total and speciated NMVOC emissions from China’s anthropogenic sources during 1990–2017 by using a bottom-up emission inventory framework, and investigated the main drivers behind the trends. We found that, anthropogenic NMVOC emissions in China have been increased continuously since 1990 due to the dramatic growth in activity rates and absence of effective control measures. We estimated that, anthropogenic NMVOC emissions in China increased from 9.76 Tg in 1990 to 28.5 Tg in 2017, mainly driven by persistent growth from the industry sector and solvent use. In the meanwhile, emissions from the residential and transportation sectors declined after 2005, partly offset the total emission increase. During 1990–2017, mass-based emissions of alkanes, alkenes, alkynes, aromatics, oxygenated VOCs (OVOC) and other species increased by 274 %, 88 %, 4 %, 387 %, 91 %, and 231 % respectively. Following the growth in total NMVOC emissions, the corresponding ozone formation potential (OFP) increased form 38.2 Tg-O3 in 1990 to 99.7 Tg-O3 in 2017. We estimated that aromatics accounted for the largest share (43 %) of total OFP, followed by alkenes (37 %) and OVOC (10 %). Growth in China's NMVOC emissions were mainly driven by the transportation sector before 2000, while industrial sector and solvent use dominated the emission growth during 2000–2010. After 2010, although emissions from the industry sector and solvent use kept growing, strict control measures on transportation and fuel transition in residential stoves have successfully slowed down the increase trend, especially after the implementation of China's clean air action since 2013. However, compared to large emission decreases of other criteria air pollutants in China (e.g., SO2, NOx, and primary PM) during 2013–2017, the relatively flat trend in NMVOC emissions and OFP revealed the absence of effective control measures, which might have contributed to the increase of ozone during the same period. Given their high contributions to emissions and OFP, tailored control measures for solvent use and industrial sources should be developed, and collaborative control strategies should be designed to mitigate both PM2.5 and ozone pollution simultaneously.

An anthropogenic emission inventory for Asia is developed for the years 2008 and 2010 to support the Model Inter-Comparison Study for Asia (MICS-Asia) and the Task Force on Hemispheric Transport of Air Pollution (TF HTAP) projects by a mosaic of up-to-date regional emission inventories. Emissions are estimated for all major anthropogenic sources in 30 countries and regions in Asia. We conducted detailed comparisons of different regional emission inventories and incorporated the best-available ones for each region into the mosaic inventory at a uniform spatial and temporal resolution. We estimate the total Asian emissions of ten species in 2010 as follows: 51.3 Tg SO2, 52.1 Tg NOx, 336.6 Tg CO, 67.0 Tg NMVOC (non-methane volatile organic compounds), 28.8 Tg NH3, 31.7 Tg PM10, 22.7 Tg PM2.5, 3.5 Tg BC, 8.3 Tg OC and 17.3 Pg CO2. Emissions from China and India dominate the emissions of Asia for most of the species. We also estimated Asian emissions in 2006 using the same methodology of MIX. The relative change rates of Asian emissions for the period of 2006–2010 are estimated as follows: −8.0 % for SO2, +19 % for NOx, +4 % for CO, +15 % for NMVOC, +2 % for NH3, −3 % for PM10, −2 % for PM2.5, +6 % for BC, +2 % for OC and +20 % for CO2. Model-ready speciated NMVOC emissions for SAPRC-99 and CB05 mechanisms were developed following a profile-assignment approach. Monthly gridded emissions at a spatial resolution of 0.25° × 0.25° are developed and can be accessed from http://www.meicmodel.org/dataset-mix.

We evaluate the recently increasing tropospheric NO2 columns in Northern China measured by the Ozone Monitoring Instrument (OMI) with an advanced power-plant NOx emission inventory and the NASA INTEX-B emission inventory, using a global chemical transport model (GEOS-Chem). In areas with newly built power plants the modeled and OMI-retrieved summertime average tropospheric NO2 columns increased by 55% and 47%, respectively, between 2005 and 2007. A monthly average increase of 1.79 Gg NOx emissions is calculated to lead to an increase of 1.0 × 10 15 molecules cm −2 in the modeled NO2 columns in the study areas. Good consistency (R 2 = 0.61, slope = 1.18, n = 14) between the increased modeled and OMI-retrieved summertime average NO2 columns is found. These results suggest that NOx emissions from large power plants in Northern China can be identified and quantified using OMI retrievals with confidence. The NASA INTEX-B emission inventory appears to underestimate the NOx emissions from the industry and transportation sectors, making it more difficult to quantify power-plant emissions when they are co-located with large cities.