Analyzing the spatio-temporal variation of the CO emissions from district heating systems with "Coal-to-Gas" transition: Evidence from GTWR model and satellite data in China.

Understanding the spatio-temporal heterogeneous effects of socioeconomic and meteorological factors on CO emissions from combinations of different district heating systems with "Coal-to-Gas" transition can contribute to the development of future low-carbon energy systems that are efficient and effective. This work downscales city-level CO emissions to a 3 × 3 km gridded level in northern China during 2012 to 2018. By employing the Geographically and Temporally Weighted Regression (GTWR) model, nighttime light (NTL) data are adopted as a proxy of the level of urbanization, and the Temperature-Humidity-Wind (THW) Index is used as a proxy of meteorological factors in the downscaling model.

TROPOMI NO in the United States: A Detailed Look at the Annual Averages, Weekly Cycles, Effects of Temperature, and Correlation With Surface NO Concentrations.

Observing the spatial heterogeneities of NO air pollution is an important first step in quantifying NO emissions and exposures. This study investigates the capabilities of the Tropospheric Monitoring Instrument (TROPOMI) in observing the spatial and temporal patterns of NO pollution in the continental United States. The unprecedented sensitivity of the sensor can differentiate the fine-scale spatial heterogeneities in urban areas, such as emissions related to airport/shipping operations and high traffic, and the relatively small emission sources in rural areas, such as power plants and mining operations.

Natural gas shortages during the "coal-to-gas" transition in China have caused a large redistribution of air pollution in winter 2017.

The Chinese "coal-to-gas" and "coal-to-electricity" strategies aim at reducing dispersed coal consumption and related air pollution by promoting the use of clean and low-carbon fuels in northern China. Here, we show that on top of meteorological influences, the effective emission mitigation measures achieved an average decrease of fine particulate matter (PM) concentrations of ∼14% in Beijing and surrounding areas (the "2+26" pilot cities) in winter 2017 compared to the same period of 2016, where the dispersed coal control measures contributed ∼60% of the total PM reductions. However, the localized air quality improvement was accompanied by a contemporaneous ∼15% upsurge of PM concentrations over large areas in southern China.

Disentangling the Impact of the COVID-19 Lockdowns on Urban NO From Natural Variability.

TROPOMI satellite data show substantial drops in nitrogen dioxide (NO) during COVID-19 physical distancing. To attribute NO changes to NO emissions changes over short timescales, one must account for meteorology. We find that meteorological patterns were especially favorable for low NO in much of the United States in spring 2020, complicating comparisons with spring 2019.

Enhanced Capabilities of TROPOMI NO: Estimating NO from North American Cities and Power Plants.

The TROPOspheric Monitoring Instrument (TROPOMI) is used to derive top-down NO emissions for two large power plants and three megacities in North America. We first re-process the vertical column NO with an improved air mass factor to correct for a known systematic low bias in the operational retrieval near urban centers. For the two power plants, top-down NO emissions agree to within 10% of the emissions reported by the power plants.

Exploiting OMI NO satellite observations to infer fossil-fuel CO emissions from U.S. megacities.

Fossil-fuel CO emissions and their trends in eight U.S. megacities during 2006-2017 are inferred by combining satellite-derived NO emissions with bottom-up city-specific NO-to-CO emission ratios.

Evaluation of China's Environmental Pressures Based on Satellite NO Observation and the Extended STIRPAT Model.

China's rapid urbanization and industrialization have affected the spatiotemporal patterns of nitrogen dioxide (NO) pollution, which has led to greater environmental pressures. In order to mitigate the environmental pressures caused by NO pollution, it is of vital importance to investigate the influencing factors. We first obtained data for NO pollution at the city level using satellite observation techniques and analyzed its spatial distribution.

Analysis of the origins of black carbon and carbon monoxide transported to Beijing, Tianjin, and Hebei in China.

A novel back-trajectory approach was adopted to determine the origins of black carbon (BC) and carbon monoxide (CO) transported to Beijing, Tianjin and Hebei. Results showed that the transport efficiency was controlled mainly by mid-latitude westerlies in winter, the South Asian monsoon in summer and prevailing westerly and northwesterly winds in spring and autumn. Hebei was identified as the most important source region of both BC (respectively accounting for 55% and 49%) and CO (39% and 38%) transported to Beijing and Tianjin.

Author Correction: India Is Overtaking China as the World's Largest Emitter of Anthropogenic Sulfur Dioxide.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Impacts of transportation sector emissions on future U.S. air quality in a changing climate. Part II: Air quality projections and the interplay between emissions and climate change.

In Part II of this work we present the results of the downscaled offline Weather Research and Forecasting/Community Multiscale Air Quality (WRF/CMAQ) model, included in the "Technology Driver Model" (TDM) approach to future U.S. air quality projections (2046-2050) compared to a current-year period (2001-2005), and the interplay between future emission and climate changes.

Impacts of transportation sector emissions on future U.S. air quality in a changing climate. Part I: Projected emissions, simulation design, and model evaluation.

Emissions from the transportation sector are rapidly changing worldwide; however, the interplay of such emission changes in the face of climate change are not as well understood. This two-part study examines the impact of projected emissions from the U.S.

India Is Overtaking China as the World's Largest Emitter of Anthropogenic Sulfur Dioxide.

Severe haze is a major public health concern in China and India. Both countries rely heavily on coal for energy, and sulfur dioxide (SO) emitted from coal-fired power plants and industry is a major pollutant contributing to their air quality problems. Timely, accurate information on SO sources is a required input to air quality models for pollution prediction and mitigation.

Historical releases of mercury to air, land, and water from coal combustion.

Coal combustion is one of the largest contemporary sources of anthropogenic mercury (Hg). It releases geologically sequestered Hg to the atmosphere, and fly ash can contaminate terrestrial and aquatic systems. We estimate that coal combustion has released a cumulative total of 38.

Total Mercury Released to the Environment by Human Activities.

We estimate that a cumulative total of 1540 (1060-2800) Gg (gigagrams, 10 grams or thousand tonnes) of mercury (Hg) have been released by human activities up to 2010, 73% of which was released after 1850. Of this liberated Hg, 470 Gg were emitted directly into the atmosphere, and 74% of the air emissions were elemental Hg. Cumulatively, about 1070 Gg were released to land and water bodies.

Transboundary health impacts of transported global air pollution and international trade.

Millions of people die every year from diseases caused by exposure to outdoor air pollution. Some studies have estimated premature mortality related to local sources of air pollution, but local air quality can also be affected by atmospheric transport of pollution from distant sources. International trade is contributing to the globalization of emission and pollution as a result of the production of goods (and their associated emissions) in one region for consumption in another region.

Satellite NO retrievals suggest China has exceeded its NO reduction goals from the twelfth Five-Year Plan.

China's twelfth Five-Year Plan included pollution control measures with a goal of reducing national emissions of nitrogen oxides (NO) by 10% by 2015 compared with 2010. Multiple linear regression analysis was used on 11-year time series of all nitrogen dioxide (NO) pixels from the Ozone Monitoring Instrument (OMI) over 18 NO hotspots in China. The regression analysis accounted for variations in meteorology, pixel resolution, seasonal effects, weekday variability and year-to-year variability.

Impacts of the Minamata convention on mercury emissions and global deposition from coal-fired power generation in Asia.

We explore implications of the United Nations Minamata Convention on Mercury for emissions from Asian coal-fired power generation, and resulting changes to deposition worldwide by 2050. We use engineering analysis, document analysis, and interviews to construct plausible technology scenarios consistent with the Convention. We translate these scenarios into emissions projections for 2050, and use the GEOS-Chem model to calculate global mercury deposition.

Light absorption properties and radiative effects of primary organic aerosol emissions.

Organic aerosols (OAs) in the atmosphere affect Earth's energy budget by not only scattering but also absorbing solar radiation due to the presence of the so-called "brown carbon" (BrC) component. However, the absorptivities of OAs are not represented or are poorly represented in current climate and chemical transport models. In this study, we provide a method to constrain the BrC absorptivity at the emission inventory level using recent laboratory and field observations.

Effectiveness of mitigation measures in reducing future primary particulate matter emissions from on-road vehicle exhaust.

This work evaluates the effectiveness of on-road primary particulate matter emission reductions that can be achieved by long-term vehicle scrappage and retrofit measures on regional and global levels. Scenario analysis shows that scrappage can provide significant emission reductions as soon as the measures begin, whereas retrofit provides greater emission reductions in later years, when more advanced technologies become available in most regions. Reductions are compared with a baseline that already accounts for implementation of clean vehicle standards.

Global chemical composition of ambient fine particulate matter for exposure assessment.

Epidemiologic and health impact studies are inhibited by the paucity of global, long-term measurements of the chemical composition of fine particulate matter. We inferred PM2.5 chemical composition at 0.

Historical Mercury releases from commercial products: global environmental implications.

The intentional use of mercury (Hg) in products and processes ("commercial Hg") has contributed a large and previously unquantified anthropogenic source of Hg to the global environment over the industrial era, with major implications for Hg accumulation in environmental reservoirs. We present a global inventory of commercial Hg uses and releases to the atmosphere, water, soil, and landfills from 1850 to 2010. Previous inventories of anthropogenic Hg releases have focused almost exclusively on atmospheric emissions from "byproduct" sectors (e.

Mercury stable isotope signatures of world coal deposits and historical coal combustion emissions.

Mercury (Hg) emissions from coal combustion contribute approximately half of anthropogenic Hg emissions to the atmosphere. With the implementation of the first legally binding UNEP treaty aimed at reducing anthropogenic Hg emissions, the identification and traceability of Hg emissions from different countries/regions are critically important. Here, we present a comprehensive world coal Hg stable isotope database including 108 new coal samples from major coal-producing deposits in South Africa, China, Europe, India, Indonesia, Mongolia, former USSR, and the U.

Response of fish tissue mercury in a freshwater lake to local, regional, and global changes in mercury emissions.

A suite of mechanistic atmospheric and mercury (Hg) cycling and bioaccumulation models is applied to simulate atmospheric Hg deposition and Hg concentrations in the water column and in fish in a Hg-impaired freshwater lake located in the northeastern United States that receives its Hg loading primarily through deposition. Two future-year scenarios evaluate the long-term response of fish tissue Hg concentrations to reductions in local and nationwide coal-fired electric-generating utility and other Hg emissions and an increase or decrease in global (non-US) Hg emissions. Results indicate that fish tissue Hg concentrations in this ecosystem could require approximately 3 yr to 8 yr to begin to respond to declines in US emissions and deposition with a fish Hg reduction proportional to deposition reduction requiring over 50 yr.

China's international trade and air pollution in the United States.

China is the world's largest emitter of anthropogenic air pollutants, and measurable amounts of Chinese pollution are transported via the atmosphere to other countries, including the United States. However, a large fraction of Chinese emissions is due to manufacture of goods for foreign consumption. Here, we analyze the impacts of trade-related Chinese air pollutant emissions on the global atmospheric environment, linking an economic-emission analysis and atmospheric chemical transport modeling.