Atmospheric Emissions

Xi Lu, Jackson Salovaara, and Michael B. McElroy. 2012. “Implications of the recent reductions in natural gas prices for emissions of CO2 from the US power sector.” Environmental Science & Technology, 46, 5, Pp. 3014–3021. Publisher's VersionAbstract
CO2 emissions from the US power sector decreased by 8.76% in 2009 relative to 2008 contributing to a decrease over this period of 6.59% in overall US emissions of greenhouse gases. An econometric model, tuned to data reported for regional generation of US electricity, is used to diagnose factors responsible for the 2009 decrease. More than half of the reduction is attributed to a shift from generation of power using coal to gas driven by a recent decrease in gas prices in response to the increase in production from shale. An important result of the model is that, when the cost differential for generation using gas rather than coal falls below 2–3 cents/kWh, less efficient coal fired plants are displaced by more efficient natural gas combined cycle (NGCC) generation alternatives. Costs for generation using NGCC decreased by close to 4 cents/kWh in 2009 relative to 2008 ensuring that generation of electricity using gas was competitive with coal in 2009 in contrast to the situation in 2008 when gas prices were much higher. A modest price on carbon could contribute to additional switching from coal to gas with further savings in CO2 emissions.

Final Manuscript in DASH
This paper is from a series investigating and comparing the prospects for low- and non-carbon power generation in China and the U.S.; click here (http://news.harvard.edu/gazette/story/2012/02/model-situation/) to see coverage in the Harvard Gazette.

Jin-Tai Lin, Michael B. McElroy, and K. Folkert Boersma. 2010. “Constraint of anthropogenic NOx emissions in China from different sectors: A new methodology using separate satellite retrievals.” Atmospheric Chemistry and Physics, 10, 1, Pp. 63-78. Publisher's VersionAbstract
A new methodology is developed to constrain
Chinese anthropogenic emissions of nitrogen oxides (NOx)
from four major sectors (industry, power plants, mobile and
residential) in July 2008. It combines tropospheric NO2 column
retrievals from GOME-2 and OMI, taking advantage
of their different passing time over China (10:00 a.m. LT
(local time) versus 02:00 p.m.) and consistent retrieval algorithms.
The approach is based on the difference of NOx
columns at the overpass times of the two instruments; it thus
is less susceptible to the likely systematic errors embedded
in individual retrievals that are consistent with each other.
Also, it explicitly accounts for diurnal variations and uncertainties
of NOx emissions for individual sources. Our best
top-down estimate suggests a national budget of 6.8 TgN/yr
(5.5 TgN/yr for East China), close to the a priori bottom-up
emission estimate from the INTEX-B mission for the year of
2006. The top-down emissions are lower than the a priori
near Beijing, in the northeastern provinces and along the east
coast; yet they exceed the a priori over many inland regions.
Systematic errors in satellite retrievals are estimated to lead
to underestimation of top-down emissions by at most 17%
(most likely 10%). Effects of other factors on the top-down
estimate are typically less than 15% each, including lightning,
soil emissions, mixing in planetary boundary layer, anthropogenic
emissions of carbon monoxide and volatile organic
compounds, magnitude of a priori emissions, assumptions
on emission diurnal variations, and uncertainties in the
four sectors. The a posteriori emission budget is 5.7 TgN/yr
for East China.
Yu Zhao, Chris P Nielsen, Michael B. McElroy, Lin Zhang, and Jie Zhang. 2012. “CO emissions in China: Uncertainties and implications of improved energy efficiency and emission control.” Atmospheric Environment, 49, Pp. 103-113. Publisher's VersionAbstract
A bottom-up methodology and an improved database of emission factors combining the latest domestic field measurements are developed to estimate the emissions of anthropogenic CO from China at national and provincial levels. The CO emission factors for major economic sectors declined to varying degrees from 2005 to 2009, attributed to improved energy efficiency and/or emission control regulations. Total national CO emissions are estimated at 173 Tg for 2005 and have been relatively stable for subsequent years, despite fast growth of energy consumption and industrial production. While industry and transportation sources dominated CO emissions in developed eastern and north-central China, residential combustion played a much greater role in the less developed western provinces. The uncertainties of national Chinese CO emissions are quantified using Monte Carlo simulation at −20% to +45% (95% confidence interval). Due to poor understanding of emission factors and activity levels for combustion of solid fuels, the largest uncertainties are found for emissions from the residential sector. The trends of bottom-up emissions compare reasonably to satellite observation of CO columns and to ground observations of CO2–CO correlation slopes. The increase in the ratio for emissions of CO2 relative to CO suggests that China has successfully improved combustion efficiencies across its economy in recent years, consistent with national policies to improve energy efficiency and to control criteria air pollutants.
Jing Cao, Richard Garbaccio, and Mun S Ho. 2009. “China's 11th Five-Year Plan and the environment: Reducing SO2 emissions.” Review of Environmental Economics and Policy, 3, 2, Pp. 189-208. Publisher's VersionAbstract
China's rapid economic growth has been accompanied by a high level of environmental degradation. One of the major sources of health and ecosystem damages is sulfur dioxide (SO2). Reducing SO2 emissions is a priority of China's environmental authorities, and the 11th Five-Year Plan (2006–2010) includes the target of reducing total SO2 emissions by 10 percent from the 2005 level. Given the rapid increase in SO2 emissions that is expected to occur in absence of intervention, attaining this target will require a significant effort. This article examines the two major policy measures the government is taking to achieve the SO2 target: a shutdown of many small, inefficient power plants and the installation of desulfurization equipment on existing and new coal-fired plants. We present results from a joint U.S.–China study that we participated in, which estimated the costs and benefits of these policies. We then estimate the economy-wide impacts of the two policies using a multisector model of the Chinese economy. We find that in the aggregate, the economic benefits of the shutdown of the small power plants are large enough to offset the costs of the desulfurization equipment, even without considering the substantial environmental benefits from the reduction of emissions of SO2 and other pollutants.
Yu Lei, Qiang Zhang, Kebin He, and David G Streets. 2011. “Primary anthropogenic aerosol emission trends for China, 1990-2005.” Atmospheric Chemistry and Physics, 11, Pp. 931-954. Publisher's VersionAbstract
An inventory of anthropogenic primary aerosol
emissions in China was developed for 1990–2005 using a
technology-based approach. Taking into account changes
in the technology penetration within industry sectors and
improvements in emission controls driven by stricter emission
standards, a dynamic methodology was derived and implemented
to estimate inter-annual emission factors. Emission
factors of PM2.5 decreased by 7%–69% from 1990 to
2005 in different industry sectors of China, and emission factors
of TSP decreased by 18%–80% as well, with the measures
of controlling PM emissions implemented. As a result,
emissions of PM2.5 and TSP in 2005 were 11.0 Tg and
29.7 Tg, respectively, less than what they would have been
without the adoption of these measures. Emissions of PM2.5,
PM10 and TSP presented similar trends: they increased in
the first six years of 1990s and decreased until 2000, then
increased again in the following years. Emissions of TSP
peaked (35.5 Tg) in 1996, while the peak of PM10 (18.8 Tg)
and PM2.5 (12.7 Tg) emissions occurred in 2005. Although
various emission trends were identified across sectors, the cement
industry and biofuel combustion in the residential sector
were consistently the largest sources of PM2.5 emissions,
accounting for 53%–62% of emissions over the study period.
The non-metallic mineral product industry, including the cement,
lime and brick industries, accounted for 54%–63% of
national TSP emissions. There were no significant trends of
BC and OC emissions until 2000, but the increase after 2000
Correspondence to: K. B. He
(hekb@tsinghua.edu.cn)
brought the peaks of BC (1.51 Tg) and OC (3.19 Tg) emissions
in 2005. Although significant improvements in the estimation
of primary aerosols are presented here, there still
exist large uncertainties. More accurate and detailed activity
information and emission factors based on local tests are essential
to further improve emission estimates, this especially
being so for the brick and coke industries, as well as for coalburning
stoves and biofuel usage in the residential sector.
Clearer Skies Over China: Reconciling Air Pollution, Climate, and Economic Goals
2013. Clearer Skies Over China: Reconciling Air Pollution, Climate, and Economic Goals. Cambridge, MA: MIT Press. Publisher's VersionAbstract

A groundbreaking U.S.–Chinese inquiry into the effects of recent air pollution controls and prospective carbon taxes on China's economy and environment.

China's carbon dioxide emissions now outstrip those of other countries and its domestic air quality is severely degraded, especially in urban areas. Its sheer size and its growing, fossil-fuel-powered economy mean that China's economic and environmental policy choices will have an outsized effect on the global environmental future. Over the last decade, China has pursued policies that target both fossil fuel use and atmospheric emissions, but these efforts have been substantially overwhelmed by the country's increasing energy demands. With a billion citizens still living on less than $4,000 per year, China's energy and environmental policies must be reconciled with the goals of maintaining economic growth and raising living standards.

This book, a U.S.–Chinese collaboration of experts from Harvard and Tsinghua University, offers a groundbreaking integrated analysis of China's economy, emissions, air quality, public health, and agriculture. It first offers essential scientific context and accessible summaries of the book's policy findings; it then provides the underlying scientific and economic research. These studies suggest that China's recent sulfur controls achieved enormous environmental health benefits at unexpectedly low costs. They also indicate that judicious implementation of carbon taxes could reduce not only China's carbon emissions but also its air pollution more comprehensively than current single-pollutant policies, all at little cost to economic growth.

Yu Zhao, Chris P Nielsen, Yu Lei, Michael B. McElroy, and Jiming Hao. 2011. “Quantifying the uncertainties of a bottom-up emission inventory of anthropogenic atmospheric pollutants in China.” Atmospheric Chemistry and Physics, 11, Pp. 2295-2308. Publisher's VersionAbstract
The uncertainties of a national, bottom-up inventory
of Chinese emissions of anthropogenic SO2, NOx, and
particulate matter (PM) of different size classes and carbonaceous
species are comprehensively quantified, for the first
time, using Monte Carlo simulation. The inventory is structured
by seven dominant sectors: coal-fired electric power,
cement, iron and steel, other industry (boiler combustion),
other industry (non-combustion processes), transportation,
and residential. For each parameter related to emission factors
or activity-level calculations, the uncertainties, represented
as probability distributions, are either statistically fitted
using results of domestic field tests or, when these are
lacking, estimated based on foreign or other domestic data.
The uncertainties (i.e., 95% confidence intervals around the
central estimates) of Chinese emissions of SO2, NOx, total
PM, PM10, PM2.5, black carbon (BC), and organic carbon
(OC) in 2005 are estimated to be −14%13%, −13%37%,
−11%38%, −14%45%, −17%54%, −25%136%,
and −40%121%, respectively. Variations at activity levels
(e.g., energy consumption or industrial production) are
not the main source of emission uncertainties. Due to narrow
classification of source types, large sample sizes, and
relatively high data quality, the coal-fired power sector is estimated
to have the smallest emission uncertainties for all
species except BC and OC. Due to poorer source classifications
and a wider range of estimated emission factors,
considerable uncertainties of NOx and PM emissions from
cement production and boiler combustion in other industries
are found. The probability distributions of emission
factors for biomass burning, the largest source of BC and
OC, are fitted based on very limited domestic field measurements,
and special caution should thus be taken interpreting
these emission uncertainties. Although Monte Carlo simulation
yields narrowed estimates of uncertainties compared
to previous bottom-up emission studies, the results are not
always consistent with those derived from satellite observations.
The results thus represent an incremental research
advance; while the analysis provides current estimates of
uncertainty to researchers investigating Chinese and global
atmospheric transport and chemistry, it also identifies specific
needs in data collection and analysis to improve on
them. Strengthened quantification of emissions of the included
species and other, closely associated ones – notably
CO2, generated largely by the same processes and thus subject
to many of the same parameter uncertainties – is essential
not only for science but for the design of policies to redress
critical atmospheric environmental hazards at local, regional,
and global scales.
Xi Lu, Michael B. McElroy, Gang Wu, and Chris P Nielsen. 2012. “Accelerated reduction of SO2 emissions from the US power sector triggered by changing prices of natural gas.” Environmental Science and Technology, 46, 14, Pp. 7882-7889. Publisher's VersionAbstract
Emissions of sulfur dioxide (SO2) from the U.S. power sector decreased by 24% in 2009 relative to 2008. The Logarithmic Mean Divisia Index (LMDI) approach was applied to isolate the factors responsible for this decrease. It is concluded that 15% of the decrease can be attributed to the drop in demand for electricity triggered by the economic recession, and 28% can be attributed to switching of fuel from coal to gas responding to the decrease in prices for the latter. The largest factor in the decrease, close to 57%, resulted from an overall decline in emissions per unit of power generated from coal. This is attributed in part to selective idling of older, less efficient coal plants that generally do not incorporate technology for sulfur removal, and in part to continued investments by the power sector in removal equipment in response to the requirements limiting emissions imposed by the U.S. Environmental Protection Agency (U.S. EPA). The paper argues further that imposition of a modest tax on emissions of carbon would have ancillary benefits in terms of emissions of SO2.

Final Manuscript in DASH
This paper is from a series investigating and comparing the prospects for low- and non-carbon power generation in China and the U.S.

Yu Zhao, Michael B. McElroy, Jia Xing, Lei Duan, Chris P Nielsen, Yu Lei, and Jiming Hao. 2011. “Multiple effects and uncertainties of emission control policies in China: Public health, soil acidification, and global temperature.” Science of the Total Environment , 409, 24, Pp. 5177-5187. Publisher's VersionAbstract
Policies to control emissions of criteria pollutants in China may have conflicting impacts on public health, soil acidification, and climate. Two scenarios for 2020, a base case without anticipated control measures and a more realistic case including such controls, are evaluated to quantify the effects of the policies on emissions and resulting environmental outcomes. Large benefits to public health can be expected from the controls, attributed mainly to reduced emissions of primary PM and gaseous PM precursors, and thus lower ambient concentrations of PM2.5. Approximately 4% of all-cause mortality in the country can be avoided (95% confidence interval: 1–7%), particularly in eastern and north-central China, regions with large population densities and high levels of PM2.5. Surface ozone levels, however, are estimated to increase in parts of those regions, despite NOX reductions. This implies VOC-limited conditions. Even with significant reduction of SO2 and NOX emissions, the controls will not significantly mitigate risks of soil acidification, judged by the exceedance levels of critical load (CL). This is due to the decrease in primary PM emissions, with the consequent reduction in deposition of alkaline base cations. Compared to 2005, even larger CL exceedances are found for both scenarios in 2020, implying that PM control may negate any recovery from soil acidification due to SO2 reductions. Noting large uncertainties, current polices to control emissions of criteria pollutants in China will not reduce climate warming, since controlling SO2 emissions also reduces reflective secondary aerosols. Black carbon emission is an important source of uncertainty concerning the effects of Chinese control policies on global temperature change. Given these conflicts, greater consideration should be paid to reconciling varied environmental objectives, and emission control strategies should target not only criteria pollutants but also species such as VOCs and CO2.
Shuxiao Wang, Jiming Hao, Yongqi Lu, and Ji Li. 2007. “Local population exposure to pollutants from the major industrial sectors.” In Clearing the air: The health and economic damages of air pollution in China, edited by Mun S Ho and Chris P Nielsen. Cambridge, MA: MIT Press. Publisher's VersionAbstract
An interdisciplinary, quantitative assessment of the health and economic costs of air pollution in China, and of market-based policies to build environmental protection into economic development.
Xiannuan Lin and Karen R. Polenske. 1998. “Energy use and air-pollution impacts of China’s transportation growth.” In Energizing China: Reconciling Environmental Protection and Economic Growth, edited by Michael B. McElroy, Chris P Nielsen, Peter Lydon, and eds.. Cambridge, MA: HUCE/Harvard University Press. Publisher's VersionAbstract

As China develops its booming, fossil fuel-powered economy, is it taking lessons from the history of Western industrialization and the unforeseen environmental harms that accompanied it? Given the risks of climate change, is there an imperative, shared responsibility to help China respond to the environmental effects of its coal dependence? By linking global hazards to local air pollution concerns—from indoor stove smoke to burgeoning ground-level ozone—this volume of eighteen studies seeks integrated strategies to address simultaneously a range of harmful emissions. Counterbalancing the scientific inquiry are key chapters on China’s unique legal, institutional, political, and cultural factors in effective pollution control.

Energizing China, the stage-setting publication of an ongoing program of Harvard–China research collaboration, is distinguished by its conceptual breadth and spirit of exchange. Its contributors include twenty-two Western and seventeen Chinese scholars with a disciplinary reach that includes science, public health, engineering, economics, public policy, law, business, and China studies.

Yi-Ming Wei, Lan-Cui Liu, Ying Fan, and Gang Wu. 2007. “The impact of lifestyle on energy use and CO2 emission: An empirical analysis of China’s residents.” Energy Policy, 35, 1, Pp. 247-257. Publisher's VersionAbstract
Based on the application of a Consumer Lifestyle Approach (CLA), this paper quantifies the direct and indirect impact of lifestyle of urban and rural residents on China's energy use and the related CO2 emissions during the period 1999–2002. The results show that approximately 26 per cent of total energy consumption and 30 per cent of CO2 emission every year are a consequence of residents’ lifestyles, and the economic activities to support these demands. For urban residents the indirect impact on energy consumption is 2.44 times greater than the direct impact. Residence; home energy use; food; and education, cultural and recreation services are the most energy-intensive and carbon-emission-intensive activities. For rural residents, the direct impact on energy consumption is 1.86 times that of the indirect, and home energy use; food; education, and cultural recreation services; and personal travel are the most energy-intensive and carbon-emission-intensive activities. This paper provides quantitative evidence for energy conservation and environmental protection focused policies. China's security for energy supply is singled out as a serious issue for government policy-makers, and we suggest that government should harmonize the relationships between stakeholders to determine rational strategies.
Yuan Hu. 2007. “Implementation of voluntary agreements for energy efficiency in China.” Energy Policy, 35, 11, Pp. 5541-5548. Publisher's VersionAbstract
Low-energy efficiency and environmental pollution have long been taken as key problems of Chinese industry, although a number of command-and-control and economic instruments have been adopted in the last few decades. In this paper, policy and legislation development for voluntary agreements were summarized. The voluntary agreements pilot project in two iron and steel companies in Shandong Province as well as other cases were analyzed. In order to identify the existing problems in Chinese cases, comparison was made between China and industrialized countries in the practices of energy efficiency voluntary agreements. Based on the analysis, detained recommendations, including the use of supporting policies for voluntary agreements, were raised. It is expected that voluntary agreements could play a more important role in energy efficiency improvement of Chinese industry.
Yanxia Zhang, Haikun Wang, Sai Liang, Ming Xu, Weidong Liu, Shalang Li, Rongrong Zhang, Chris P Nielsen, and Jun Bi. 2014. “Temporal and spatial variations in consumption-based carbon dioxide emissions in China.” Renewable & Sustainable Energy Reviews, 40, Pp. 60-68. Publisher's VersionAbstract

China’s CO2 emissions have sharply increased in recent years with soaring economic development and urbanization. Consumption-based accounting of CO2 emissions could provide new insights for allocating regional mitigation responsibility and curbing the emissions. A multi-regional input–output model is used to study the trends and disparities of consumption-based emissions from Chinese provinces during the period 2002–2007. Results show that China’s consumption-based CO2 emissions grew from 3549 Mt in 2002 to 5403 Mt in 2007 with an annual average growth rate of 8.8%. The annual growth rate in the richer eastern region was over 10% because of a rapid increase in capital investment and the growth of urban consumption. Consumption-based CO2 emissions embodied in interprovincial trades contributed only 10% (351 Mt) to the national total of such emissions in 2002, but 16% (864 Mt) in 2007. Given low per capita emissions currently, China’s consumption-based emissions have much room to grow because of further development of urbanization and stimulation of domestic demand. The government should pay greater attention to controlling CO2 emissions from a consumption-based perspective.

Chris P Nielsen and Mun S Ho. 2007. “Air pollution and health damages in China: An introduction and review.” In Clearing the air: The health and economic damages of air pollution in China, edited by Chris P Nielsen and Mun S Ho. Cambridge, MA: MIT Press. Publisher's VersionAbstract
An interdisciplinary, quantitative assessment of the health and economic costs of air pollution in China, and of market-based policies to build environmental protection into economic development.

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