Warming influenced by the ratio of black carbon to sulphate and the black-carbon source

Ramana, M. V.; Ramanathan, V.; Feng, Yan; Yoon, Soon‐Chang; Kim, S. W.; Carmichael, G. R.; Schauer, James J.

doi:10.1038/ngeo918

Cited by 246 publications

(201 citation statements)

References 23 publications

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“…This dramatic surface dimming of 7-10% is attributed (6,34) to increased aerosol emissions in the region; total BC+SO 2 emissions and reduction in total surface radiation are correlated with R 2 = 0.44. Recent research indicates that the net radiative forcing of OC (once thought to be pure scattering) is in reality close to zero (31), and that the relative abundance of BC and sulfates is the main determinant of overall aerosol radiative forcing (35). We therefore include BC and SO 2 emissions (as the main precursor for sulfate aerosols) in our model, and omit OC.…”

Section: Black Carbonmentioning

confidence: 99%

Recent climate and air pollution impacts on Indian agriculture

Burney

Ramanathan

2014

Proc. Natl. Acad. Sci. U.S.A.

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267

152

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Recent research on the agricultural impacts of climate change has primarily focused on the roles of temperature and precipitation. These studies show that India has already been negatively affected by recent climate trends. However, anthropogenic climate changes are a result of both global emissions of long-lived greenhouse gases (LLGHGs) and other short-lived climate pollutants (SLCPs). Two potent SLCPs, tropospheric ozone and black carbon, have direct effects on crop yields beyond their indirect effects through climate; emissions of black carbon and ozone precursors have risen dramatically in India over the past three decades. Here, to our knowledge for the first time, we present results of the combined effects of climate change and the direct effects of SLCPs on wheat and rice yields in India from 1980 to 2010. Our statistical model suggests that, averaged over India, yields in 2010 were up to 36% lower for wheat than they otherwise would have been, absent climate and pollutant emissions trends, with some densely populated states experiencing 50% relative yield losses. [Our point estimates for rice (−20%) are similarly large, but not statistically significant.] Upper-bound estimates suggest that an overwhelming fraction (90%) of these losses is due to the direct effects of SLCPs. Gains from addressing regional air pollution could thus counter expected future yield losses resulting from direct climate change effects of LLGHGs.climate impacts | ozone | aerosols | agriculture | India

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Section: Black Carbonmentioning

confidence: 99%

Recent climate and air pollution impacts on Indian agriculture

Burney

Ramanathan

2014

Proc. Natl. Acad. Sci. U.S.A.

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267

152

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“…Total carbon (i.e., the sum of OC and EC or carbonaceous aerosol) contribution to the mean China urban aerosol mass ranges from 20% to 50% in both fine and coarse fractions [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. OC and EC have long been studied to investigate their effects on the regional climate, air quality, and visibility in China [16][17][18]. However, these indicators are of concern owing to their possible adverse effects on human health, as several studies have supported a positive correlation between exposure to OC or EC and the exacerbation of cardiopulmonary diseases or the increase of daily mortality [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Organic and Elemental Carbon in PM2.5 and PM0.25 in Indoor and Outdoor Environments of a Middle School: Secondary Formation of Organic Carbon and Sources Identification

Guinot

Shen

et al. 2015

Atmosphere

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Secondary organic carbon (SOC) formation and its effects on human health require better understanding in Chinese megacities characterized by a severe particulate OPEN ACCESSAtmosphere 2015, 6 362 pollution and robust economic reform. This study investigated organic carbon (OC) and elemental carbon (EC) in PM2.5 and PM0.25 collected 8-20 March 2012. Samples were collected inside and outside a classroom in a middle school at Xi'an. On average, OC and EC accounted for 20%-30% of the particulate matter (PM) mass concentration. By applying the EC-tracer method, SOC's contribution to OC in both PM size fractions was demonstrated. The observed changes in SOC:OC ratios can be attributed to variations in the primary production processes, the photochemical reactions, the intensity of free radicals, and the meteorological conditions. Total carbon (TC) source apportionment by formula derivation showed that coal combustion, motor vehicle exhaust, and secondary formation were the major sources of carbonaceous aerosol. Coal combustion appeared to be the largest contributor to TC (50%), followed by motor vehicle exhaust (25%) and SOC (18%) in both size fractions.

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“…4). In the northeast Pacific rim, outflows transported from areas around Beijing tended to show a higher ratio of black carbon to sulfate than those from other parts of China, exerting a strong positive influence on the net warming (Lim et al, 2012;Ramana et al, 2010).…”

Section: Ssa In Relation To Major Aerosol Compositionmentioning

confidence: 99%

Absorption and scattering properties of organic carbon versus sulfate dominant aerosols at Gosan climate observatory in Northeast Asia

et al. 2014

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Abstract. Carbonaceous and soluble ionic species of PM 1.0 and PM 10 were measured along with the absorption and scattering properties and aerosol number size distributions at Gosan Climate Observatory (GCO) from January to September 2008. The daily averaged equivalent black carbon (EBC) measured as aerosol absorption exhibited two types of spectral dependence with a distinct maximum (peak) at either 370 nm or 880 nm, by which two subsets were extracted and classified into the respective groups (370 and 880 nm). The 370 nm group was distinguished by high organic carbon (OC) concentrations relative to elemental carbon (EC) and sulfate, but sulfate was predominant for the 880 nm group. The PM 1.0 OC of the 370 nm group was mainly composed of refractory and pyrolized components that correlated well with PM 1.0 EC1, referred to as char EC, which suggests biofuel and biomass combustion as the source of these OC fractions, particularly during winter. The scanning electron microscope (SEM) images and the number size distributions implied that aerosols of the 370 nm group were externally mixed upon transport in fast-moving air masses that passed through the Beijing area in about one day. In contrast, the aerosols of the 880 nm group were characterized by high sulfate concentrations, and seemed to be internally mixed during slow transport over the Yellow Sea region over approximately 2 to 4 days. The absorption and scattering coefficients of the 880 nm group were noticeably higher compared to those of the 370 nm group. The average absorption ångström exponent (AAE) was estimated to be 1.29 and 1.0 for the 370 and 880 nm groups, respectively, in the range 370-950 nm. These results demonstrated that the optical properties of aerosols were intimately linked to chemical composition and mixing state, characteristics determined both by source and atmospheric aging processes. In OC dominant aerosols, absorption was enhanced in the UV region, which was possibly due to refractory and pyrolized OC compounds. Under sulfate dominant conditions, the sulfate coating on BC particles likely contributed to the absorption of the longer visible light. Consequently, single scattering albedo (SSA) was higher for the 880 nm group than for the 370 nm group, emphasizing that the relative abundances of absorbing and scattering constituents are also important in estimating the climate effect of aerosols.

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Warming influenced by the ratio of black carbon to sulphate and the black-carbon source

Cited by 246 publications

References 23 publications

Recent climate and air pollution impacts on Indian agriculture

Recent climate and air pollution impacts on Indian agriculture

Characteristics of Organic and Elemental Carbon in PM2.5 and PM0.25 in Indoor and Outdoor Environments of a Middle School: Secondary Formation of Organic Carbon and Sources Identification

Absorption and scattering properties of organic carbon versus sulfate dominant aerosols at Gosan climate observatory in Northeast Asia

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