Abstract Nitrated phenols are among the major constituents of brown carbon and affect both climates and ecosystems. However, emissions from biomass burning, which comprise one of the most important primary sources of atmospheric nitrated phenols, are not well understood. In this study, the concentrations and proportions of 10 nitrated phenols, including nitrophenols, nitrocatechols, nitrosalicylic acids, and dinitrophenol, in fine particles from biomass smoke were determined under three different burning conditions (flaming, weakly flaming, and smoldering) with five common types of biomass (leaves, branches, corncob, corn stalk, and wheat straw). The total abundances of fine nitrated phenols produced by biomass burning ranged from 2.0 to 99.5 μg m−3. The compositions of nitrated phenols varied with biomass types and burning conditions. 4-nitrocatechol and methyl nitrocatechols were generally most abundant, accounting for up to 88–95% of total nitrated phenols in flaming burning condition. The emission ratios of nitrated phenols to PM2.5 increased with the completeness of combustion and ranged from 7 to 45 ppmm and from 239 to 1081 ppmm for smoldering and flaming burning, respectively. The ratios of fine nitrated phenols to organic matter in biomass burning aerosols were comparable to or lower than those in ambient aerosols affected by biomass burning, indicating that secondary formation contributed to ambient levels of fine nitrated phenols. The emission factors of fine nitrated phenols from flaming biomass burning were estimated based on the measured mass fractions and the PM2.5 emission factors from literature and were approximately 0.75–11.1 mg kg−1. According to calculations based on corn and wheat production in 31 Chinese provinces in 2013, the total estimated emission of fine nitrated phenols from the burning of corncobs, corn stalks, and wheat straw was 670 t. This work highlights the apparent emission of methyl nitrocatechols from biomass burning and provides basic data for modeling studies.
Summertime HONO concentrations were synchronously measured at two (agricultural and nonagricultural) sites in the North China Plain (NCP). Daytime HONO (1.4 ± 0.6 ppbv) and HONO/NO2 ((12 ± 8)%) over the agricultural field after fertilization were found to be remarkably higher than those before fertilization, implying strong HONO emission from the fertilized fields. Synchronous enhancements of HONO and O3 after fertilization at both sites suggested that the emitted HONO accelerated the local and the regional O3 pollution. HONO budget analysis further revealed that its emission was significantly enhanced after fertilization. Soil HONO emission flux and its uncertainty were estimated and discussed. The estimated emission flux exhibited a distinct diurnal variation with a noontime maximum. The net OH production rate from HONO photolysis greatly exceeded that from O3 photolysis over the agricultural field, and their maximum ratio of 4.7 was obtained after fertilization. We provide field evidence that fertilized fields in the NCP act as a strong HONO source, which accelerates daytime photochemistry, leading to an increase of regional photo-oxidants such as O3. Considering the severe O3 pollution in the summer NCP and that the large area of the agricultural field is regularly treated with high fertilization amount in this region, HONO emission should be taken into account in the regional air quality deterioration.
Abstract. Filter samples of fine particulate matters were collected at four sites in northern China (urban, rural, and mountain) in summer and winter, and the contents of nine nitrated phenols were quantified in the laboratory with the use of ultra-high-performance liquid chromatography coupled with mass spectrometry. During the sampling periods, the concentrations of particulate nitrated phenols exhibited distinct temporal and spatial variation. On average, the total concentration of particulate nitrated phenols in urban Jinan in the wintertime reached 48.4 ng m−3, and those in the summertime were 9.8, 5.7, 5.9, and 2.5 ng m−3 in urban Jinan, rural Yucheng and Wangdu, and Mt. Tai, respectively. The elevated concentrations of nitrated phenols in wintertime and in urban areas demonstrate the apparent influences of anthropogenic sources. The positive matrix factorization receptor model was then applied to determine the origins of particulate nitrated phenols in northern China. The five major source factors were traffic, coal combustion, biomass burning, secondary formation, and aged coal combustion plume. Among them, coal combustion played a vital role, especially at the urban site in the wintertime, with a contribution of around 55 %. In the summertime, the observed nitrated phenols were highly influenced by aged coal combustion plumes at all of the sampling sites. Meanwhile, in remote areas, contributions from secondary formation were significant. Further correlation analysis indicates that nitrosalicylic acids were produced mostly from secondary formation that was dominated by NO2 nitration.
Abstract. Samples of fine particulate matters were collected at four sites in North China (urban, rural, and mountain) in summer and winter, and the contents of nine nitrated phenols were quantified in the laboratory with the use of ultra-high-performance liquid chromatography coupled with mass spectrometry. During the sampling periods, the concentrations of particulate nitrated phenols exhibited distinct temporal and spatial variation. On average, the total concentrations of particulate nitrated phenols in urban Ji'nan in the wintertime reached 48.4 ng m−3, and those in the summertime were 9.8, 5.7, 5.9, and 2.5 ng m−3 in urban Ji'nan, rural Yucheng and Wangdu, and Mt. Tai, respectively. The elevated concentrations of nitrated phenols in wintertime and in urban areas demonstrate the apparent influences from anthropogenic sources. The positive matrix factorization receptor model was then applied to determine the origins of particulate nitrated phenols in North China. The five major source factors were traffic, coal combustion, biomass burning, secondary formation, and aged coal combustion plume. Among them, coal combustion played a vital role, especially at the urban site in the wintertime, with a contribution of around 55 %. In the summertime, the observed nitrated phenols were highly influenced by aged coal combustion plumes at all of the sampling sites. Meanwhile, in remote areas, contributions from secondary formations were significant. Further correlation analysis indicates that nitrosalicylic acids were produced mostly from secondary formations that were dominated by NO2 nitration.
Nitrate (NO3-) is a major component of atmospheric fine particles. Recent studies have reported the increasing trend of NO3- in contrast to the ongoing control of nitrogen oxides (NOx) in eastern China. Here, we elucidate the effects of the reduction in sulfur dioxide (SO2) on the enhancement of NO3- formation based on field measurements at the summit of Mt. Tai (1534 m a.s.l) and detailed modelling analyses. From 2007 to 2018, the measured springtime concentrations of various primary pollutants and fine sulfate (SO42-) dropped sharply (-16.4% – -89.7%), while fine NO3- concentration increased by 22.8%. The elevated NO3- cannot be explained by the changes in meteorological conditions or other related parameters, but was largely attributed to the large reduction in SO42- (-73.4%). Results from a multi-phase chemical box model indicate that the reduced SO42- decreased the aerosol acidity and thus prompted the partitioning of HNO3 into the aerosol phase. WRF-Chem model analyses suggest that such a negative effect is a regional phenomenon throughout the planetary boundary layer over eastern China. This study provides new insights into the worsening situation of NO3- aerosol pollution and has important implications for haze pollution control in China.
The pilot policy of carbon emissions trading rights covers six heavy pollution industries in the manufacturing industry and has achieved considerable emission reductions. Based on enterprise behavior, this study analyzes the impact of the carbon emissions trading rights pilot policy on the productivity of manufacturing enterprises. In addition, we examine whether the pilot policy can aid in the transformation and upgrading of China’s manufacturing industry. Furthermore, we examine the influence of carbon emissions trading rights on manufacturing enterprises of different sizes and with different property rights. The results show that the trading rights have not produced a “Porter effect” on the productivity of manufacturing enterprises in China or in subsamples based on the nature of enterprise ownership. The impact of the carbon trading rights on the productivity of state-owned manufacturing enterprises in the pilot provinces is based on the compliance cost hypothesis. Therefore, the pilot policy has yet to achieve coordinated economic, social, and environmental development. Lastly, we put forward several policy suggestions on the coordinated development of a carbon trading policy and manufacturing enterprises from the perspective of the government, enterprises, and society.
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