Particulate nitrate (pNO) has often been found to be the major component of fine particles in urban air-sheds in China, the United States, and Europe during winter haze episodes in recent years. However, there is a lack of knowledge regarding the experimentally determined contribution of different chemical pathways to the formation of pNO. Here, for the first time, we combine ground and tall-tower observations to quantify the chemical formation of pNO using observationally constrained model approach based on direct observations of OH and NO for the urban air-shed. We find that the gas-phase oxidation pathway (OH+NO) during the daytime is the dominant channel over the nocturnal uptake of NO during pollution episodes, with percentages of 74% in urban areas and 76% in suburban areas. This is quite different from previous studies in some regions of the US, in which the uptake of NO was concluded to account for a larger contribution in winter. These results indicate that the driving factor of nitrate pollution in Beijing and different regions of the US is different, as are the mitigation strategies for particulate nitrate.
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http://dx.doi.org/10.1021/acs.est.0c00972 | DOI Listing |
Sci Total Environ
December 2024
Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070, China; Tianjin Key Laboratory of Environment, Nutrition, and Public Health, Tianjin Medical University, Tianjin 300070, China; Center for International Collaborative Research on Environment, Nutrition and Public Health, Tianjin 300070, China; Key Laboratory of Prevention and Control of Major Diseases in the Population, Ministry of Education, Tianjin Medical University, Tianjin 300070, China.
Background: Particulate matter with diameters ≤2.5 μm (PM) is a significant air pollutant associated with hypertension and diabetes. However, the specific contributions of its components and their joint exposure with green spaces remain poorly understood, especially in developing regions.
View Article and Find Full Text PDFSci Total Environ
December 2024
Department of Public Health Sciences, University of Rochester, School of Medicine and Dentistry, Rochester, NY, USA; Institute for a Sustainable Environment, Clarkson University, Potsdam, NY, USA.
Advanced receptor models can leverage the information derived from optical and chemical variables as input by a variety of instruments at different time resolutions to extract the source specific absorption Ångström exponent (AAE) from aerosol absorption. The multilinear engine (ME-2), a Positive Matrix Factorization (PMF) solver, serves as a proficient tool for performing such analyses, thereby overcoming the constraints imposed by the assumptions in current optical source apportionment methods such as the Aethalometer approach since the use of a-priori AAE values introduces additional uncertainty into the results of optical methods. Comprehensive PM chemical speciation datasets, and aerosol absorption coefficients (b, λ) at seven wavelengths measured by an Aethalometer (AE33), were used in multi-time source apportionment (MT-PMF).
View Article and Find Full Text PDFSci Total Environ
December 2024
Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea; Institute of Health and Environment, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea. Electronic address:
This study investigates the sources, chemical composition, and vertical transport of particulate matter (PM) at Mt. Gwanak in southeastern Seoul, focusing on differences between surface and elevated altitudes during winter 2021. Using a time-of-flight aerosol chemical species mass spectrometer (ToF-ACSM), PM was measured at 632 m.
View Article and Find Full Text PDFACS EST Air
December 2024
McKelvey School of Engineering, Washington University in St. Louis, St. Louis, Missouri 63130-4899, United States.
Air quality management benefits from an in-depth understanding of the emissions associated with, and composition of, local PM concentrations. Here, we investigate the changing role of biomass burning emissions to North American PM exposure by combining multiple satellite-, ground-, and simulation-based data sets biweekly at a 0.01° × 0.
View Article and Find Full Text PDFEcotoxicol Environ Saf
December 2024
Department of Epidemiology, School of Public Health, Southern Medical University (Guangdong Provincial Key Laboratory of Tropical Disease Research), No.1023-1063, Shatai South Road, Baiyun District, Guangzhou 510515, China. Electronic address:
Background: Although the link between fine particulate matter (PM) and influenza-like illness (ILI) is well established, the effect of the chemical constituents of PM on ILI remains unclear. This study aims to explore this effect in Guangzhou, China.
Methods: Daily data on ILI cases, PM levels, and specific PM constituents (black carbon [BC], chlorine [Cl], ammonia [NH], nitrate [NO], and sulfate [SO]) in Guangzhou, China, were collected for the period of 2014-2019.
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