资源环境科技发展态势分析平台

Emissions of residential coal burning are an important contributor to air pollution in developing countries, but few studies have yet comprehensively characterized the physicochemical properties of individual primary particles from residential coal burning. Fine primary particles emitted from eight types of coal with low, medium, and high maturity were collected in the flaming and burn-out stages in a typical residential stove. Based on morphology and composition of individual particles, they were divided into six types: organic matter (OM), OM-S, soot-OM, S-rich, metal, and mineral particles. Low-maturity coals (e.g., lignite) dominantly emitted soot-OM particles in the flaming stage, the medium-maturity coals (e.g., medium-maturity bituminous coals) emitted abundant OM particles, and high-maturity coals (e.g., anthracite) emitted abundant OM-S particles. We found that carbonaceous particles from coal burning significantly decreased with an increase of coal maturity and that soot particles were mainly formed in the flaming stage of low-maturity coals under higher burning temperatures. We concluded that coal maturity and burning temperature both determine particulate properties in coal emissions. In addition, OM and soot particles from residential coal burning displayed extremely weak hygroscopicity, while inorganic salts within individual particles determined particle hygroscopic growth. Understanding the characteristics of particulate matter emitted from residential coal burning is helpful to trace sources of ambient particles and clarify their possible aging mechanism in air influenced by coal burning emissions. Our results suggest that air quality improvements can benefit substantially from the replacement of low-and medium-maturity coals with high-maturity coals, natural gas, or electricity in rural areas.

Plain Language Summary Raw coals have been widely used for heating and cooking in developing countries such as China, India, Mongolia, and Nepal. Due to inefficient burning and no air pollutant control devices, large amounts of air pollutants are emitted from residential coal burning to indoors and ambient air, which have additional deleterious effects on human health and global climate. In addition, recent studies suggest that residential coal burning is a main source of severe haze pollution in North China. We found that the primary organic particles are dominant aerosols in direct emission of most coal burning. However, many fine black carbon and sulfates that are normally considered as vehicular emission and secondary formation in wintertime hazes, respectively, are also found. Our study provides one database to understand what nature properties of primary aerosol particles emitted from various residential coal burning. We call that air quality improvements can benefit substantially from the replacements of low-and medium-maturity coals with high-maturity coals, natural gas, or electricity in rural areas.