A Study of Smog Issues and PM_2.5Pollutant Control Strategies in China

The increased occurrence of smoggy days in major Chinese cities is of major concern to the general public. This paper explores the major sources of PM2.5 pollutants, a key contributor to the smog in Beijing, one of China’s largest cities. Evidence indicates that the secondary PM2.5 particles formed through NOx, SOx, NH3, VOCs, etc. have a strong impact on human health. As a result, PM2.5 pollution control should not simply focus on controlling particulate emission, but should involve adopting an integrated multi-pollutant control strategy. In addition to identifying the major sources of PM2.5, this paper explores its impact on environmental and human health. Although the intention of this research is not to provide solutions for reducing PM2.5 pollution, the paper analyzes the United States’ experience with establishing PM2.5 standards and mandates. Specifically, this paper focuses on the air quality control strategies adopted in California since the 1940s and draws parallels with present-day China. The research suggests that adequate government regulation, public awareness, regional collaboration and industrial compliance are keys to successfully controlling PM2.5 pollution.

Application, Evaluation, and Process Analysis of the US EPA’s 2002 Multiple-Pollutant Air Quality Modeling Platform

A multiple-pollutant version of CMAQ v4.6 (i.e., CMAQ-MP) has been applied by the US EPA over continental US in 2002 to demonstrate the model’s capability in reproducing the long-term trends of ambient criteria and hazardous air pollutants (CAPs and HAPs, respectively) in support of regulatory analysis for air quality management. In this study, a comprehensive model performance evaluation for the full year of 2002 is performed for the first time for CMAQ-MP using the surface networks and satellite measurements. CMAQ-MP shows a comparable and improved performance for most CAPs species as compared to an older version of CMAQ that did not treat HAPs and used older versions of national emission inventories. CMAQ-MP generally gives better performance for CAPs than for HAPs. Max 8-h ozone (O3) mixing ratios are well reproduced in the O3season. The seasonal-mean performance is fairly good for fine particulate matter (PM2.5), sulfate (SO42-), and mercury (Hg) wet deposition and worse for other CAPs and HAPs species. The reasons for the model biases may be attributed to uncertainties in emissions for some species (e.g., ammonia (NH3), elemental carbon (EC), primary organic aerosol (POA), HAPs), gas/aerosol chemistry treatments (e.g., secondary or- ganic aerosol formation, meteorology (e.g., overestimate in summer precipitation), measurements (e.g., NO3-), and the use of a coarse grid resolution. CMAQ cannot well reproduce spatial and seasonal variations of column variables except for nitrogen dioxide (NO2) and the ratio of column mass of HCHO/NO2. Possible reasons include inaccurate seasonal allocation or underestimation of emissions, inaccurate BCONs at higher altitudes, lack of model treatments such as mineral dust or plume-in-grid process, and limitations and errors in satellite data retrievals. The process analysis results show that in addition to transport, gas chemistry or aerosol/emissions play the most important roles for O3 or PM2.5, respectively. For most HAPs, emissions are important sources and cloud processes are a major sink. Simulated P H2 H O2/P HNO3 and HCHO/NO2 indicate VOC-limited chemistry in major urban areas throughout the year and in other non-urban areas in winter, but NOx-limited chemistry in most areas in summer.

WATER POLLUTION AND AGRICULTURE:MULTI-POLLUTANT PERSPECTIVES

Agriculture is an important cause of multiple pollutants in water.With population growth and increasing food demand,more nutrients,plastics,pesticides,pathogens and antibiotics are expected to enter water systems in the 21st century.As a result,water science has been shifting from singlepollutant to multi-pollutant perspectives for large-scale water quality assessments.This perspective paper summarizes and discusses four main highlights related to water pollution and agriculture from the multi-pollutant perspective.These highlights reveal the spatial and temporal distribution and main sources of multiple pollutants in waters.Based on the highlights,a scientific agenda is proposed to prioritize solutions for sustainable agriculture(UN Sustainable Development Goal 2)and clean water(UN Sustainable Development Goals 6 and 14).This agenda points out that when formulating solutions for water pollution,it is essential to take into account multiple pollutants and their interactions beyond biogeochemistry.

Multiple pollutants from crop and livestock production in the Yangtze River: status and challenges

The rapid increase in the proportion of cash crops and livestock production in the Yangtze River Basin has led to commensurate increases in fertilizer and pesticide inputs. Excessive application of chemical fertilizer, organophosphorus pesticides and inappropriate disposal of agricultural waste induced water pollution and potentially threaten Agriculture Green Development(AGD). To ensure food security and the food supply capacity of the Yangtze River Basin, it is important to balance green and development, while ensuring the quality of water bodies. Multiple pollutants affect the transfer, adsorption, photolysis and degradation of each other throughout the soil-plant-water system. This paper considers the impact of multi-pollutants on the nitrogen and phosphorus cycles especially for crops, which are related to achieving food security and AGD. It presents prospective on theory, modeling and multi-pollutant control in the Yangtze River Basin for AGD that are of potential value for other developing regions.

Advances in air pollution control for key industries in China during the 13th five-year plan

Industrial development is an essential foundation of the national economy,but the industry is also the largest source of air pollution,of which power plants,iron and steel,building materials,and other industries emit large amounts of pollutants.Therefore,the Chinese government has promulgated a series of stringent emission regulations,and it is against this backdrop that research into air pollution control technologies for key industrial sectors is in full swing.In particular,during the 13th Five-Year Plan,breakthroughs have been made in pollution control technology for key industrial sectors.A multi-pollutant treatment technology system of desulfurization,denitrification,and dust collection,which applies to key industries such as power plants,steel,and building materials,has been developed.High-performance materials for the treatment of different pollutants,such as denitrification catalysts and desulfurization absorbers,were developed.At the same time,multi-pollutant synergistic removal technologies for flue gas in various industries have also become a hot research topic,with important breakthroughs in the synergistic removal of NO_(x),SO_(x),and Hg.Due to the increasingly stringent emission standards and regulations in China,there is still a need to work on the development of multi-pollutant synergistic technologies and further research and development of synergistic abatement technologies for CO_(2) to meet the requirements of ultra-low emissions in industrial sectors.