Iron and Steel Industry Emissions: A Global Analysis of Trends and Drivers

The iron and steel industry (ISI) is important for socio-economic progress but emits greenhouse gases and air pollutants detrimental to climate and human health. Understanding its historical emission trends and drivers is crucial for future warming and pollution interventions. Here, we offer an exhaustive analysis of global ISI emissions over the past 60 years, forecasting up to 2050. We evaluate emissions of carbon dioxide and conventional and unconventional air pollutants, including heavy metals and polychlorinated dibenzodioxins and dibenzofurans. Based on this newly established inventory, we dissect the determinants of past emission trends and future trajectories. Results show varied trends for different pollutants. Specifically, PM2.5 emissions decreased consistently during the period 1970 to 2000, attributed to adoption of advanced production technologies. Conversely, NOx and SO2 began declining recently due to stringent controls in major contributors such as China, a trend expected to persist. Currently, end-of-pipe abatement technologies are key to PM2.5 reduction, whereas process modifications are central to CO2 mitigation. Projections suggest that by 2050, developing nations (excluding China) will contribute 52-54% of global ISI PM2.5 emissions, a rise from 29% in 2019. Long-term emission curtailment will necessitate the innovation and widespread adoption of new production and abatement technologies in emerging economies worldwide.

A Facility-Level Phaseout Strategy for China's Blast Furnaces to Address Multiple Policy Objectives

Given the urgency of addressing climate change and the declining demand for steel, it is imperative that China's iron and steel industry begin phasing out its primary production facility, the blast furnace. While there are various studies examining the decarbonization pathways for this sector and the resulting impacts, research exploring how to design decarbonization pathways that consider economic, environmental, and regional aspects equally is lacking. Moreover, it remains unclear how the individual heterogeneity of facilities affects the effectiveness of climate policies. In this study, we address the aforementioned research gaps by proposing a novel strategy that takes into account economic, carbon, water, and health factors in determining the priority for the closure of China's blast furnaces. We developed a bottom-up framework that incorporates a facility-level data set, a stock-driven dynamic material analysis, and retirement metrics with uncertain parameters to measure the multidimensional impacts of various phaseout pathways for China's blast furnaces. We have identified potential pathways that can improve environmental efficiency in multiple aspects compared with the cost-minimization pathway without impeding regional equality.

[Pollution Characteristics and Emission Factors of PCDD/Fs from Iron and Steel Industry]

The pollution level, emission characteristics, and emission factors of PCDD/Fs from a number of steel plants were investigated in a particular province of China. The results showed that the concentration of PCDD/Fs was at a low level and decreased by 1-2 orders of magnitude compared with that in 2005-2019. In detail, the concentrations of PCDD/Fs ranged from 0.003-0.557 ng·m^-3(I-TEQ), and the mean value was 0.165 ng·m^-3 for the sintering process. Moreover, the concentrations of PCDD/Fs ranged from 0.006 to 0.057 ng·m^-3, and the mean value was 0.025 ng·m^-3 for the electric furnace process. In addition, the concentration of PCDD/Fs in the iron and steel industry from 2005 to 2020 increased first and then decreased, especially after the implementation of the new emission standard and the ultra-low emission control of conventional pollutants such as smoke, showing a significant decline. The results of fingerprint analysis showed that 2,3,7,8-TCDF was the largest congener contributing to the mass concentration, and lower chlorinated PCDFs were increased. This result differed from those of previous studies in which highly chlorinated PCDFs and PCDDs dominated, indicating that the generation source of PCDD/Fs had changed. The congener and isomer profiles of PCDD/Fs in flue gas from the sintering process were similar to those in the flue gas from the electric furnace process. Additionally, showing the characteristics of the typical high-temperature thermal process, the de novo synthesis may be the dominant mechanism of formation of PCDD/Fs in the sintering process and electric furnace process. The emission factor was 0.003-0.5 μg·t^-1 (I-TEQ), and the average emission factor was (0.18±0.22) μg·t^-1 for the sintering process. The emission factor was 0.04-0.5 μg·t^-1, and the average emission factor was (0.27±0.23) μg·t^-1 for the electric furnace process. These values were far lower than those of the standard toolkit for identification and quantification of dioxin and furan emissions released by UNEP in 2013 and the emission factors in the dioxin emission inventory of China in 2004. It is suggested that the emission factors of PCDD/Fs in the iron and steel industry of China should be studied and updated.

Accidents and injuries in workers of iron and steel industry in West Bengal, India: Prevalence and associated risk factors

This study estimates the prevalence and risk factors of accidents and injuries among iron and steel industry workers. A cross-sectional study (N = 505) was conducted from November 2019 to March 2020 in the Indian Iron and Steel Company (IISCO), Burnpur, West Bengal, India. The result shows that about 28% of workers experienced accidents and injuries in the last 12 months. The most frequent injuries reported were cuts from sharp objects (37.32%), followed by fractures and dislocation (30.28%) and burns (19.01%), upper head injury (23.24%) and arm/shoulder injury (14.08%). Non-technical education (adjusted odds ratio [AOR]: 2.52), higher exposure in risky and polluted areas (AOR: 2.85), alcohol consumption (AOR: 2.47), poor occupational health and safety knowledge (AOR: 0.65) were significantly associated with work-related injuries. Occupational health and safety knowledge and usage of safety measures must be propagated and monitored to curb accidents and injuries among iron and steel industry workers in India.

[Chemical Source Profiles of PM Emitted from the Main Processes of the Iron and Steel Industry in China]

Considering the lack of numbers and updates of particulate matter (PM) source profiles, which show PM emitted from the Chinese iron and steel industry, a dilution tunnel system was used to sample PM discharged from the three main processes (sintering, puddling, and steelmaking) of an iron and steel company in Wuhan, China. Six source profiles for fine and coarse PM were established, and their characteristics were researched. The main conclusions were as follows:① For the sintering source profiles, SO₄^2-, Al, and NH₄⁺ were the dominant components, with mass fractions of 22.2%, 4.5%, and 3.5% in the PM_2.5 profile and 36.0%, 5.2%, and 2.7% in the PM₁₀ profile, respectively. Fe was abundant in puddling source profiles, the mass fractions of which reached 28.3% and 24.5% for PM_2.5 profile and PM₁₀ profile, respectively. As for steelmaking, the main components were Ca and Fe. ② For the element component features, S was enriched in the sintering source profiles. Metal elements, such as Pb and Cr, were more abundant in the puddling source profiles. ③ The coefficients of divergence for profiles were calculated. Profiles of different sizes for the same processes showed similarities, whereas the diversities between the sintering and the other two profiles were higher. 4 Compared with research in other regions, similarities and differences were found and analyzed.

[Air Pollutant Emission Inventory from Iron and Steel Industry in the Beijing-Tianjin-Hebei Region and Its Impact on PM2.5]

The iron and steel industry, which discharges a large amount of pollutants including SO₂, NO_x, and PM_2.5, is the main source of atmospheric pollution in the Beijing-Tianjin-Hebei region. Based on the bottom-up method, a high temporal and spatial resolution emission inventory of the iron and steel industry in the Beijing-Tianjin-Hebei region was developed, which took into account the multiple air pollutants released during coking, sintering, pelletizing, ironmaking, steelmaking, and the steel rolling process. As the emission inventory showed, the total emissions of SO₂, NO_x, TSP, PM₁₀, PM_2.5, CO, and VOC from the iron and steel industry in the Beijing-Tianjin-Hebei region in 2015 were 388.2, 272.3, 791.9, 531.5, 386.8, 8233.8, and 265.3 kilotons, respectively, among which, sintering and pelletizing were the two processes discharging the most pollutants (17.0%-72.0%), followed by the ironmaking process (4.6%-42.4%) and the steel rolling process (3.5%-35.7%); the iron and steel industry in Tangshan discharged the most pollutants (39.1%-63.5%) among those in all the 13 cities. The impact of the iron and steel industry on the regional PM_2.5 concentration was simulated by a two-layer nested meteorology-air quality coupling model system (WRF-CMAx) with Particulate Source Apportionment Technology (PSAT). The simulation results showed that the iron and steel industry contributed 14.0%, 15.9%, 12.3%, and 8.7% of the PM_2.5 concentrations of the Beijing-Tianjin-Hebei region in spring, summer, autumn, and winter, respectively, and that the iron and steel industry had the most significant impact on the PM_2.5 concentrations in Tangshan among all the 13 cities, with a contribution rate up to 41.2%, followed by those in Qinhuangdao, Shijiazhuang, and Handan, with contributions of 19.3%, 15.3%, and 15.1%, respectively. The iron and steel industry has an important impact on the PM_2.5 concentration of the Beijing-Tianjin-Hebei region to which the government should pay more attention, and take more effective control measures to address this problem.

[Characteristics Research on Carbonaceous Component of Particulate Matter Emitted from Iron and Steel Industry]

In order to investigate the carbonaceous characteristics of particles emitted from the iron and steel industry, an electrical low-pressure impactor (ELPI) was used to collect three sets of samples from the sintering process and one set of samples from the ironmaking process emissions of particulate matters. Organic carbon (OC) and elemental carbon (EC), which were divided into seven carbonaceous components based on the temperature of the particulate matter, were analyzed using a thermal-light reflection method. Results show that OC in sintering process particles is higher than that in ironmaking particles and accounts for 5.3%±2.3% and 7.1%±3.0% of PM₁₀ and PM_2.5, respectively, which reveals that OC tended to be enriched in fine particles. In the ironmaking process particles, OC accounted for 2.5% and 2.0% of PM₁₀ and PM_2.5, respectively. The relative proportions of the seven carbonaceous components in the four sets of samples were very similar. OC2 and OC3 accounted for the highest proportion; the EC1, EC2, and EC3 contents decreased in turn; and OC1 may be associated with boiler scale and desulfurization. In addition, the OC and EC of sintering process particles had higher correlation, and the OC/EC value of primary emission particles was 4.7±0.7, which is much higher than the value of the secondary OC estimation index in environment. Analyzing deeply on the carbonaceous characteristics in particles emitted from the iron and steel industry, which will provide essential data for source apportionment of carbonaceous aerosols in environment and will be conducive to the follow supervisory of pollution cleaning in iron and steel industry.

Hazardous waste characterization among various thermal processes in South Korea: a comparative analysis

Ministry of Environment, Republic of Korea (South Korea) is in progress of converting its current hazardous waste classification system to harmonize it with the international standard and to set-up the regulatory standards for toxic substances present in the hazardous waste. In the present work, the concentrations along with the trend of 13 heavy metals, F(-), CN(-) and 19 PAH present in the hazardous waste generated among various thermal processes (11 processes) in South Korea were analyzed along with their leaching characteristics. In all thermal processes, the median concentrations of Cu (3.58-209,000 mg/kg), Ni (BDL-1560 mg/kg), Pb (7.22-5132.25mg/kg) and Zn (83.02-31419 mg/kg) were comparatively higher than the other heavy metals. Iron & Steel thermal process showed the highest median value of the heavy metals Cd (14.76 mg/kg), Cr (166.15 mg/kg) and Hg (2.38 mg/kg). Low molecular weight PAH (BDL-37.59 mg/kg) was predominant in sludge & filter cake samples present in most of the thermal processes. Comparatively flue gas dust present in most of the thermal processing units resulted in the higher leaching of the heavy metals.