Inside China’s green transition

Cement manufacturing contributes significantly to global carbon emissions, mainly due to the chemical process involved in producing clinker. ✅ Statement I: Cement industry emissions are estimated to be around 5-8% of global CO₂ emissions, making it a major source of greenhouse gases. ✅Statement II: Silica-bearing clay is indeed mixed with limestone during cement making to provide essential minerals like silicon, aluminum, and iron needed for the final product. ✅Statement III: During clinker production, limestone (calcium carbonate) is heated and converted into lime (calcium oxide), releasing CO₂ in the process. This calcination is the main source of carbon emissions in cement manufacturing. Both Statements II and III are correct, but only Statement III directly explains the source of carbon emissions mentioned in Statement I.

Fuel Cell Electric Vehicles (FCEVs) powered by hydrogen generate electricity by combining hydrogen (H₂) with oxygen (O₂) in a fuel cell. This process produces electricity, heat, and the only exhaust emission is water vapour (H₂O), making hydrogen fuel cells zero-emission.

* Green hydrogen is any hydrogen that is produced from renewable energy. * Statement 1 is correct: Green hydrogen can be used as a direct fuel for internal combustion engines, replacing conventional fuels like gasoline or diesel. * Statement 2 is correct: Green hydrogen can be blended with natural gas and used as a fuel for various applications like heating, power generation, and industrial processes. * Statement 3 is correct: Green hydrogen can be used in hydrogen fuel cells to power electric vehicles, providing a clean and efficient alternative to traditional fossil fuel-powered vehicles. Therefore, all three statements regarding the uses of green hydrogen are correct.

The Common Carbon Metric (CCM) is a protocol developed by the United Nations Environment Program's Sustainable Buildings & Climate Initiative (UNEP-SBCI) for measuring energy use and reporting greenhouse gas (GHG) emissions from building operations. Its purpose is to support GHG emissions reductions through accurate measurement of energy efficiency. It is a universal method of measuring a building's carbon footprint and allows emissions from buildings around the world to be consistently assessed and compared. Therefore, it is used for assessing the carbon footprint of building operations around the world.

1. Copper slag is a by-product generated during the extraction and refining of copper. It can be used as a partial replacement for sand in concrete production, thus reducing the demand for natural resources. This reduces the environmental impact associated with sand mining. 2. Cold mix asphalt technology involves producing asphalt mixtures at lower temperatures compared to traditional hot mix asphalt. This results in reduced energy consumption during production and lower emissions of greenhouse gases. Cold mix asphalt also allows for the use of recycled materials, further enhancing its environmental sustainability. 3. Geotextiles are synthetic materials used in road construction for various purposes such as soil stabilisation, drainage, and erosion control. They can help in reducing the need for excessive excavation and use of natural resources like stone and gravel, thereby minimizing environmental impact. 4. Hot mix asphalt technology involves producing asphalt mixtures at high temperatures. While it provides excellent performance properties for roads, it typically requires higher energy consumption during production compared to cold mix asphalt technology. 5. Portland cement is a key ingredient in concrete production. While it is widely used in construction, its production process is energy-intensive and emits significant amounts of carbon dioxide, contributing to greenhouse gas emissions. Therefore, the correct answer is A. 1, 2, and 3 only.

Statement 1 is Incorrect: While some carbon monoxide might be produced during the smelting process, it's unlikely to be in lethal quantities with proper emission controls. Statement 2 is Correct: Copper slag, a byproduct of the smelting process, can contain heavy metals like lead, arsenic, and cadmium. Rainwater or acidic runoff can leach these metals from the slag, contaminating soil and water resources. Statement 3 is Correct: Sulphur dioxide (SO2) is a major pollutant released during copper smelting, primarily from the burning of sulfur-containing fossil fuels used in the process. SO2 emissions contribute to acid rain and air pollution.

Direct Air Capture (DAC) is a technology that removes CO₂ directly from the air for storage or use in various industries. ✅ Statement I is correct:
* DAC captures CO₂ for carbon sequestration, reducing greenhouse gases. ✅ Statement II is correct:
* Captured CO₂ can be used to make plastics and in food processing. ✅ Statement III is correct:
* DAC provides carbon to make synthetic low-carbon aviation fuels by combining with hydrogen. So, the correct answer is: C

Statement 1 is correct: Fly ash finds various applications in construction, including brick manufacturing. Its pozzolanic properties improve the strength and durability of bricks.
Statement 2 is correct: Fly ash can partially replace Portland cement in concrete mixes. It reacts with the hydration byproducts of cement to form additional cementitious materials, leading to benefits like improved workability, reduced heat of hydration, and enhanced concrete performance.
Statement 3 is incorrect: Fly ash primarily consists of silicon dioxide (SiO2), aluminum oxide (Al2O3), and calcium oxide (CaO). However, it may also contain trace amounts of heavy metals like arsenic, mercury, and chromium.

A circular economy focuses on minimizing waste, reusing resources, and improving efficiency, all of which help lower greenhouse gas emissions and conserve raw materials. ✅ Statement I: Correct By reducing waste and energy use, the circular economy helps cut greenhouse gas emissions. ✅ Statement II: Correct It reduces the need for raw materials through reuse, recycling, and product life extension. ✅ Statement III: Correct It also lowers production waste using efficient and sustainable design and processes.

In a steel furnace, coke reacts with iron ore , releasing iron and generating CO and CO2 gases. Due to the use of coal , pollutants such as SOx and NOx are released, therefore all are correct options.