Expert Insight: Revised Ambient Air Quality Standards Highlight the Importance of Ammonia Slip and Condensable Particulate Matter Control

As China prepares to implement the revised Ambient Air Quality Standards on March 1, 2026, the industrial emission control sector is entering a new phase of deeper and more comprehensive air pollution management. In this edition of MirShine Environmental’s Policy Interpretation Series, Professor Guiqin Zhang, core expert of the MirShine Ecological Research Institute and Master’s Supervisor at Shandong Jianzhu University, shares her professional insights on the implications of the revised standards and the future development direction of ammonia-based flue gas desulfurization technology.

With decades of experience in atmospheric environmental science and air pollution control research, Professor Zhang has conducted extensive studies on coal-fired flue gas treatment technologies and environmental policy development. Her analysis provides valuable guidance for industrial enterprises seeking long-term compliance under increasingly stringent environmental regulations.

Stricter PM2.5 Standards Signal a New Stage of Air Pollution Control

One of the most significant changes introduced in the revised Ambient Air Quality Standards is the tightening of the annual PM2.5 concentration limit from 35 μg/m³ to 25 μg/m³.

According to Professor Zhang, this adjustment represents far more than a numerical revision. It reflects China’s transition from conventional pollution control toward a deeper and more refined stage of air quality management.

“Every tightening of environmental standards requires a corresponding advancement in industrial emission control technologies,” Professor Zhang explained. “For industries such as coal chemical processing, thermal power generation, and coke production, merely meeting current emission limits is no longer sufficient. Enterprises must adopt forward-looking technologies that can adapt to future regulatory developments.”

As governments continue to pursue cleaner air and lower particulate concentrations, industrial facilities are expected to face increasing scrutiny regarding both primary and secondary pollutant emissions.

Hidden Challenges: Ammonia Slip and Condensable Particulate Matter

While conventional flue gas treatment technologies have made significant progress in controlling sulfur dioxide (SO₂), nitrogen oxides (NOₓ), and filterable particulate matter, Professor Zhang emphasized that the industry must pay greater attention to two often-overlooked pollutants: ammonia slip and condensable particulate matter (CPM).

These pollutants are increasingly recognized as critical contributors to secondary PM2.5 formation and may become key factors influencing future environmental compliance.

In SCR denitrification systems and conventional wet desulfurization processes, unreacted ammonia may escape with the flue gas. Once released into the atmosphere, ammonia can react with sulfur dioxide, nitrogen oxides, and other acidic compounds to form secondary aerosols such as ammonium sulfate and ammonium nitrate. These fine particles are important contributors to ambient PM2.5 pollution.

Condensable particulate matter presents an additional challenge. Unlike conventional particulate matter, CPM exists primarily in gaseous form within the flue gas stream and is often difficult to capture using standard dust collection equipment. After being discharged through the stack, these gaseous compounds cool and condense in the atmosphere, forming fine solid or liquid particles that contribute directly to PM2.5 concentrations.

Professor Zhang noted that even facilities demonstrating excellent performance in conventional particulate emissions may still struggle to achieve meaningful PM2.5 reduction if ammonia slip and CPM emissions are not properly controlled.

She further highlighted that regulatory authorities have already introduced testing methodologies and emission standards targeting these pollutants. Environmental supervision is gradually expanding from traditional pollutant control toward comprehensive pollutant management.

For industrial enterprises, proactive investment in secondary pollutant control technologies is becoming both a compliance requirement and a competitive advantage.

The Unique Advantages of Ammonia-Based Desulfurization

Building upon her policy analysis, Professor Zhang examined the role of ammonia-based desulfurization technology under the evolving regulatory framework.

Unlike traditional desulfurization processes, ammonia-based flue gas desulfurization utilizes ammonia as the absorbent while offering the potential for simultaneous control of sulfur dioxide, ammonia slip, and condensable particulate matter through optimized system design.

Through patented equipment structures and carefully engineered process parameters, ammonia-based desulfurization systems can achieve multi-pollutant control without requiring extensive additional end-of-pipe treatment facilities.

Operational data from projects in coal chemical, thermal power, coking, and advanced materials industries demonstrate excellent environmental performance. In these applications, ammonia slip concentrations have consistently remained well below the regulatory limit of 3 mg/m³, while condensable particulate matter emissions have also achieved industry-leading levels.

Professor Zhang emphasized that the technology offers significant economic advantages in addition to its environmental benefits.

First, ammonia-based desulfurization operates without generating desulfurization wastewater, eliminating the capital investment and operating costs associated with wastewater treatment and zero-liquid-discharge systems.

Second, the process converts sulfur dioxide into ammonium sulfate, a valuable fertilizer product that can be sold commercially, enabling the recycling of sulfur resources and creating both environmental and economic returns.

Industry Trends: Future Competitiveness Will Depend on Comprehensive Pollutant Control

Looking ahead, Professor Zhang believes that the tightening of PM2.5 standards will fundamentally reshape the competitive landscape of industrial emission control.

“The future of flue gas treatment will no longer be defined simply by whether a company can meet emission standards,” she explained. “The real challenge will be achieving compliance with lower environmental impacts and greater economic efficiency.”

The ability to effectively control ammonia slip, condensable particulate matter, sulfur dioxide, and other emerging pollutants will become a key indicator of technological advancement.

Recent monitoring data from ammonia-based desulfurization projects further support this conclusion.

Measured concentrations of SO₂, NOₓ, and particulate matter consistently met ultra-low emission requirements.

Particulate matter concentrations obtained through dilution tunnel sampling, including both filterable particulate matter (FPM) and condensable particulate matter (CPM), remained below 5 mg/m³. Results were only 0.2–0.5 mg/m³ higher than those obtained through conventional gravimetric and beta-ray measurement methods, indicating extremely low CPM levels.

At the same time, ammonia concentrations remained below 2.0 mg/m³, significantly lower than the regulatory limit of 3.0 mg/m³, demonstrating the effectiveness of precise ammonia injection control strategies.

MirShine Continues Advancing Clean Air Technologies

As a leading provider of ammonia-based desulfurization solutions, MirShine Environmental has developed proprietary technologies focused on the coordinated control of ammonia slip and condensable particulate matter.

Through years of engineering practice across multiple industries, MirShine has accumulated extensive experience in helping clients achieve ultra-low emissions while improving operational efficiency and environmental performance.

The company’s technological roadmap aligns closely with future regulatory trends and the growing demand for comprehensive pollutant management.

Moving forward, MirShine will continue to invest in technological innovation and practical engineering solutions, supporting industries worldwide in achieving cleaner emissions, higher resource efficiency, and sustainable development goals.