The evolution and importance of aerosol monitoring

Air pollution has long been a critical environmental and public health issue, particularly in regions with high industrial activity.

While discussions on air quality have often focused on particulate matter (PM), sulfur oxides (SOx), nitrogen oxides (NOx), and carbon monoxide (CO), there is another, often less spoken about, but equally significant factor - aerosols.

These microscopic particles contribute to air pollution and have far-reaching implications on climate, and public health.

Seb Evans spoke to Viswanath Venkataraman, Business Development Manager at Metrohm, to explore the evolution of air monitoring technologies, the challenges of compliance with stricter emission regulations, and the often-overlooked importance of aerosol monitoring in ambient air quality assessments.

The evolution of air monitoring technology

Air monitoring has evolved significantly over the years.

Initially, efforts centered around dust monitoring, primarily focusing on PM2.5 and PM10 levels.

These particulate matter measurements provided insights into air quality by assessing the concentration of airborne particles within a specific size range.

Over time, technological advancements allowed for the monitoring of SOx, NOx, and CO - key pollutants associated with industrial and non-industrial emissions.

These gases were easier to measure due to the availability of direct spectroscopic methods, which enabled cost-effective and reliable detection.

Aerosol monitoring was largely ignored due to the complexity of measuring it.

‘Aerosol monitoring has traditionally been overlooked because measuring is far more complex than detecting gases like SOx and NOx,’ said Viswanath.

‘But now, we have the technology to analyze these components and more, in real-time giving us a much clearer picture of air pollution.’

The role of aerosol monitoring in air quality assessment

Unlike gaseous pollutants that are directly measurable, aerosols require a long-term collection followed by a conversion into a liquid state for accurate assessment.

This complexity has historically limited the development of real-time aerosol monitoring technologies.

Metrohm specializes in this overlooked area.

Unlike traditional monitoring systems that capture hourly or daily snapshots – providing data over time, their technology collects data every hour, providing a more comprehensive analysis of aerosol behaviour.

This offers researchers information on pollution levels and their dispersion over time.

‘Real-time aerosol monitoring allows us to detect pollution spikes as they happen,’ Viswanath explained.

‘This is crucial for industries and regulators looking to implement timely interventions.’

Challenges in compliance with stricter emission regulations

As governments worldwide implement stricter environmental regulations, industries face increasing challenges in ensuring compliance.

While many countries have established monitoring stations at critical positions providing localized measurements, these are often insufficient to map the full extent of pollution spread across wider areas.

High costs and technical maintenance requirements make it difficult for many countries to deploy comprehensive air monitoring networks.

Metrohm addresses these challenges by integrating remote connectivity into the system for collection data and also monitor the operational status of the system.

The system can be stationed at different locations for extended periods, offering a dynamic perspective on aerosol and pollution patterns.

‘Many existing monitoring networks are static, meaning they don’t capture how pollution moves,’ said Viswanath.

‘Our mobile stations provide a more dynamic approach.’

Why aerosols have been overlooked

Though everyone knew the importance of aerosols, analysis and monitoring did not receive sufficient attention owing to the complexity and costs of analysis, no standardized testing method and lack of technical expertise.

The MARGA (Monitor for Aerosols and Gases in Ambient Air), utilizes a denuder-based technique that employs steam to capture aerosol components and convert them into an aqueous state, which is then analyzed using an ion chromatography, providing detailed insights into both anionic and cationic components of the aerosols.

‘MARGA has revolutionized aerosol monitoring by detecting various ionic components,’ Viswanath noted.

‘We can now help identify the source of emission, allowing for more targeted mitigation efforts.’

Real-world applications of aerosol monitoring

Aerosol monitoring plays a significant role in assessing the impacts of emissions on societies, the causes can be localized or across regions, countries and even continents.

Metrohm was involved in many studies across the world, some of which continue even today.

Before the 2008 Beijing Olympics, the municipal authorities deployed over 20 monitoring systems across the city.

By continuously analyzing aerosol levels, they identified emission sources and adjusted industrial outputs accordingly.

This resulted in improved air quality during the games, showcasing how proactive monitoring can lead to effective pollution control.

Other study examples include:

• In Scotland: air pollution monitoring effects due to wind flow directions
• A South Korean research team worked on air pollution effects on Antarctic ice melting
• Taiwan is working on a study to check effects of the Chinese crop burning in Taiwanese air quality.

A feasibility study was undertaken in the US to measure the levels of lead in a police shooting facility, revealing higher-than-recommended levels.

Such data helped authorities implement safety measures to protect personnel from prolonged exposure to harmful airborne contaminants.

‘Across multiple environments, people are exposed to hazardous aerosols and heavy metals that often go unnoticed,’ Viswanath emphasized.

‘With precise monitoring, we can implement safety protocols that protect human health.’

The future of aerosol monitoring

Despite its benefits, aerosol monitoring still faces challenges in widespread adoption.

One hurdle is the reliance on chemicals for sample collection and analysis.

While these chemicals are not harmful, efforts are underway to minimize their usage, ensuring longer periods of unattended operation.

Chromatography needs chemicals for identification and quantification.

Manufacturers, such as Metrohm, are actively working on optimizing analysis by using separation columns which require lower chemical volumes.

This step aligns with global sustainability goals by reducing the overall chemical footprint.

Looking ahead, the future of air monitoring will likely involve a combination of traditional gas-based monitoring and advanced aerosol tracking.

As climate change intensifies and industrialization expands, comprehensive air quality management will become more critical than ever.

Let’s not forget aerosols

While traditional measurements and techniques continue to dominate air quality discussions, the awareness of aerosol monitoring needs to grow.

Integrating it as a part of regulatory frameworks and helping regulatory bodies to take informed actions is essential.

By leveraging advanced monitoring technologies, manufacturers, such as Metrohm, are bridging the gap in aerosol detection. With real-time data, mobile monitoring capabilities, and continuous advancements in technology, the future of air pollution control looks promising.

It is time for governments, industries, and environmental agencies to recognize and prioritize aerosol monitoring as an integral part of air quality management.