Pasir gudang: The recent chemical leakage incident at an industrial facility in Pasir Gudang serves as yet another reminder that industrial pollution risks remain present and require serious attention from all stakeholders.

According to BERNAMA News Agency, initial reports indicate that the leak involved spent inorganic acid classified as scheduled waste SW206.

Although prompt actions were taken by the Department of Environment (DOE), the Fire and Rescue Department of Malaysia, the Hazardous Materials (Hazmat) team, and the industry involved to contain the situation, this incident should be viewed as more than an isolated event. Instead, it should trigger a broader discussion on how prepared Malaysia is to leverage modern technologies to prevent pollution incidents before they occur.

Over the past decade, Malaysia has experienced several environmental incidents that have had significant impacts on society. The Sungai Kim-Kim pollution incident in 2019 resulted in thousands of students and residents seeking medical treatment following exposure to hazardous pollutants. The tragedy exposed the serious consequences that can arise when pollutant releases are not detected or controlled at an early stage. Malaysia has also repeatedly faced transboundary haze episodes that have affected public health, economic activities, and the education sector. More recently, the Putra Heights incident reminded us that the release or accumulation of flammable substances can pose serious safety risks.

While the actual cause of any incident must be determined through official investigations and technical assessments by the relevant authorities, such events highlight the importance of early detection of leaks and potentially hazardous gas accumulations. The question is simple: How many more warnings do we need before shifting from a reactive approach to a preventive one?

Malaysia already possesses a well-established air quality monitoring system through the Continuous Air Quality Monitoring Station (CAQMS) network operated by the Department of Environment. These stations employ high-precision reference instruments that comply with international standards and serve as the backbone of the nation's air quality monitoring framework. The data generated play a critical role in monitoring the six major criteria air pollutants: PM2.5, PM10, sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3).

However, today's environmental challenges are becoming increasingly complex. Modern industrial areas are not only associated with conventional air pollutants. Emissions of volatile organic compounds (VOCs), ammonia (NH3), hydrogen sulphide (H2S), methane (CH4), carbon dioxide (CO2), and various industrial chemicals also deserve greater attention. In many cases, these substances contribute to odour complaints, health risks, ground level ozone formation, secondary particle formation, and potential safety hazards if accumulated at elevated concentrations. Therefore, future monitoring strategies must move beyond the routine monitoring of only six criteria pollutants.

One common misconception is that sensor technology is intended to replace reference monitoring stations. This is simply not true. As a scientist involved in environmental sensor development for more than a decade, I would like to emphasise that sensors were never designed to replace CAQMS. CAQMS remains the nation's primary monitoring system because of its accuracy, reliability, and scientific credibility. At the same time, we must recognise that establishing, operating, and maintaining reference grade monitoring stations is expensive. Consequently, the number of stations that can be deployed will always be limited. This is where sensor technology becomes highly valuable.

With proper calibration procedures, quality assurance protocols, and integration with reference instruments, modern sensors can provide highly useful information for identifying pollutant concentration ranges, detecting abnormal changes, and delivering early warnings to stakeholders. In short, sensors should not be viewed as a replacement for CAQMS, but rather as a complementary technology that strengthens and supports the existing monitoring network. The combination of both technologies enables more comprehensive environmental surveillance with significantly greater spatial coverage.

Many developed countries have embraced dense air quality sensor networks as part of their environmental monitoring strategies. These sensors are deployed in urban areas, industrial zones, schools, ports, highways, and environmentally sensitive locations. Data is transmitted in real time through Internet of Things (IoT) platforms and displayed on centralised dashboards. More importantly, these datasets are increasingly integrated with artificial intelligence (AI), machine learning algorithms, and forecasting models to identify anomalies, predict pollution episodes, and establish effective early warning systems. In certain situations, these technologies are capable of providing several hours of advance warning before pollution reaches critical levels. This represents the future direction of environmental monitoring globally.

In reality, Malaysia does not lack expertise or technological capability. At Universiti Kebangsaan Malaysia (UKM), environmental monitoring systems based on sensors, IoT, and AI have been developed for more than a decade by the UKM Atmospheric Research Group. Within this research group, I lead a team focusing on sensor development for air and water quality monitoring. These systems have been applied in environmental monitoring projects, scientific research, industrial management programmes, and community-based initiatives. Furthermore, the technologies developed have been successfully commercialised and adopted by various organisations both locally and internationally, including in Brunei Darussalam.

One example is our AiRBOXSense platform, which enables real time monitoring of air quality parameters, including VOCs and other pollutants. Our group has also established sensor calibration facilities to ensure that sensors provide reliable and scientifically defensible measurements. These achievements demonstrate that the technology has matured and is fully capable of supporting Malaysia's environmental monitoring needs. What is needed now is a strategic and systematic effort to expand its implementation nationwide.

Investments in sensor technologies are not solely about managing pollution incidents. They are directly linked to several national development priorities. Environmental, Social and Governance (ESG) initiatives require reliable environmental data. Carbon Net Zero targets require broader greenhouse gas monitoring capabilities. Climate change adaptation strategies depend on detailed environmental and meteorological information. Smart city initiatives rely on real time environmental intelligence to support effective urban management.

Likewise, the Industrial Revolution 4.0 transformation depends on sensors, IoT, big data analytics, and artificial intelligence as key enablers of data driven decision making. All of these agendas share one common requirement: They need data. And good data can only be obtained through robust monitoring systems.

The Sungai Kim-Kim, Putra Heights, and Pasir Gudang incidents may differ in location and context, but they all deliver the same message. Malaysia must strengthen its capabilities in early detection and real time environmental monitoring. The debate today should not focus on whether sensors can replace reference instruments. Instead, the focus should be on how sensor technologies, IoT, artificial intelligence, and reference monitoring stations can be integrated to create a smarter, more responsive, and future ready environmental monitoring ecosystem. The technology already exists. Local expertise already exists. The only question remaining is whether we are willing to continue waiting for the next incident to occur, or whether we are prepared to act before it happens.