East and west Singapore join central region in recording unhealthy air quality amid haze

At 6:00 AM, the 24-hour Pollutant Standards Index (PSI) registered a reading of 105 in the west and 102 in the east. The central region, which had been the first to cross the critical threshold, recorded a higher PSI of 123. These figures underscore a significant decline in ambient air quality, prompting renewed calls for public vigilance and preventive health measures. The PSI, a composite index developed by the United States Environmental Protection Agency and adopted by Singapore’s National Environment Agency (NEA), serves as a crucial indicator of air quality, reflecting the concentration of key pollutants such as particulate matter (PM2.5 and PM10), sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3), and nitrogen dioxide (NO2). Readings between 1 and 50 are considered "Good," 51-100 "Moderate," 101-200 "Unhealthy," 201-300 "Very Unhealthy," and above 300 "Hazardous." The current readings firmly place a significant portion of Singapore in the "Unhealthy" category, signifying potential health impacts for the general population.

The current escalation follows a period of fluctuating air quality over the preceding weeks, during which PSI readings intermittently dipped in and out of the unhealthy range. A particularly notable incident occurred earlier in the week, on Tuesday, when all five regions of Singapore – North, South, East, West, and Central – simultaneously recorded unhealthy air quality levels. This was a stark reminder of the severity of the situation, marking the first time such widespread unhealthy air had been observed across the island since September 2019. That 2019 episode itself was a significant event, triggering public health advisories and disrupting daily life, although it did not reach the alarming levels seen in the catastrophic haze events of 2013 and 2015.

The persistent and widespread haze is largely attributed to ongoing land and forest fires in Indonesia, particularly in Kalimantan and southern Sumatra. The National Environment Agency (NEA), in its daily haze advisory issued on Saturday, had already forecast the 24-hour PSI to range from the high end of the moderate range to the middle of the unhealthy range for Sunday. This prediction has now unfortunately materialized, with the PSI readings leaning towards the higher end of that forecast. The NEA’s advisory further elaborated on the meteorological conditions contributing to the haze, stating that there was a tangible risk of smoke haze affecting Singapore, with prevailing winds expected to blow from the east-southeast or southeast. These wind patterns are crucial in directing the smoke plumes across the Strait of Malacca and the South China Sea directly towards Singapore.

Compounding the issue is the continued dry weather over Kalimantan and southern Sumatra. This prolonged dry spell creates ideal conditions for the rapid spread and intensification of fires, many of which are ignited for agricultural land clearing purposes, particularly for palm oil and pulpwood plantations. These practices, often employing illegal slash-and-burn methods, are a recurring environmental challenge in Southeast Asia. The NEA has confirmed that smoke plumes originating from fires in these specific areas have been observed drifting towards Singapore, providing a direct causal link to the deteriorating air quality. Satellite monitoring, often utilizing data from agencies like NASA and NOAA, plays a critical role in detecting hotspots and tracking the movement of these smoke plumes, offering vital early warnings to affected nations.

The phenomenon of transboundary haze has plagued Southeast Asia for decades, with major episodes occurring with distressing regularity since the late 1990s. The 1997-1998 haze crisis, exacerbated by a strong El Niño, was one of the worst environmental disasters in the region’s history, causing widespread economic damage and health problems. Subsequent severe episodes in 2013 and 2015 saw PSI readings in Singapore soar to unprecedented "hazardous" levels, exceeding 300 and even touching the record-breaking 400s in 2013. These events led to widespread school closures, disruptions to air travel, and a significant public health burden. The current situation, while not yet reaching those extreme peaks, serves as a grim reminder of the region’s vulnerability to this man-made ecological disaster, particularly during dry seasons often intensified by climatic phenomena like El Niño.

The health implications of prolonged exposure to unhealthy air quality are substantial and wide-ranging. The primary concern is particulate matter, especially PM2.5, which are fine particles less than 2.5 micrometers in diameter. These microscopic particles can penetrate deep into the lungs and even enter the bloodstream, leading to a host of health issues. Symptoms can range from immediate effects like eye irritation, runny nose, sore throat, and coughing to more severe conditions such as asthma attacks, bronchitis, and acute respiratory infections. For vulnerable populations, including children, the elderly, pregnant women, and individuals with pre-existing heart or lung conditions, the risks are significantly higher. Prolonged exposure can exacerbate chronic respiratory and cardiovascular diseases, potentially leading to premature mortality. Public health advisories strongly recommend minimizing strenuous outdoor activities, staying indoors with windows closed, and using air purifiers with HEPA filters. Wearing N95 masks is advised for outdoor activities when the PSI is in the very unhealthy or hazardous range, although regular surgical masks offer some protection against larger particles.

Beyond public health, the haze carries significant economic and social costs. Tourism, a vital sector for Singapore’s economy, often suffers during severe haze episodes as visitors deter their travel plans. Outdoor businesses, from construction to hawker stalls, face disruptions and reduced patronage. Aviation can be affected by reduced visibility, leading to flight delays or cancellations, impacting trade and travel. Productivity losses due to illness, absenteeism, or mandated work-from-home arrangements can also ripple through the economy. Socially, the haze disrupts daily life, forcing the cancellation of outdoor events, sports activities, and school excursions, and diminishing the overall quality of life for residents. The graphic provided by the NEA explicitly outlines guidelines for different PSI levels, advising reduced physical activity for healthy individuals and avoiding outdoor activities for vulnerable groups when PSI is unhealthy, with more stringent measures like school closures considered at higher "very unhealthy" or "hazardous" levels.

Addressing transboundary haze requires a multi-pronged approach, encompassing national preparedness and robust regional cooperation. Domestically, the NEA continues to monitor air quality closely, issue timely advisories, and implement contingency plans. Singapore’s inter-agency task force on haze, comprising representatives from various ministries and statutory boards, coordinates the national response, ensuring public health measures, educational campaigns, and operational readiness. In past severe episodes, the government has distributed N95 masks to vulnerable households and ensured ample supplies are available for purchase.

On the diplomatic front, Singapore has been a vocal proponent of regional efforts to combat haze. The ASEAN Agreement on Transboundary Haze Pollution, signed in 2002, is the region’s legally binding framework to address the issue. However, its effectiveness has been hampered by challenges in enforcement and political will. Bilateral discussions with Indonesia remain crucial, with Singapore offering technical assistance and resources to help combat fires and promote sustainable land management practices. Efforts to hold companies accountable for illegal burning in their concessions, regardless of their country of origin, are also vital. Initiatives like the Transboundary Haze Pollution Act in Singapore allow for legal action against entities, even foreign ones, contributing to haze that affects the city-state.

Environmental experts and climate scientists continually emphasize the complex interplay of factors contributing to the haze. While illegal land clearing remains the primary proximate cause, the underlying drivers include weak governance, inadequate enforcement, and market demands for cheap palm oil and pulpwood. Climate change, through its potential to increase the frequency and intensity of El Niño events and prolong dry seasons, is expected to exacerbate the problem in the long term. Dr. Lee Poh Seng, an environmental engineering expert, highlighted the need for "a paradigm shift towards sustainable agriculture and stricter regulations on land use across the region, coupled with effective law enforcement." Meteorologists indicate that significant, sustained rainfall across the fire-prone regions of Indonesia is often the most effective natural deterrent to the widespread fires, and until such weather patterns prevail, Singapore and its neighbours will remain at the mercy of prevailing winds and fire conditions.

Looking ahead, the NEA’s forecast suggests that the haze situation remains precarious. While sporadic showers could offer temporary relief in some areas, the overall dry weather pattern over Kalimantan and southern Sumatra is expected to persist. This indicates that the risk of smoke haze affecting Singapore will continue, and PSI readings could fluctuate within or even exceed the unhealthy range in the coming days. Public vigilance, adherence to health advisories, and a collective regional commitment to sustainable practices are paramount in navigating this perennial environmental challenge. The current escalation serves as a potent reminder that the battle against transboundary haze is far from over, demanding continuous effort and solidarity from all stakeholders.