A recent study led by researchers in Singapore has found that even small increases in fine particulate matter (PM2.5) air pollution are associated with a rise in emergency department visits for asthma and chronic respiratory diseases. The findings, published on September 28 in the medical journal JAMA Network Open, highlight the importance of early monitoring and precautionary actions during periods of heightened air pollution.
PM2.5 refers to airborne particles measuring 2.5 microns or less in diameter, capable of penetrating deep into the lungs. It is a key pollutant monitored in Singapore’s Pollutant Standards Index (PSI) and often rises during episodes of transboundary haze. On September 29, the PSI reached unhealthy levels across Singapore’s five regions for the first time in two weeks, with PM2.5 concentrations in the eastern part of the island peaking at 70 micrograms per cubic meter by early afternoon.
The study analyzed 74,839 emergency department visits at public hospitals in Singapore from February 2016 to December 2022, focusing on cases related to asthma and chronic obstructive pulmonary disease (COPD). Of these visits, 43,446 required hospital admission, and 1,369 patients died within 30 days. The researchers correlated these data with hourly PM2.5 readings and other environmental factors such as temperature, humidity, and rainfall obtained from the National Environment Agency’s monitoring system.
Results showed that with every 10 microgram per cubic meter increase in PM2.5 above the World Health Organization’s recommended safe threshold of 15 micrograms per cubic meter, emergency visits for asthma and COPD increased by 3.2 percent over the following two days. Asthma-related visits specifically rose by 4.4 percent within this timeframe. The association with COPD-related visits was less definitive at lower PM2.5 levels but became more pronounced at higher pollution concentrations.
The study did not find statistically significant links between short-term pollution spikes and subsequent hospital admissions or 30-day mortality. Demographically, nearly 60 percent of affected patients were male, and over 75 percent had monthly household incomes below S$2,000. However, the elevated risk of pollution-related respiratory distress appeared consistent across sex, age groups, income levels, and preexisting health conditions.
Researchers cautioned that their analysis was limited to emergency department data, excluding visits to clinics and urgent care centers, which may underestimate the total impact. The focus on PM2.5 alone also leaves open the potential influence of other pollutants. Additionally, adjustments for the COVID-19 pandemic period acknowledged but may not have fully accounted for its lingering effects on healthcare utilization patterns.
The study’s authors emphasized the practical implications of their findings. They recommended incorporating real-time air quality data into public health advisories to enable at-risk individuals to take preventive measures promptly. Marcus Ong, director of the Health Services Research and Population Health programme at Duke-NUS Medical School, noted that haze-related air pollution not only affects the environment but also leads to increased demand for emergency healthcare services within days of pollution spikes.
Singapore’s National Environment Agency provides hourly updates on PM2.5 levels, and authorities advise limiting strenuous outdoor activities when concentrations are elevated to mitigate health risks. This study underlines the critical need for continued vigilance and proactive healthcare planning in response to fluctuating air quality conditions.