MAJOR urban centres across the Klang Valley are facing elevated air pollution levels, raising concerns over the long-term health impacts of prolonged exposure to fine particulate matter
Prof Madya Dr Haliza Abdul Rahman, a lecturer in the Department of Environmental and Occupational Health at the Faculty of Medicine and Health Sciences, said vehicle emissions account for up to 70 per cent of the region’s air pollution, particularly in Kuala Lumpur.
“This finding is based on studies conducted by several faculties at Universiti Putra Malaysia (UPM),” she explained.
“The Klang Valley, as Malaysia’s most densely populated and rapidly developing area, consistently records high levels of air pollutants due to the sheer number of vehicles.”
Other areas identified with significant pollution levels include Petaling Jaya, Shah Alam, Klang, Serdang and Kajang.
“The Klang Valley has a combination of anthropogenic and environmental factors that frequently push pollution levels high, especially nitrogen dioxide, ozone and carbon monoxide.
“The primary sources, particularly nitrogen dioxide and carbon monoxide, contribute between 40 to 70 per cent of total pollution,” she said.
Prof Haliza also highlighted industrial activity in Shah Alam, Klang and Subang as contributing sulphur dioxide and volatile organic compounds to the atmosphere.
“Open burning, construction dust and rapid development in Kuala Lumpur, Petaling Jaya, Subang, Sungai Buloh and Bangi further increase airborne particulate matter,” she added.
Air quality monitoring stations operated by the Department of Environment (JAS) have shown that the Air Pollutant Index (API) in the Klang Valley typically remains at moderate levels, though readings can reach ‘unhealthy’ during haze episodes or localized pollution spikes.
“Studies from 2024 and 2025 indicate fluctuating trends. While moderate levels are the norm, unhealthy air quality is recorded during certain episodes of haze or elevated local emissions,” she noted.
Prof Haliza warned that long-term exposure to fine particulate matter carries serious health risks.
“Key impacts include increased risk of chronic lung disease, pulmonary fibrosis, and reduced lung function. Continuous exposure can raise the likelihood of Chronic Obstructive Pulmonary Disease (COPD) by 32 to 40 per cent.”
Air pollution also significantly affects cardiovascular health, she said. “Research, including studies by UPM and regional ASEAN teams, shows that pollution can thicken blood, raise blood pressure, and narrow arteries, increasing stroke risk by 20 to 30 per cent for susceptible individuals.”
To mitigate these risks, Prof Haliza recommended prioritising reductions in vehicle emissions, as traffic remains the primary contributor to pollution.
“Expanding public transport networks, introducing low-emission zones in densely populated areas, and implementing stricter vehicle emission checks could significantly reduce pollutants,” she said.
She also urged tighter industrial regulation through modern filtration technology such as electrostatic precipitators and carbon filters.
“Studies indicate factories in Shah Alam and Klang contribute up to 25 per cent of particulate matter during the dry season,” she explained.
“In the public health sector, using air purifiers in enclosed spaces such as schools, clinics, and eldercare centres can reduce fine particulate exposure by 50 to 80 per cent,” Prof Haliza added. - January 31, 2026
