i rou sm eis isuns ss ssad inb i in 2025, as fluctuating annual PM2.5 concentrations reflected both significant environmental gains and emerging challenges. frst time, every country successfully met the WHO Interim Target 1 by maintaining annual concentrations below 35 μg/m3. This progress was headlined by Laos, Myanmar, Indonesia, Thailand, Malaysia, and Cambodia, all of which continued their year-over- year improvements. Laos, Cambodia, and Indonesia recorded the most substantial gains, with particulate matter decreases of 18%, climbing from 14 μg/m3 in 2024 to 19 μg/m3 in 2025. Indonesia ultimately recorded the highest annual concentration at 30 μg/m3. While this represents a successful reduction from Range of 2025 average PM2.5 (μg/m3) across regional cities previous years, the country remains vulnerable to polution from issues are particularly acute during the dry season from May through October, when biomass burning often triggers regional concerns. Ultimately, transboundary haze remains a shared struggle for all Southeast Asian nations, signaling that while Vietnam followed with the_ second-highest recorded annual average in the region at 29.7 μg/m3. This was largely driven by pe ssa nn n sg go o e combustion. These factors contributed to severe seasonal spikes; in January andDecember2025,eight Vietnamese citiesrecorded monthly average concentrations exceeding 80 μg/m3. cities in Southeast Asia were included in this year's Report, fewer than 47%, only 190 cities, were equipped with official government monitoring stations. This gap underscores a critical need: while policy initiatives to reduce emissions are essential, they must be supported by a robust, well-maintained data network to accurately measure progress and validate environmental outcomes. Despite these gaps, the monitoring footprint is expanding. Indonesia and Vietnam led the region in growth, each contributing xa si jo anu s d u o s mu a varies by country; Indonesia's new cities are primarily derived a pe s sum sns o o neighboring nations rely on a mix of both government and non- government monitoring stations. This diversification of data sources is a vital step forward, yet it highlights the ongoing effort required to standardize and stabize environmental reporting
原图定位