Haze update for Sept 9: 24-hour PSI in central region edges closer to unhealthy range

Singapore's 24-hour Pollutant Standard Index (PSI) is expected to remain in the high moderate to low unhealthy range, the National Environment Agency (NEA) said in its daily update on Wednesday (Sept 9).

Air quality in Singapore remained in the moderate range for a fourth consecutive day on Wednesday, but readings across all five regions have been rising since Tuesday evening.

At 6pm, 24-hour PSI reading for the central region is 98. Readings of between 101 and 200 are in the unhealthy range.

Meanwhile, 1-hour PM2.5 readings for both the central and eastern regions are in the elevated range, with readings of 85 and 58 respectively.

1-hour PM2.5 readings of between 56 and 150 denote elevated range.

Explaining the worsening air quality, NEA said that moderate to dense smoke plumes continue to be detected from fires in southern and central Sumatra and Kalimantan.

Smoke haze was observed to drift towards Singapore, the agency added.

Noting that dry conditions are expected to persist over Kalimantan and southern Sumatra, coupled with the prevailing southerly, south-easterly winds, NEA expects the risk of transboundary smoke haze affecting Singapore to remain — should the fires persist.

Those who are planning to conduct or participate in outdoor activities immediately can check the 1-hour PM2.5 concentration readings and vulnerable persons guide.

Meanwhile, those who are planning outdoor activities for the next day should use the 24-hour PSI forecast and the corresponding health advisories for planning.

新加坡国家环境局 (NEA) 在周三（9 月 9 日）发布的每日更新中表示，新加坡 24 小时污染物标准指数 (PSI) 预计将继续处于高、中、低不健康范围内。

新加坡周三的空气质量连续第四天保持在中等水平，但自周二晚上以来，所有五个地区的空气质量读数都在上升。

下午 6 点，中部地区的 24 小时 PSI 读数为 98。读数在 101 到 200 之间属于不健康范围。

与此同时，中部和东部地区的 1 小时 PM2.5 读数均处于较高水平，读数分别为 85 和 58。

1 小时 PM2.5 读数在 56 到 150 之间表示偏高。

国家环境局解释空气质量恶化的原因时表示，苏门答腊岛南部和中部以及加里曼丹岛的火灾持续产生中等至浓重的烟雾。

该机构补充说，观测到烟雾向新加坡方向飘移。

鉴于加里曼丹岛和苏门答腊南部预计将持续干燥天气，加上盛行南风和东南风，新加坡国家环境局预计，如果火灾持续，跨境烟霾影响新加坡的风险依然存在。

计划立即进行或参与户外活动的人员可以查看 1 小时 PM2.5 浓度读数和易感人群指南。

同时，计划第二天进行户外活动的人们应该参考 24 小时 PSI 预报和相应的健康建议进行规划。