Haze update for Sept 9: 24-hour PSI in central region remains in unhealthy range

The 24-hour Pollutant Standard Index (PSI) for Singapore is forecast to remain in the high moderate to low unhealthy range, said the National Environment Agency in its daily update on Thursday (Sept 10) evening.

Air quality in Singapore's central region re-entered the unhealthy range at about 11pm on Wednesday night, and continued through Thursday.

As at 6pm, the 24-hour PSI reading was 104 in the central region.

Over the same period, 24-hour PSI readings have remained in the moderate range for the northern, eastern, southern, and western regions.

Meanwhile, 1-hour PM2.5 readings for the central region have been elevated since 2pm, while readings in the four other regions are in the normal range at 6pm.

Readings of between 56 to 150 denote the elevated range.

Explaining this, NEA said that moderate to dense smoke plumes continue to be detected from fires in southern Sumatra and Kalimantan.

It added that smoke plumes from southern Sumatra were also observed to be drifting towards Singapore.

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.

What to do when air quality is unhealthy

Healthy persons can continue with normal activities if PSI remains in the moderate range.

However, they should reduce prolonged or strenuous outdoor physical exertion if PSI crosses into the unhealthy range.

Elderly persons, pregnant women and children can also continue with normal activities if the PSI remains in the moderate range.

They should minimise prolonged or strenuous outdoor physical exertion if the PSI is in the unhealthy range.

Those with chronic lung or heart disease may similarly continue with normal activities when the PSI is moderate.

But they should avoid prolonged or strenuous outdoor physical exertion if the PSI reading crosses into the unhealthy range.

新加坡国家环境局在周四（9月10日）晚间的每日更新中表示，预计新加坡24小时污染物标准指数（PSI）将继续处于高、中、低不健康范围内。

新加坡中部地区的空气质量在周三晚上 11 点左右再次进入不健康范围，并持续到周四。

截至下午 6 点，中部地区的 24 小时 PSI 读数为 104。

同期，北部、东部、南部和西部地区的 24 小时 PSI 读数均保持在中等范围内。

与此同时，中部地区的 1 小时 PM2.5 读数自下午 2 点以来一直偏高，而其他四个地区的读数在下午 6 点已恢复正常。

读数在 56 到 150 之间表示偏高范围。

国家环境局解释说，苏门答腊南部和加里曼丹的火灾持续产生中等至浓重的烟雾。

报告还指出，来自苏门答腊南部的烟雾也正向新加坡飘去。

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。

空气质量不健康时该怎么办？

如果 PSI 保持在中等范围内，健康人可以继续进行正常活动。

但是，如果 PSI 值超过健康范围，他们应该减少长时间或剧烈的户外体力活动。

如果 PSI 保持在中等范围内，老年人、孕妇和儿童也可以继续进行正常的活动。

如果 PSI 值处于不健康范围，则应尽量减少长时间或剧烈的户外体力活动。

同样，当 PSI 处于中等水平时，患有慢性肺病或心脏病的人也可以继续进行正常的活动。

但如果 PSI 读数超过健康范围，则应避免长时间或剧烈的户外体力活动。