Singapore wakes up to unhealthy air quality as 24-hour PSI hits 105 in the central region

Air quality in Singapore has slipped back to the unhealthy range again .

After recording four days of moderate air quality, 24-hour Pollutant Standard Index (PSI) hit 102 in the central region at 11pm on Wednesday (Sept 9), and has continued into Thursday morning.

At that time, 1-hour PM2.5 in both the central and western regions also reached the elevated range — at 83 and 57 respectively. Readings between 56 and 150 denote the elevated range.

Meanwhile, 24-hour PSI for the central region remains in the unhealthy region at 105 at about 8.40am. It is in the moderate range for all other regions.

1-hour PM2.5 reading is in the normal range for all regions at that time.

In its daily haze update on Wednesday evening , the National Environment Agency (NEA) had said that moderate to dense smoke plumes continue to be detected from fires in southern and central Sumatra and Kalimantan.

Smoke haze was also observed to be drifting 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.

Category-based advisory

Based on the 24-hour-PSI forecast on Friday, 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.

新加坡的空气质量再次下滑至不健康水平。

在连续四天空气质量良好之后，周三（9 月 9 日）晚上 11 点，中部地区的 24 小时污染物标准指数 (PSI) 达到 102，并持续到周四早上。

当时，中部和西部地区的1小时PM2.5浓度也分别达到了偏高水平，分别为83和57。56至150之间的读数表示偏高水平。

与此同时，截至上午8点40分左右，中部地区的24小时空气污染指数（PSI）仍处于不健康范围，为105。其他所有地区的PSI均处于中等范围。

当时所有地区的1小时PM2.5读数均在正常范围内。

国家环境局 (NEA) 在周三晚间的每日雾霾更新中表示，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。

该机构还观察到烟雾正向新加坡方向飘移。

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。

基于类别的咨询

根据周五的 24 小时 PSI 预测，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。