Singapore wakes up to unhealthy air quality, central region PSI hits 154

Air quality across all five regions in Singapore are in the unhealthy range.

The Pollutant Standard Index (PSI) reading for southern Singapore slipped into the unhealthy range at 10pm, while air quality in northern Singapore entered the unhealthy range at 1am.

At 7am on Tuesday (Sept 15) morning, the PSI reading was between 104 and 153 — within the unhealthy range — with central Singapore recording the highest PSI of 153.

But one-hour PM2.5 — an indicator of fine micro-pollutants in the air — has been improving across Singapore..

Data from the National Environment Agency (NEA) shows that at 7am, only central Singapore (57) has a marginally elevated PM2.5 reading.

Meanwhile, one-hour PM2.5 reading for the four remaining regions is between 24 and 38, within the normal band. Readings of between 56 and 150 denote the elevated band.

High moderate to mid-unhealthy PSI forecast

In its daily haze situation update on Monday evening, NEA had said the country's 24-hour PSI forecast is expected to be in the high moderate to mid-unhealthy range .

Explaining this, the agency noted that moderate to dense smoke plumes from fires in Kalimantan drifted towards Singapore on Monday.

This, it said, is due to a shift in the prevailing winds to east-southeasterly directions, adding that smoke haze was also observed drifting from southern Sumatra.

In addition, dry weather conditions are expected over Singapore and the surrounding region in the coming days.

With prevailing winds forecast to continue blowing from the southeast to east-southeast, Singapore is likely to remain affected by smoke haze, NEA said.

What the PM2.5 readings mean for outdoor activities

PM2.5 is the current air quality that matters — when planning to conduct or participate in outdoor activities immediately.

When PM2.5 readings are in the elevated band, members of the public should reduce strenuous outdoor activity for the next few hours.

Vulnerable persons such as the elderly, pregnant women, children, and persons with chronic lung or heart disease should avoid strenuous outdoor activity.

Members of the public should note that the health impact of haze is dependent on one's health status, the PSI level, and the length and intensity of outdoor activity.

For the general population, symptoms that may arise from short-term exposure include throat or eye irritation.

These symptoms are typically temporary and should subside once a person leaves the affected environment.

新加坡所有五个地区的空气质量均处于不健康范围。

新加坡南部地区的污染物标准指数（PSI）读数在晚上 10 点降至不健康范围，而新加坡北部地区的空气质量在凌晨 1 点进入不健康范围。

周二（9 月 15 日）早上 7 点，PSI 读数在 104 到 153 之间——处于不健康范围内——其中新加坡中部记录到的最高 PSI 为 153。

但新加坡各地的PM2.5一小时浓度（空气中细颗粒物浓度的指标）一直在改善。

国家环境局 (NEA) 的数据显示，早上 7 点，只有新加坡中部地区 (57) 的 PM2.5 读数略高。

同时，其余四个地区的PM2.5一小时读数在24至38之间，属于正常范围。读数在56至150之间则属于超标范围。

高、中等至中度不健康 PSI 预测

周一晚间，国家环境局在其每日雾霾情况更新中表示，该国24小时空气污染指数（PSI）预计将处于中度至中度不健康范围。

该机构解释说，周一，加里曼丹岛火灾产生的中等至浓烟向新加坡飘去。

报告称，这是由于盛行风向转为东南偏东风，并补充说，还观察到有烟霾从苏门答腊南部飘来。

此外，预计未来几天新加坡及周边地区将出现干燥天气。

新加坡国家环境局表示，由于预计盛行风向将继续从东南吹向东南偏东，新加坡可能仍将受到烟雾的影响。

PM2.5读数对户外活动意味着什么

PM2.5 是当前最重要的空气质量指标——当您计划立即进行或参与户外活动时。

当 PM2.5 读数处于较高水平时，公众应在接下来的几个小时内减少剧烈的户外活动。

老年人、孕妇、儿童以及患有慢性肺病或心脏病等弱势群体应避免剧烈的户外活动。

公众应注意，雾霾对健康的影响取决于个人的健康状况、PSI 值以及户外活动的持续时间和强度。

对于普通人群而言，短期接触可能出现的症状包括喉咙或眼睛刺激。

这些症状通常是暂时的，一旦离开受影响的环境，症状就会消退。