Haze update for Sept 15: PSI expected to remain in high moderate to mid-unhealthy range

Air quality in Singapore improved slightly on Tuesday (Sept 15), a day after the 24-hour Pollutant Standards Index (PSI) slipped into the unhealthy range in all five regions in Singapore.

At 6pm, the 24-hour PSI ranged between 92 and 131, placing Singapore's overall air quality in the moderate to unhealthy range.

The highest reading of 131 was recorded in central Singapore, followed by the western (114) and eastern (113) regions.

Both northern (93) and southern (92) Singapore remained in the moderate range.

Meanwhile, the one-hour PM2.5 concentration readings ranged between 43 and 74 — with only the southern region in the normal band — while the four remaining regions recorded readings in the elevated band.

The country's 24-hour PSI forecast is again expected to be in the high moderate to mid-unhealthy range over the next 24 hours.

Explaining this in its daily haze situation update on Tuesday evening, the National Environment Agency (NEA) said that while overnight showers over some areas in the surrounding region contributed to improvements in the haze situation, prevailing winds — from the east-southeast and southeast directions — had brought smoke haze from Kalimantan and Sumatra to Singapore.

NEA added that dry conditions are expected to persist over central and southern Sumatra and southern Kalimantan in the coming days.

This means that the risk of smoke haze affecting Singapore remains.

Members of the public are advised to check one-hour PM2.5 concentration readings and the accompanying personal guide when deciding on outdoor activities in the next few hours.

For planning outdoor activities the following day, they should refer to the 24-hour PSI forecast and the corresponding health advisories.

新加坡的空气质量在周二（9月15日）略有改善，此前一天，新加坡所有五个地区的24小时污染物标准指数（PSI）均跌至不健康范围。

下午 6 点，24 小时空气污染指数 (PSI) 在 92 到 131 之间，表明新加坡的整体空气质量处于中等至不健康水平。

新加坡中部地区记录到的最高读数为 131，其次是西部地区（114）和东部地区（113）。

新加坡北部（93）和南部（92）的气温均处于中等水平。

与此同时，一小时 PM2.5 浓度读数在 43 至 74 之间——只有南部地区处于正常范围内——而其余四个地区的读数均处于升高范围内。

预计未来 24 小时内，该国 24 小时 PSI 指数将再次处于中度至中度不健康范围内。

新加坡国家环境局 (NEA) 在周二晚间发布的每日雾霾情况更新中解释说，虽然周边地区一些地方的夜间降雨有助于改善雾霾情况，但盛行的东南风和东南风将加里曼丹和苏门答腊的烟雾带到了新加坡。

尼泊尔国家环境局补充说，未来几天苏门答腊中部和南部以及加里曼丹南部预计将持续干旱。

这意味着烟雾影响新加坡的风险依然存在。

建议公众在决定未来几小时内进行户外活动时，查看一小时 PM2.5 浓度读数和相应的个人指南。

为了规划第二天的户外活动，他们应该参考 24 小时 PSI 预报和相应的健康建议。