Haze update for Sept 22: Thundery showers keep haze at bay, 24-hour PSI forecast to remain in moderate range

Air quality in Singapore remained in the moderate range on Tuesday (Sept 22) as moderate to heavy thundery showers again fell across the Republic throughout the afternoon.

At 6pm, the 24-hour Pollutant Standards Index (PSI) ranged between 59 and 77 — in the moderate range — with central Singapore recording the highest reading of 77.

Meanwhile, one-hour PM2.5 is in the normal band for all five regions.

In its daily haze update on Tuesday evening, the National Environment Agency (NEA) said the 24-hour PSI forecast for Singapore is expected to remain in the moderate range.

This is also the first time since daily updates began on Sept 4 that a moderate-only forecast is being issued.

Explaining this, NEA said that showers are expected over Singapore and parts of the surrounding region on Wednesday, which could lower the risk of smoke haze.

However, it cautioned that moderate to dense smoke plumes were still observed from fires in Kalimantan and southern Sumatra.

Data from the ASEAN Specialised Meteorological Centre shows that the number of hotspots in Kalimantan fell from 699 on Sept 20, to 198 on Sept 21.

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.

周二（9月22日），新加坡空气质量仍处于中等水平，下午新加坡全境再次出现中到大雨，并伴有雷阵雨。

下午 6 点，24 小时污染物标准指数 (PSI) 介于 59 至 77 之间——处于中等范围——其中新加坡中部地区的读数最高，为 77。

与此同时，五个地区的PM2.5一小时浓度均处于正常范围内。

新加坡国家环境局（NEA）在周二晚间发布的每日雾霾预报中表示，新加坡24小时空气污染指数（PSI）预计将保持在中等水平。

这也是自 9 月 4 日开始每日更新以来，首次发布仅显示中等强度的天气预报。

新加坡国家环境局解释说，预计周三新加坡及周边地区将有阵雨，这可能会降低烟雾的风险。

然而，报告警告说，加里曼丹岛和苏门答腊南部地区的火灾仍然会产生中等至浓密的烟雾。

东盟专业气象中心的数据显示，加里曼丹岛的热点数量从 9 月 20 日的 699 个下降到 9 月 21 日的 198 个。

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。