PSI hits 102: Haze pushes air quality in central Singapore into unhealthy range新加坡中部地区空气污染指数（PSI）高达102：雾霾导致空气质量恶化，进入不健康范围。
Singapore's air quality is back in the unhealthy range at 1pm on Saturday (Sept 19), as the 24-hour Pollutant Standards Index (PSI) reading hits 102 in central Singapore.Elsewhere, western Singapore recorded the next highest reading of 90 — in the moderate range.Data from the National Environment Agency (NEA) shows one-hour PM2.5 concentration reading in central Singapore entering the elevated band...
Singapore's air quality is back in the unhealthy range at 1pm on Saturday (Sept 19), as the 24-hour Pollutant Standards Index (PSI) reading hits 102 in central Singapore.
Elsewhere, western Singapore recorded the next highest reading of 90 — in the moderate range.
Data from the National Environment Agency (NEA) shows one-hour PM2.5 concentration reading in central Singapore entering the elevated band at 10am, before climbing gradually to as high as 149 at 12pm.
The one-hour PM2.5 concentration reading at 1pm ranges from 71 to 141, which is in the elevated band. Readings between 56 to 150 denote the elevated band, while readings between 151 to 250 are in the high-band.
What PM2.5 readings mean
The National Environment Agency (NEA) groups PM2.5 readings into four bands: normal (0-55 µg/m3), elevated (56 to 150), high (151 to 250), and very high (251 and above).
The public can check PM2.5 readings for guidelines on immediate outdoor activities.
They should note that the health impact of haze depends on their health status, as well as the duration and intensity of outdoor activity.
When PM2.5 readings are in the elevated band, members of the public should reduce strenuous outdoor activity for the next hour.
Vulnerable persons such as the elderly, pregnant women, children, and persons with chronic lung or heart disease should avoid strenuous outdoor activity.
However, if readings hit the high band, all healthy persons should avoid strenuous outdoor activity for the next hour, while vulnerable persons should avoid all outdoor activity.
High moderate to low-unhealthy forecast
In its daily haze situation update on Friday evening , NEA had said the country's 24-hour PSI forecast is expected to be in the high moderate to low unhealthy range.
This is due to smoke plumes from fires in Kalimantan drifting towards Singapore. Some smoke plumes were also observed over southern Sumatra, the agency added.
Given that prevailing winds are expected to blow from the east-southeast or southeast, NEA said the risk of smoke haze affecting Singapore remains.
新加坡空气质量于周六（9 月 19 日）下午 1 点再次达到不健康水平，新加坡中部地区的 24 小时污染物标准指数 (PSI) 读数达到 102。
新加坡西部其他地区录得第二高的读数为 90，属于中等范围。
国家环境局 (NEA) 的数据显示，新加坡中部地区 PM2.5 浓度一小时读数在上午 10 点进入高位区间，然后逐渐攀升，到中午 12 点达到 149 的高位。
下午1点的PM2.5一小时浓度读数在71至141之间，属于偏高范围。读数在56至150之间表示偏高范围，而读数在151至250之间表示高浓度范围。
PM2.5读数意味着什么
国家环境局 (NEA) 将 PM2.5 读数分为四个等级：正常 (0-55 µg/m3)、升高 (56 至 150)、高 (151 至 250) 和非常高 (251 及以上)。
公众可以查看 PM2.5 读数，以了解近期户外活动的指导方针。
他们应该注意到，雾霾对健康的影响取决于他们的健康状况，以及户外活动的持续时间和强度。
当 PM2.5 读数处于较高水平时，公众应在接下来的一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。
但是，如果读数达到高值，所有健康的人在接下来的一个小时内都应该避免剧烈的户外活动，而易感人群应该避免所有户外活动。
高、中、低至不健康预测
国家环境局在周五晚间发布的每日雾霾情况更新中表示，该国24小时空气污染指数预计将处于高、中、低不健康范围内。
这是由于加里曼丹岛火灾产生的烟雾飘向新加坡所致。该机构补充说，苏门答腊南部也观测到了一些烟雾。
鉴于预计盛行风向将来自东南偏东或东南方向，新加坡国家环境局表示，烟雾影响新加坡的风险依然存在。