Haze watch Oct 17: Hourly PM2.5 in western region back in high band, PSI remains unhealthy

After 18 hours in the elevated band, hourly PM2.5 in western Singapore climbed back into the high band (151 to 250µg/m3) at 11am on Saturday (Oct 17) morning.

The western concentration reading returned to the elevated band (56 to 150µg/m3) at 5pm on Friday and was gradually easing into the lower-half of the said band.

But at 11am, one-hour PM2.5 soared from 111 to 158µg/m3.

Meanwhile, the 24-hour Pollutant Standards Index (PSI) is in the unhealthy range across Singapore, with the highest reading of 184 in the central region, followed by 176 in western Singapore.

While members of the public can use the PSI forecast to plan activities, they should track the latest hourly PM2.5 concentration readings before taking part in outdoor activities.

Although a low 24-hour PSI may generally indicate a good condition, a high one-hour PM2.5 reading could indicate that conditions have recently worsened, even though the longer-term average has not risen yet.

When PM2.5 concentration readings are in the high band, healthy persons should avoid strenuous outdoor activity for the next hour, while vulnerable persons should avoid all outdoor activity for the next hour.

Those who are vulnerable may also wear a N95 mask to reduce exposure.

During a whole-of-government press conference on the haze situation on Friday afternoon, Sustainability and the Environment Minister Grace Fu urged Singaporeans to be prepared for the haze to "persist for some time".

"The situation is fluid. Depending on the weather, we can expect air quality to fluctuate, including the possibility of reaching hazardous level (PSI >300)," the minister said.

Sport Singapore (SportSG) on Friday afternoon announced the temporary closure of all its outdoor and non-aircon ActiveSG facilities , citing the haze situation.

At midnight, SportSG lifted the closure, announcing that all facilities will resume operations on Saturday .

However, this could change should air quality deteriorate in any region. Members of the public can check for the latest facility closure updates at the ActiveSG Circle website .

在经历了 18 小时的高位运行后，新加坡西部地区的 PM2.5 每小时浓度于星期六（10 月 17 日）上午 11 点再次攀升至高位（151 至 250µg/m3）。

周五下午 5 点，西部地区的浓度读数恢复到较高水平（56 至 150µg/m3），并逐渐下降到该水平的下半部分。

但上午 11 点，PM2.5 一小时浓度从 111 微克/立方米飙升至 158 微克/立方米。

与此同时，新加坡全境 24 小时污染物标准指数 (PSI) 均处于不健康范围，其中中部地区读数最高，达 184，其次是新加坡西部地区，为 176。

虽然公众可以使用 PSI 预报来计划活动，但他们在参加户外活动之前应该关注最新的每小时 PM2.5 浓度读数。

虽然 24 小时 PSI 值较低通常可能表明空气质量良好，但 1 小时 PM2.5 读数较高可能表明空气质量最近有所恶化，即使长期平均值尚未上升。

当 PM2.5 浓度读数处于较高水平时，健康人群应在接下来的一个小时内避免剧烈的户外活动，而易感人群应在接下来的一个小时内避免所有户外活动。

易感人群也可以佩戴N95口罩以减少感染风险。

周五下午，新加坡政府就雾霾情况召开新闻发布会，可持续发展与环境部长傅海燕敦促新加坡人做好准备，雾霾可能会“持续一段时间”。

“情况瞬息万变。根据天气情况，空气质量可能会波动，甚至可能达到危险水平（PSI > 300）。”部长说。

新加坡体育理事会（SportSG）周五下午宣布，由于雾霾情况，暂时关闭所有室外和非空调的ActiveSG设施。

午夜时分，新加坡体育理事会宣布解除关闭令，所有设施将于周六恢复运营。

然而，如果任何地区的空气质量恶化，情况可能会发生变化。公众可登录ActiveSG Circle网站查看最新的设施关闭信息。