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SINGAPORE \u2013 The air quality in Singapore deteriorated on Oct 3, with the 24-hour Pollutant Standards Index (PSI) reading at 11am dipping into the unhealthy range in the central region (102).<\/p>\n
Although they remained in the moderate range, the National Environment Agency\u2019s (NEA) PSI readings for all other regions also increased.<\/p>\n
At 6am, the readings in the north, south, east and west ranged from 73 to 88 before rising to between 76 and 94 at 11am.<\/p>\n
PM2.5 readings, which are used as a gauge for immediate activities, were in the elevated range in three of the five regions.<\/p>\n
The three regions were east, west and central, with a PM2.5 reading of 66, 57 and 63 respectively.<\/p>\n
Air quality is considered unhealthy when the 24-hour PSI is in the range of 101 to 200, while an hourly PM2.5 reading between 56 and 150 indicates an elevated concentration of fine particles.<\/p>\n
The PSI \u2013 a 24-hour rolling average of six key air pollutants and used in planning for outdoor activities the next day \u2013 last crossed into the unhealthy range on Sept 30<\/span><\/a>. The day saw the entire island swathed in a fine milky haze, with the reading hitting a peak of 134 in central Singapore as at 1am.<\/p>\n