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In the first flat Ser visited, where the air quality was worse than outdoors, the windows were open in the morning before the resident closed them.<\/p>\n
\u201cIt\u2019s entirely possible that the windows were closed \u2026 (when) the PM2.5 levels were higher, thereby trapping the polluted air,\u201d said Nanyang Technological University (NTU) assistant professor Leonard Ng, who used a professional-grade air quality monitor to record the measurements.<\/p>\n
In a 15th-floor flat in the same block, where the windows were also closed for an hour, the reading was lower at 149 but still elevated. When they opened the windows, it climbed to 301 as the haze worsened.<\/p>\n
As there is stronger airflow on a high floor, haze particles get blown indoors faster even as these homes are less exposed to traffic emissions, said Ng. \u201cIf the air quality is poor outside, it\u2019ll be poor inside as well.\u201d<\/p>\n
He advised opening the windows at home only when the outdoor air quality \u201cisn\u2019t that bad\u201d.<\/p>\n<\/div>\n
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