PETALING JAYA: Port Dickson and Seremban moved into the unhealthy air category based on the air pollutant index (API) reading at 5pm Monday. Port Dickson registered an API of 101 and Seremban 107.
An API reading of between 0 and 50 is considered good, 51 to 100 (moderate), 101 to 200 (unhealthy), 201 to 300 (very unhealthy), and 301 and above (hazardous).
Areas showing API readings close to unhealthy levels are Banting (96), Balok Baru in Kuantan (97), Bukit Rambai in Melaka (90), and Bandaraya Melaka (90).
However, Cheras' API reading which rose up to 105 at 2pm improved to moderate (73) at 5pm.
Other areas with moderate to unhealthy air are Kuala Selangor (75), Port Klang (77), Petaling Jaya (77), Shah Alam (76), Batu Muda (74), Putrajaya (75).
The API reading could change due to shifting wind conditions. The Department of Environment issues hourly API reading on its website.
The API is calculated based on five major air pollutants, namely Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Ground Level Ozone (O3), Carbon Monoxide (CO) and particulate matter with a diameter below 10 micrometers (PM10).