PETALING JAYA: The dry spell, vehicle emission and stagnant air are causing the haze in the Klang Valley, said Department of Environment Air Division director Che Asmah Ibrahim.
Since the Klang Valley is surrounded by hills, the air around it will stagnate pollutants, including nitrogen dioxide and carbon monoxide produced by motor vehicles.
This in turn will create a hazy environment especially during dry weather, she told The Star.
Che Asmah said the air quality had deteriorated slightly from Monday and most weather stations in the country recorded moderate Air Pollution Index (API) reading in the 50-100 range.
(A good reading is from 0-50, unhealthy 101-200, very unhealthy 201-299 and hazardous from 300 and above.)
She said there might also be a slight influence of transboundary haze from Sumatra due to the south-westerly winds.
We have detected an increasing number of hotspots in Sumatra since Friday which has resulted in haze in Malacca and Johor. However, the haze in Klang Valley is mostly caused by local factors, she added.
Che Asmah said it was not possible that local open burning had contributed to the haze but cautioned the public against carrying out such activities.
Meteorological Services Department deputy director-general Dr Yap Kok Seng said Malaysia would face a dry period until September due to the south-west monsoon.
We expect a break from the dry weather in a weeks time for a few days of rain, he said.