Participants of today’s Himpunan Rakyat Bersatu would be risking their health tremendously for exposing themselves to the haze, said Datuk Seri Dr Abu Hassan Asaari Abdullah.

He said people should be aware that the haze poses a multitude of health risks, including a heart attack which could lead to death.

The Kuala Lumpur Hospital head of emergency department said, over exposure to the haze could also lead to long-term damage in a person’s health.

“Haze is extremely dangerous as the smog contains tonnes of pollutants that can trigger sore throats, coughs, asthma and sore eyes, among other things. It also narrows your blood vessels and trigger high blood pressure.

“All these happen when the airborne pollutant particles enter the lungs. The effects aren’t necessarily immediate, problems can arise about a week or even a month after being exposed,” the expert said on the programme “Landskap” on TV1.

Besides Dr Abu Hassan Asaari, another panel speaker on the programme was University of Malaya’s Department of Anthropology and Sociology senior lecturer, Dr Noor Sulastry Yurni Ahmad.

READ: Five things you need to know about the 'red shirt' rally before Sept 16

In today’s gathering, dubbed the ‘red shirts’ rally, participants are said to began gathering around Bukit Bintang area around 11am before marching to Padang Merbok at 3pm.

Among the roads to be closed to the public today include Jalan Parlimen.

KL City Hall had given the event organisers, the National Silat Confederation (Pesaka) the green light to use the field as the rally venue on Monday.

Inspector General of Police Tan Sri Khalid Abu Bakar had also assured that police personnel would be on ground to secure the event and people’s safety.

Prime Minister Datuk Seri Najib Razak had warned rally-goers against bringing any form of written material, including banners and posters that could incite racial tension.

Former premier Tun Dr Mahathir Mohamad, however, had said the rally should just be called off because it doesn't champion the cause it claims to be championing.