The number of patients admitted for respiratory diseases in the past few days at the Saigon General Hospital in District 1 has increased by 5-10 percent compared to normal days, said Nguyen Khac Vui, its deputy director.

Ngo The Hoang, head of the respiratory and internal medicine department at the Thong Nhat Hospital in Tan Binh District, said that since last weekend, the department has received more patients coming in with respiratory problems and on Sunday, it was even overloaded and all doctors and nurses had to work around the clock.

The HCMC Children's Hospital treated over 90 patients with respiratory problems on Tuesday compared to 60-70 on normal days.

Doctors are generally agreed that air pollution in HCMC in particular and the southern region in general has become a serious health risk now.

Since last week, air quality in HCMC worsened badly as a thick haze enveloped the entire city.

On Sunday, meteorologist Le Dinh Quyet of the Southern Hydrometeorological Center explained the haze as being caused by a tropical convergence zone, a band of clouds consisting of showers formed in Vietnam's south central region, causing heavy rain in the morning and evening. With low daytime temperatures, this led to a high level of humidity, causing the haze, he said.

"The phenomenon also shows air pollution and high dust levels in the air," Quyet said.

HCMC’s Air Quality Index (AQI) level was at 130-150 as of Wednesday morning.

The AQI was measured by IQAir AirVisual, a Switzerland-based air quality monitoring facility that generates data from public, ground-based and real-time monitoring stations.

It is a metric used by multiple governmental agencies to determine how polluted the air is. An AQI level above 100 is considered polluted or unhealthy for humans. Children, seniors and individuals with respiratory and heart diseases are recommended to avoid sustained and high-intensity outdoor exercises when AQI levels reach 150 or above.

Also on Wednesday, the city’s PM2.5 level was recorded at 47.4 micrograms per cubic meter of air. The World Health Organization Air Quality Guideline recommends an annual mean exposure threshold for PM2.5 of 10 micrograms to minimize health risks.

PM, or particulate matter, refers to a mixture of solid particles and liquid droplets found in the air. PM2.5, also described as super fine particles, is a fraction of the width of a human hair, and is released by vehicles, industry and natural sources like dust.

The current air pollution is not only causing acute respiratory diseases, but also worsening the situation for those with chronic diseases.

Nghe, 73, who suffers from a chronic respiratory disease (pulmonary obstruction), had to receive emergency aid several days ago.

She did not get better until Tuesday. "Every time there are changes in the air, those with chronic respiratory diseases like me have it worse," she said.

A doctor checks with a respiratory patient at a hospital in Ho Chi Minh City,
September 24, 2019. Photo by VnExpress/Le Phuong.

AirVisual has predicted that HCMC will continue to experience air pollution at orange and red levels in coming days, with orange meaning conditions harmful for certain groups, and red meaning conditions harmful for everyone.

The other major city in Vietnam, Hanoi, the capital, is also suffering from bad air pollution.

Hanoi’s AQI was 174 on Wednesday’s morning and its PM2.5 at 97.2 micrograms per cubic meter of air.

Things are not much better in other countries in the region.

Indonesia has spent months battling fires, often caused by slash-and-burn farming practices, as the El Nino weather pattern exacerbates the annual dry season and helps create a choking haze across the region.

Haze conditions have also badly affected Malaysia and Singapore, with unhealthy levels registered in both countries over the last week. Authorities in Malaysia have closed thousands of schools, begun cloud seeding to combat the situation and distributed face masks, according to Reuters.