Imagine living near a trash dump so putrid that you would rather move to war-torn Syria.

That's what Fayyad Ayyash, his wife Riham and their four young daughters plan to do next week, leaving behind their home in Lebanon for neighbouring Syria.

Their modest two-storey house in the town of Naameh, about 20 kilometres (12 miles) south of the Lebanese capital, directly overlooks the infamous and odorous landfill by the same name.

"We're going next week. In Syria, there's a possibility I might die. Here, we'll definitely die," Fayyad tells AFP.

From his grassy backyard, dozens of large trucks carrying tonnes of waste can be seen -- and smelled -- lining up to add their load to the "trash mountain."

The July 2015 closure of the notorious landfill lies at the heart of Lebanon's trash crisis, which has seen rivers of trash spread across the Mediterranean country, triggering protests nationwide.

Then last month, the government made a controversial decision to reopen it -- and this was the last straw for residents like Fayyad.

Pulling out a bright blue inhaler, he says his family has been suffering from respiratory problems for months because of the dump.

His daughters, whose ages range from just under two to 10 years, all have trouble eating and sleeping.

"It's always worse at night than during the day. The whole area is swarming with the same smell and the same sickness," he says.

Fayyad says it's become so bad, he's decided to flee across the border to the town of Libeen in southern Syria, a country where a conflict has been raging since 2011.

- Costly medical bills -

The Naameh landfill opened in 1997 and was meant to be a temporary dump, but an alternative site was never opened.

For 20 years, the waste generated in Beirut and Mount Lebanon -- the country's most populous areas -- was dumped in Naameh.

The verdant valley swelled into a trash mountain of more than 15 million tonnes.

Furious residents forced the closure of the site in July 2015, saying it was leading to high cancer rates, skin diseases and breathing problems.

Uncollected rubbish began piling up around Beirut and its suburbs, emitting a horrible stench that sparked protests in downtown Beirut demanding a long-term solution.

After months of political wrangling, Lebanon's cabinet announced a four-year plan to end the waste crisis -- and its first step was reopening Naameh for two months.

"When the dump reopened, my baby immediately started throwing up again," Fayyad says.

Fayyad and his Syrian wife, Riham, are both Druze, an offshoot of Islam.

Riham estimates that she spends about $1,000 (around 880 euros) per month on doctor's visits, inhalers, and other medication for her children.

Pointing to her bare finger, she says she had to sell her wedding ring to cover the costs.

"I wish my kids would eat food as much as they take medicine," she says.

Riham's family hails from Libeen, in Syria's southern Sweida province. That's where she will travel to next week, in the hope that the open plains there will be good for her children.

- Suitcase 'packed and ready' -

Sweida, the heartland of Syria's Druze minority, has come under attack by jihadists of the Islamic State group but has seen less fighting than other parts of the country.

"No, it isn't safe, but I'm forced to leave... I have a suitcase packed and ready on top of the closet," Riham says.

Farouk Merhebi from the American University of Beirut says the smell has probably made life incredibly uncomfortable for hundreds living within a one-kilometre radius of the dump.

Before the crisis began, trash trucks would dump between 2,800 to 3,000 tonnes of waste per day in Naameh, says Merhebi, who is AUB's director of environmental health, safety and risk management.

"Now it's about 8,000 to 9,000 tonnes. The operations almost tripled because they're playing catch-up with the trash that had accumulated," he says.

"The waste that has accumulated in streets has fermented, so the smell is offensive... The smell is worse because it's been there for seven to eight months."

But the long-term health effects of the dump on the surrounding area remain untested.

Merhebi is part of a team at AUB hoping for funding to complete research in the area "to test the surface water, ground water, and some samples of the soil as well as samples of ambient air."

But Fayyad and his family say they cannot wait.

"Riham's family said they were thinking of coming to Lebanon," he says.

"But we told them, 'do you want to die here from the smell?'"