An especially thick haze has hung over Beirut in recent weeks. The yellowish cloud, perhaps most visible from vantage points above the city, has drawn attention from experts and everyday residents alike.

Issam Lakkis, a professor of mechanical engineering at the American University of Beirut, told The Daily Star that he and his colleagues had “observed and sensed higher levels of pollution [early last week].” Najat Saliba, an associate professor in analytical chemistry at AUB, said the air had felt especially “heavy” in recent days.

The air-quality app Sensio recorded that on many days in late May, pollution levels in Beirut had “maxed out.” The app’s pollution forecast suggests that levels will hit the highest rating again, starting midweek.

According to previously unpublished data collected by Mohammad Roumie, a researcher at the Lebanese Atomic Energy Commission, in May the levels of particulate matter (PM) with a diameter of 2.5 micrometers and below were up by 1 microgram per cubic meter compared with a year earlier.

What does this mean for average Beirutis, and what can they do to stave off the negative consequences?

NUCLEAR REACTION

ANALYSISParticles smaller than 2.5 micrometers in diameter - about 30 times smaller than the diameter of a human hair - are more dangerous than larger particles, Roumie explains. “Below this size they can infiltrate your body. They can go to your lungs, into blood cells and can generate many diseases - asthmatic, cardiovascular, and even cancer.”

The European Environment Agency’s air-quality standards set the maximum acceptable annual average of PM 2.5 at 10 mg/m3. Beirut’s May 2019 average - 21 mg/m3 - was over double that yearly recommended average.

The 2019 winter averages similarly exceeded that recommendation - hitting as high as 24 mg/m3 in January and only as low as 15 mg/m3 in January.

“Within the month, some days may be PM 6, and some may be more than PM 30,” Roumie said, adding that the day-to-day disparity is a result of various climatic factors.

An air sanitary expert from the Environment Ministry attributed the high pollution levels in Beirut from the past two weeks to a sandstorm she said had blown across the Sahara Desert.

Roumie has been collecting air samples on the roof of LAEC’s laboratories near Beirut’s airport every week since 2014. He and his team use the laboratory’s ion beam accelerator to determine the elemental composition of the air particulate matter collected in the samples.

He said that to this point, it has been impossible in Lebanon to identify the elemental makeup of pollutants. “You cannot say at the moment: ‘I have calcium ... coming from the cement factory.’”

But the technology used by Roumie’s lab is able to differentiate between calcium from a cement factory and calcium from a Saharan dust storm, he explained.

He said his project ultimately aims to determine the sources of air pollution by percentage. “When you know the contribution of the sources to our air pollution, then you can say to the decision maker, ‘We have to take action against these kind of sources,’” Roumie told The Daily Star.

He believes that the findings could help the government tax individual and commercial behaviors causing air pollution, and help the country conform to EU PM standards.

“To be effective you have to make people pay for what they are doing. They are polluting, they are responsible for this pollution,” alluding to cement factories and power plants as probable culprits.WHAT’S THE CAUSE?Statistics aside, what does the worsening pollution mean for the Beirutis venturing out onto the sidewalks? Carcinogen levels in the capital are seven times higher than in Los Angeles, Najat Saliba, the analytical chemistry professor, told The Daily Star.

In one of her studies, she found that carcinogens released by diesel generators - ubiquitous throughout the country because of the state’s failure to provide 24-hour electricity - are the equivalent of smoking two cigarettes a day.

“At times, the power outage is only three hours. In other areas it can be more like 10 hours,” she said. In other words, diesel generator pollution may be considerably higher in areas outside the capital than inside Beirut.

As for why air pollution is generally worse in the summer, Saliba pointed to two main factors: a lack of wind and solar radiation.

“There is high solar radiation, which can ‘cook’ pollution faster. In the morning, when cars start moving, they produce [nitric oxide]. With solar radiation it turns into [nitric dioxide], which is the bad guy.”

Lakkis, the mechanical engineering professor at AUB, who led a team that produced a mathematical model of Beirut to predict air pollution levels, also pointed to the lack wind as a primary culprit for why contamination levels are higher during the summer months.

Lakkis said that whether pollution stays or leaves is the function of wind and temperature.

He also listed a number of other factors that exacerbate air pollution during the summer months.

“Pollution is a function of three parameters, loosely,” he said.

“One is emission sources. Are we emitting less or more in the summer? The main emission sources in Beirut are the cars ... and the diesel generators,” he added.

Although Lakkis says he doesn’t think more cars are on the road during the summer, he believes that Beirutis likely consume more electricity in the summer, “especially if turning on the AC. The cars themselves are burning more fuel if the AC is turned on in car.”

Variations in temperature throughout the day are the second “very important parameter,” he added. The cool air in the mornings is heavier than the warm hair later in the day, and therefore is dispersed less easily.

“The worst case scenario is when there is no wind and low temperature. You can see this happening in summer, when the earth is still cold and the pollutant tends to stay. ... Later in the day, when it is warmer, [the pollutant] goes up due to buoyancy, and things improve a little bit.”

what CAN BE DONE?With pollutant levels already soaring above safe averages and only worsening, can anything be done to shield residents until a reformist strategy such as the one proposed by Roumie can be realized? The expert from the Environment Ministry declined to comment on the ministry’s plans to combat air pollution in the immediate future. However, the “National Strategy for Air Quality Management” released by the ministry says it aims to “reduce the adverse per capita environmental impact of cities, including by paying special attention to air quality and municipal and other waste management by 2030.”

As for the short term, air quality experts agree that certain personal measures can be taken to reduce the adverse health effects of air pollution in cities.

Besides societal strategies that he believes are “widely known by now,” Lakkis recommended a number of personal steps that may help reduce the negative health effects of air pollution.

Especially modern and well-maintained cars should have air filters that sift out a “significant portion” of pollutants, even if they don’t get rid of all of them. “Usually filters have trouble filtering the very small particles - what we call PM 2.5,” Lakkis said.

Air conditioning, meanwhile, can increase “self-pollution” - a vehicle’s own engine fumes entering the passenger compartment - as well as overall emissions on the road. Staying at home is another option, as not even the face masks favored by the residents of many polluted cities are an effective prevention. Although most masks can filter PM 10 and below, they fail to filter out the more dangerous, fine inhalable particles, that is of PM 2.5 and below.

“I sit on advisory board for the World Health Organization. This discussion was brought up several times. Masks may be effective, but there is not enough evidence to recommend them,” Saliba said.

At home, Lakkis recommended installing a “good-quality indoor filter,” and opening and closing windows at the right time. “If a diesel generator is running next door, close the windows.”

“I don’t open windows in my home. I don’t walk outside unless I have to,” Saliba added.