“We’ve shown that the gene being changed is directly associated with asthma and severity of the asthma,” Dr. Kari Nadeau of Stanford University, the senior study author, told a press conference at the 2013 meeting of the AAAAI in San Antonio, Texas.

The new study shows that exposure to polycyclic aromatic hydrocarbons (PAHs) in the air directly led to a change in a gene known as FOXP3. This gene exists inside regulatory T-cells, whose job is to suppress inappropriate immune responses, such as the airway inflammation associated with asthma. This alteration in the gene makes it harder for the T-regulatory cells to do their job, leading to worsened asthma symptoms.

The study also associated PAH exposure with higher overall levels of IgE antibodies, which play a major role in any allergic response.

For the study, researchers observed a group of children and teens at two sites in California: Fresno, which is known for heavy air pollution and a high rate of asthma (about 22 percent), while Stanford, a lower-pollution area, was used as a control group. Measurements were taken of PAH levels in the air, the children were given lung function tests, and also gave blood and urine samples.

The children who had been exposed to PAHs for three months before the testing were more likely to have altered FOXP3 genes, decreased T-regulatory cell function and high levels of IgE antibodies. All three differences make asthma more likely, and its impact more severe.

“Exposure to high PAH quantities may be having an effect at the molecular level, possibly leading to new cases of asthma,” said Nadeau in a press release. This altered version of FOXP3 was even found in individuals from the area who didn’t have asthma – and it is unknown whether this change is reversible.

More than 100 chemicals are classified as PAHs, which form when an organic substance is burned incompletely. Sources include oil, gas, coal, tobacco, or even meat from a barbecue (when drippings fall onto the flames, PAHs are formed which then adhere to the meat). Man-made PAHs can also be found – in tars as well as some plastics, dyes and pesticides.

See Allergic Living‘s full coverage of the 2013 AAAAI allergists conference.

Even Canadian Prime Minister Stephen Harper, our most prominent person with asthma, has switched gears to appeal to the green vote. But what about a green revolution on the ground level? What will it take to make our cities tolerable for those with asthma who are advised to stay indoors every time there’s a smog warning?

You might wonder. Despite all the clamour about climate change, we still shrug off the monumental human toll that dirty air is exacting on our communities right now. Health Canada estimates that air pollution, mainly from burning fossil fuels to power industry, homes and cars, kills about 5,900 Canadians a year in eight cities: Quebec City, Montreal, Ottawa, Toronto, Hamilton, Windsor, Calgary and Vancouver.

That’s nine times the annual number of homicides. And for the three million Canadians with asthma, which includes 12 per cent of all Canadian children, the dirty air is particularly dangerous. In Ontario alone, asthmatics last year made more than 73,000 visits to the emergency room, according to hospital statistics.

Think of what that means: on 73,000 occasions, an adult or a child was wheezing or coughing or gasping so badly that he or she had to rush to emergency just to breathe. Although there are many asthma triggers, smog is a significant one; it’s associated with a quarter of respiratory admissions to Toronto hospitals – and half of the admissions on peak air pollution days.

And yet, we tolerate the situation. In the Windsor-Quebec corridor, which has Canada’s worst smog problem, a summer smog advisory has become commonplace. In 2005, a record year, there were 53 smog advisory days in Ontario, 24 in Quebec and three in Atlantic Canada (where most of the pollution blows in from the United States.) Last year was a little better: Ontario and Quebec each had 17 smog advisory days.

But that’s little consolation when many asthmatics have trouble breathing outdoors even on days that are considered to be “safe”. They have every right to demand change. Smog, for the person with asthma, means denial of the most basic right: to step outside, breathe a lungful of air and not choke.

The battle against smog and its components – ground-level ozone, nitrogen oxides, sulphur dioxide, volatile organic compounds (VOCs), carbon monoxide and fine particulate matter – has a lot in common with the worldwide campaign to save the upper ozone layer by cutting greenhouse gases, mainly carbon dioxide.

The man-made emissions that cause both are produced from burning fossil fuels, which power industry, heat and light homes, and run cars and trucks. Burn less fossil fuel, and you can reduce greenhouse gases and smog at the same time.

The biggest single human source of the smog is transportation. According to a 2005 air quality report from the Ontario government, vehicles create 17 per cent of VOCs and 29 per cent of nitrogen oxides. These combine in the sun and heat to create the ground-level ozone part of smog.

Vehicles also cause 56 per cent of carbon monoxide, while all forms of transportation, including cars, trucks, boats and trains, are responsible for 18 per cent of fine particulates or soot, another key part of the dirty haze. Ontario, the province with the worst smog problem, is taking action on the road.

It has cracked down on clunkers, and issues rebates to those who buy hybrids. The Harper government (which announced its own hybrid rebates), meanwhile, promises stricter fuel efficiency standards by 2010, but hasn’t specified a standard.

Industry, especially coal-fired power plants, also plays a big role in creating smog, and is a big target for regulators. Ontario has ordered smelters and cement plants to reduce their emissions of nitrogen oxides and sulphur dioxides to a new standard by 2015. Each of seven industrial sectors affected will have its own limit, so if new plants are built, they will only be permitted a small percentage increase in emissions. If industry also curtails energy use, it will help both the smog and the climate change issues.

But in the end, the biggest target is the hardest to hit. That’s the way we live our lives. We are the ones driving the gas-guzzling SUVs from monster homes in the suburbs to work and soccer practice. We supply the coal-fired power plants with their raison d’être by thoroughly chilling our houses in summer. Consider that Ontarians, per capita, consume 55 per cent more electricity than people living in the state of New York.

Next Page: The Green Prescription