Earlier this week, two vans loaded with sophisticated instruments drove along the streets of New York and New Jersey in sweltering heat, sniffing the air for toxic chemicals.
They detected spikes in methane, a potent greenhouse gas, most likely from buses leaking or burning natural gas. They spotted plumes of nitrous oxide, likely from wastewater. And throughout the trip, they recorded elevated levels of ozone, a major component of smog, and carcinogenic formaldehyde — both of which form easily in hot weather.
The bottom line is this: our streets are full of pollution hotspots. And high temperatures make pollution worse.
“If you want chemical reactions to go faster, you need to heat them up,” said Peter DeCarlo, an atmospheric pollution researcher at Johns Hopkins University who is leading an effort to use trucks to measure emissions in Louisiana’s petrochemical corridor. “When it’s hotter, the principle is the same,” he said.
Air pollution increases as temperatures rise, exacerbating the dangers of global warming, one reason cities and counties across the eastern United States that were hit by a heat wave this week issued air pollution alerts.
For the past three days, New York City has warned that ozone levels in the city are “unhealthy for sensitive groups.” Detroit and Chicago also issued air quality alerts this week. Drivers in Ohio, Michigan, Kentucky and Indiana were urged to avoid refueling before 8 p.m. and to carpool or not drive when possible to reduce exhaust fumes.
Air pollution is linked to atmospheric chemistry, said Professor DeCarlo, whose van, accompanied by two New York Times reporters, traveled through the South Bronx, East Harlem and Midtown. Pollutants from burning fossil fuels react with heat and sunlight to form ground-level ozone. Higher temperatures accelerate the process.
Formaldehyde emissions, which can come from a variety of sources including wildfires and household products, are expected to increase as temperatures rise. “The same chemicals that produce high levels of ozone also produce other hazardous air pollutants, such as formaldehyde,” said Professor DeCarlo.
Localized hot spots can sometimes be seen. In some Manhattan neighborhoods, for example, formaldehyde levels were twice as high as in surrounding areas, perhaps due to a particularly dirty burn caused by a nearby malfunctioning appliance.
Heat pollution is becoming a growing global concern. Health risks from extreme heat aren’t the only consequence of record-breaking temperatures. The World Meteorological Organization says rising temperatures will also lead to increased air pollution. In a report last year.
“Climate change and air quality cannot be addressed separately,” WMO Secretary-General Petteri Taalas said at the time. “They are mutually reinforcing and must be addressed together to break this vicious cycle.”
Breathing high levels of formaldehyde and ozone can lead to respiratory irritation and inflammation, decreased lung function, and difficulty preventing and controlling asthma attacks. Exposure to these substances is particularly concerning for people with lung diseases such as asthma or chronic bronchitis, said Keeve Nachman, a Johns Hopkins environmental health and risk assessment researcher and co-leader of the mobile monitoring project.
Coincidentally, New York is in the grip of a heatwave this week, and the research team’s pollution-sniffing vehicle came to the city to demonstrate their technology.
Professor Nachman said that although formaldehyde is carcinogenic to humans, cancer mainly comes from long-term exposure rather than temporarily increased concentrations.
It’s also important to realise that chemical exposures don’t happen all at once, he said, and that the chemicals we’re continually exposed to can work together to harm our health. “Hot weather creates a situation where people are breathing in multiple harmful chemicals at the same time,” Professor Nachman said. “Formaldehyde and ozone are good examples of this.”
One of the trucks will return to Louisiana later this year to measure up to 45 pollutants produced by the state’s petrochemical industry, which is controlled by the Bloomberg Philanthropies’ Beyond Petrochemicals campaign. Under initial peer review Research published this monthResearchers have found that emissions of the carcinogenic gas ethylene oxide used in the production of plastics are much higher than previously known.
Built by environmental measurement technology company Aerodyne, the high-tech mobile lab vehicle is driven by researchers to view pollution levels in real time and can even track plumes to determine their source. “It’s a bit like a video game,” Professor De Carlo said. “We can measure everything at once.”
Blakey Migliozzi Contributed reporting.
