The air in Alabama is growing cleaner as fewer cars pack the highways and some non-essential factories halt or slow their production.

“As a general trend we would expect air quality to improve and emissions to decrease as a result of the coronavirus epidemic,” said Corey Masuca, principal air pollution control engineer for the Jefferson County Department of Health.

Those impacts can be seen worldwide, from India to New York.

“All over the world, we are seeing improvements in air quality,” said Chandana Mitra an associate professor in Auburn University’s department of geosciences who studies urban sustainability. “Nitrogen dioxides [an air pollutant] are coming down in Wuhan, China and in Italy and major cities like London.

“And it doesn't have to be a big city. It can be a medium sized city as in Birmingham or Montgomery. Even here in Auburn, I'm sure there will be there will be impacts on air quality on the positive side.”

Ron Gore, air division chief at ADEM, said the state’s air is almost certainly cleaner now than it was at this time last year, but the full data and analysis aren’t available yet.

“Even before the shutdown we have met all the federal air quality standards in Alabama since 2015,” Gore said. “In other words, our air is safe to breathe as measured by the six primary pollutants that EPA and states measure across the country.

“So yes, our air quality will get cleaner as a result of the reductions in emissions from tailpipes, and from the industries that have either shut down or slowed down, but it's getting cleaner from what was already considered clean.”

Gore said estimates from the Alabama Department of Transportation indicated that the number of miles driven by vehicles in the state may have fallen by 40-50 percent from pre-COVID levels.

That should be greatly reducing the amount of nitrogen oxides in Alabama’s air. Those pollutants can be harmful on their own, but are also a component of ozone or smog, which can lead to air quality advisories in Alabama, usually during the summer.

Gore said ozone usually does not become an issue in Alabama until late May through late September.

“Definitely nitrogen oxide emissions have gone down,” Gore said. “But the accompanying lowering in ozone probably hasn't occurred because it's not that time of the year yet.”

While ADEM regulates air pollution in most of the state, the Jefferson County Department of Health does so in and around Birmingham. Masuca, principal air pollution control engineer for the County, said the department has gathered nitrogen oxide data but hasn’t analyzed it yet due to staffing issues caused by the pandemic.

Another air pollutant of concern is particulate matter, microscopic airborne particles of dust or soot that linger in the air, often from burning fossil fuels. These are also associated with human health issues, placing severe stress on the lungs and can increase the risks of heart attacks, asthma, lung cancers and other ailments.

Gore said there’s about a two-month delay in getting particulate matter samples analyzed by an outside lab, so the results from after the lockdown aren’t in yet.

Michael Hansen, executive director of Birmingham-based clean air advocacy group GASP, said the view of Birmingham from atop Red Mountain does seem to be as clear as it’s been in recent memory, but that many pollution sources still seem to be in full operation.

“Most of the industrial plants in North Birmingham, Tarrant, and East Birmingham are still operating as usual in those communities,” Hansen said. “The Bluestone Coke plant in particular has been churning out some big black plumes. Residents have complained about this a lot recently, particularly the accompanying odors.”

Emissions of greenhouse gases responsible for climate change, may be reduced this year by about 5.5 percent globally, according to one estimate. That would be the largest ever decrease in human carbon emissions, but still significantly less than the 7.6 percent reduction the United Nations says is needed every year for the next decade to meet targets set in the Paris climate accords.