|Dark smoke from smokestacks / Photo by manfredxy via 123RF|
The prevailing perspective has been that it is of the utmost importance that we curtail further ozone damage, but a study published in recent months stated that ozone concentrations have been dropping since the late ‘90s. That’s in spite of the Montreal Protocol, which was like the Paris Accord of 1989 in its attempt to do away with chemicals that damage the ozone. Now, experts are constantly revisiting the topic of how human activity impacts the ozone, and they focus on figuring out what things can be eliminated to save the ozone. This is particularly crucial information in China right now where the ozone pollution is bad and worsening.
Hazardous, ground-level ozone concentrations in northern China are painting an even more bleak picture than before as the country bands together to contend with particulate matter (PM2.5) based on a study published by a team at Peking University. China actually fulfilled major air quality milestones for the 2013-2017 period thanks to tight restrictions on transportation, industry and coal consumption, so PM2.5 levels fell; however, daytime ozone levels have skyrocketed as shown in a pollution study that compiled data on 33 northern cities. That study was done by the Center for Statistical Science and Peking University’s Guanghua Management School.
Now, when it comes to the state of the global ozone layer as a whole, there’s far less gray area. “The Montreal Protocol reduced the use of ozone-depleting chemicals and will lead to healing of the ozone layer. This is an important goal because stratospheric ozone protects us from exposure to ultraviolet radiation, which can increase the risk of cataracts, skin cancer, and other detrimental effects,” according to A.R. Ravishankara who co-chaired a panel on stratospheric ozone from 2007 to 2015 for the United Nations.
It was the World Meteorological Organization Scientific Assessment panel, and Ravishankara says that the Montreal Protocol only heals the ozone layer if the nations involved in the treaty uphold their commitments. He also, however, mentions the possibility of the scientific community having missed certain greenhouse gas emissions that might erode the ozone layer but aren’t listed in the treaty. “Our understanding of stratospheric ozone depletion has grown steadily since the mid-1970s when Mario Molina and F. Sherwood Rowland first suggested that the ozone layer could be depleted by chlorofluorocarbons, or CFCs — research that earned a Nobel Prize.”
Joseph Farman reported a so-called ozone hole developing over Antarctica in 1985. He said it was expanding every austral spring, and he was among the earliest to focus on the notion of mass thinning of the ozone. The work of Susan Solomon and her colleagues later correlated this hole with CFCs. We’ve come to understand that greenhouse gases lock heat into the atmosphere, so the Montreal Protocol has theoretically decelerated climate change as member countries did stick to their commitments largely.
Even so, though, atmospheric observations in combination with numerical models of the stratosphere and chemical reactions indicate “laboratory studies of chemical reactions and numerical models of the stratosphere, there is a general consensus among scientists that the ozone layer is on track to recover around 2060, give or take a decade,” says Ravishankara. “We also know that the future of the ozone layer is intricately intertwined with climate change.” To be clear, though, the term, ozone, is often used as short for the ozone layer, but there is also the colorless, toxic gas called ozone. It’s formed by the ultraviolet light or electrical discharges affecting oxygen molecules, particularly when sunlight interacts with nitrogen oxides and loads of other erratic, organic compounds.
|Dark smoke from chimneys of power plant / Photo by Ying Feng Johansson via 123RF|
Ozone is only one of the six pollution indicators for which China has an official air quality index — the others being PM2.5, carbon monoxide, nitrogen oxides and sulfur dioxide. They also index PM10, which is just a much larger version of PM2.5, bigger particles in the air. Ozone shot up in northern China where about ten different cities are seeing concentrations of 40 percent or more between 2014 and 2017. Some have speculated that this rise at least partly resulted from other forms of pollution being reduced. “Regional declines in the amount of PM2.5 and PM10 have reduced the volume of floating particles and increased the strength of the sunlight required to produce ozone.”
Lauri Myllyvirta is a Greenpeace clean air advocate, and he said, “If you look at the public health impact,” speaking in the context of the Chinese study released last year in which findings showed ozone becoming more and more of a health risk with correlations to upticks in both heart disease and strokes, “PM2.5 is responsible for more than a million premature deaths per year, whereas ozone is somewhere above 100,000. But last summer, ozone really spiked and it is deservedly going to get more attention.” He and others feel China should establish milestones at which they’ll cut nitrogen oxide and emissions of uncontrollable, organic compounds in the next air quality assessment to be put out this year.