I would guess very few people on this earth are aware that the background level (not the urban peaks) of tropospheric ozone is inexorably rising, everywhere around the globe. And why would they be? It's invisible, and corporations have waged an even more effective campaign to hide this dangerous acceleration in pollution than their effort to deny the scientific consensus on climate change from CO2...for the very simple reason that ozone is a genuinely existential threat to all forms of life on Earth.
Recent research has demonstrated this conclusively. The increase in concentrations could be due to the escape of nitrogen fertilizers; the precursors originating from the astonishing growth in Asia; biofuel emissions; and/or the rising levels of methane from fracking and permafrost melt. In any event, although localized extreme peaks have been reduced, the constant, persistent background which has been rising since preindustrial times has now reached the most remote locations and is definitely increasing at a quickening pace. The "policy-relevant background" is so high it is approaching the air quality standards already set by the EPA. That is the reason the Obama administration would not allow Lisa Jackson to tighten the standard last year. Too many rural areas places would be out of compliance due to imported pollution with very little recourse to alleviate peak concentrations.
Even people who may be aware that ozone causes cancer and other epidemic diseases, often don't know that it is actually far more toxic to plants than humans, in a host of ways. Trees that are absorb ozone through their leaves and needles are exposed to cumulative damage year after year. It is rotting their roots and interiors. Most farmers don't realize that their crop yield and quality are significantly reduced because of pollution - anywhere from 10 to 60% now, and getting worse every year. Included in that problem is that many weeds are more resistent to ozone than the desirable crops, which they outcompete. The absolutely worst effect is that vegetation injured by ozone is then prey to insects, disease and fungus with which they once co-existed in harmony. Now, those attacks are finishing off perennial shrubs and trees at a rapidly accelerating rate.
The disastrous consequences of this for wildlife, ruminates, humans, and climate should be apparent. We have to collectively as one family decide to reduce our numbers AND our consumption levels drastically or famine is the obvious result. Unfortunately although this is well-documented from decades of studies, it represents a far more inconvenient truth than climate change which is why it has been and continues to be even more ruthlessly suppressed by industries that produce and profit from toxic emissions. It would be better if people understand that the current amount of pollution we produce is unsustainable, that we must come together as one family to preserve a habitable climate, prevent ecosystem collapse, and reduce our numbers dramatically by having much smaller families.