The human health effects of air pollutants are hotly debated. Since air pollution is typically a long-term, diffuse problem, it is difficult to link human mortality to any particular air pollutant. Studies of the health effects of acute chemical spills are much easier. At least you can identify the bodies.
Some argue that the health consequences of air pollution are so poorly known and difficult to value that further regulations should be avoided, so that economic growth can proceed unabated. I believe this is fundamentally wrong.
Several studies have used periods of power-plant outages and shutdowns to ascertain the human health effects of air pollution, by examining whether deaths declined during shutdown periods. For example, fewer hospital admissions for asthma occurred during the reductions in vehicle traffic that were ordered for the Atlanta Olympic Games in 1996.
Now, several new studies have used similar methods to examine rates of human mortality during the air pollution control measures for the 2008 Olympic Games in China. In Beijing, Junfeng Zhang of the Nicholas School at Duke examined various measures of cardiovascular activity before, during, and after the Olympic Games, and found rapid physiological changes in 125 subjects that made them more vulnerable to heart disease. In Guangzhou, deaths from all cause decreased from 32 to 25 during the Olympic Games, compared to similar periods during the years before and after the Olympics. Cardiovascular death, largely heart attacks, decreased from 11 to 8 during the Games and reductions were also seen in respiratory ailments. The lower death rates were attributed to lower concentrations of fine particles, known as PM2.5 in the atmosphere.
Other studies by Michelle Bell now of Yale University have linked increased cardiovascular disease to oxidizing air pollutants, such as ozone and nitric oxide. These are often derived from automobile exhaust and from utility power plants. These pollutants cause constriction of the arteries—also known as vasoconstriction—leading to arterial closure and heart attacks in unsuspecting patients. There seems to be little doubt that oxidants and fine particulate air pollution are human health hazards that must be taken seriously.
In addition to automobile exhaust and the emissions from coal-fired power plants, agricultural activities are also a source of particulate matter in the atmosphere. When fertilizer is applied or animal waste is stored in open areas, ammonia gas is lost to the atmosphere. Ammonia forms fine particulate matter when it reacts with sulfur dioxide or nitric oxide in the atmosphere. Agricultural activities are the main sources of particulate air pollutants in eastern North Carolina, and contribute to poor health in that region.
Next time you hear someone argue that the EPA’s regulation of air quality is overzealous and stifling to economic growth, ask them if they believe that the right of a few to pollute the air exceeds the right of the many to breathe clean air for a healthier life.
A conference known as Breathe—Bridging Research on Economics, Air Quality and The Health of Everyone—will be held in Raleigh on March 26, 2015. The latest science on air pollution and human health will be discussed by air quality specialists and medical practitioners. Space is limited, but you may be able to attend. For registration materials and more information, go to: http://ncbreatheconference.org/