In the first two minutes, after a 747 takes off, it emits as much air pollution as 3,000 cars, says a study. Over the past decade or so, air transport has been increasingly recognized as an environmental threat. It accounts for an estimated 13 per cent of the world’s carbon dioxide emissions from all transportation sources.
In its total impact on climate, ecology and health, today’s mega-airports may be one of the most ill-conceived forms of large-scale infrastructure humankind has ever devised — yet it is also one of the least accountable.
Chicago’s O’Hara Airport sit on the site of former apple orchards. The St. Louis Airport was once soybean fields. Denver International Airport (DIA) is where winter wheat was once grown. China’s Macau International spans two ecologically sensitive wetlands.
Airports are both multiplying and expanding at a breathtaking rate. In the past few years, huge new airports have appeared all over the world — from Denver to Abu Dhabi to Bangkok. Constructing an airport is not on the same scale as building a new office tower or highway; it’s more like building a city.
Airports consume land, energy and dumping capacity at rates rarely equalled anywhere else.
In the first five minutes of a flight, a commercial airliner burns — turns to CO2 — as much oxygen as 17,000 hectares (44,000 acres) of forest produce in a day. The exhaust from a single plane may spread to over as much as 34,000 square kilometres (13,000 square miles). For each passenger on a trans- Pacific flight, about a ton of CO2 is added to the earth’s atmosphere.
Each gallon of jet fuel burned pollutes over 8,400 gallons of air to a level of toxicity that would be dangerous, if not lethal, to breathe. The only reasons we’re not seeing it kill anyone is that it’s so rapidly dispersed through the atmosphere.
Studies of neighbourhoods near airports such as Chicago’s O’Hare and Seattle’s Sea-Tac have shown that jet exhaust is subjecting residents to extremely high concentrations of carcinogens and at least 200 other toxic compounds. Significant increases in cancer risk are found among people living near airports with as few as 15 jet flights per day, yet most major cities launch hundreds, and some of them — where there’s more than one major airport — launch thousands.
The scream of jets — of fuel igniting and turbine blades striking the air as planes take off — has become the most noticeable of the environmental impacts of airports worldwide, for obvious reasons. Whereas the effects of contaminated air or water may take years to emerge, airplane noise produces instant irritation.
Airports may affect the health of anyone living within about a 20-mile radius. In the United States today, 70 per cent of the population lives within 20 miles of a major airport.
A study has found that “infant mortality near the airport was 50 per cent greater, heart disease was 57 per cent greater, cancer deaths were 36 per cent greater”. For people living near the airport, overall life expectancy was found to be 5.6 years shorter.
In Germany, when the new Munich airport went into operation, a study of third and fourth grade children living in the flight path found significant increases in blood pressure and stress hormones, compared with a similar group of children living in the same area before the airport began operation. “These hormones are linked to adult illness, some of which are life-threatening, including high blood pressure, elevated lipids and cholesterol, heart disease, and reduction in the body’s supply of disease-fighting immune cells,” noted the report.
The Munich study also found that the children subjected to flight-path noise did not learn to read as well, because they tended to tune out speech. This is probably the most definitive proof that noise causes stress and is harmful to humans. — Samina Iqbal
Controlling malaria
In Sub-Saharan Africa, malaria causes between 0.5 to two million deaths annually, states a recent issue of the Journal of American Medical Association. Programmes have been initiated to halve malaria mortality by 2010. The preventive strategy includes the use of insecticide treated bed nets that have proved to be useful in previous trials. There have been concerns that these measures could delay the acquisition of immunity, which could result in a more severe manifestation of malaria. To describe the clinical features and case fatality of severe Falciparum Malaria, a study was carried out on 1984 patients admitted to 10 hospitals in Tanzania. The median age of the patients was one year in the high transmission, three years in moderate transmission and five years in low transmission areas. Forty nine per cent of cases presented with cerebral malaria, severe anaemia or respiratory distress. Overall there were 139 deaths (seven per cent) with a higher proportion in the low transmission areas. It was also more in cases with cerebral malaria.
The areas of transmission were influenced by age and altitude. Most cases lived below 600 meters and eighty six per cent were below five years of age. Case fatality was also highest at this altitude, more because of severe anaemia, respiratory distress and cerebral malaria.
The study provided evidence of a complex relationship between intensity of exposure to Plasmodium Falciparum, age, clinical manifestations and fatality. A reduction in transmission is likely to increase the median age of malaria victims from one to three years, where severe malaria is less likely and over all case fatality is low. This is an encouraging outcome for malaria control measures. — Dr Fatema Jawad
