Many epidemiologic data support the association between ambient air pollution and all-cause mortality and morbidity, mainly from respiratory and cardiovascular diseases, particularly in the elderly, infants, pregnant women, and people with comorbidities. In addition, air pollution has been related to higher risks for lung cancer and allergic diseases. The World Health Organization (WHO) estimated that in the year 2012 ambient air pollution was responsible for 3.7 million annual deaths, representing 6.7% of all-cause deaths and tripling the 2008 estimates.1 Worldwide, air pollution causes 16% of deaths due to lung cancer, 11% of deaths due to chronic obstructive pulmonary disease, more than 20% of deaths due to ischemic heart disease and stroke, and 13% of deaths due to respiratory infections.1 In 2012, the Global Burden of Disease report2 identified air pollution among the leading risk factors for disease burden, being globally responsible alone for 3.1% of disability-adjusted life years.
Considering the strong health impact of air pollution, it is not surprising to expect substantial monetary consequences. The economics of air pollution are largely directed to measure the costs for individuals and the society at large. Health economics aims at quantifying the cost of any illness, distinguishing those associated with mortality from those associated with morbidity. There are 2 common metrics to estimate the monetary value of a life: The most common is the value of a statistical life, defined as the value that an individual places on a marginal change in his/her likelihood of dying, so that the aggregation of the individual values of the estimated marginal changes returns the overall cost of reducing by 1 the average number of deaths (ie, value of a statistical life). The second is the value of a life year, and it attaches a monetary value to the disability-adjusted life years, being a measure of how much people would pay to live another (healthy) year. The value of a statistical life and the value of a life year are correlated, and often the latter is derived from the former. Studies focusing on mortality rates use value of a statistical life estimates, whereas those counting the variation of different measures of life-years opt for value of a life year. It must be recognized that a major drawback of these measures is that they vary considerably depending on the country for which they have been estimated, with the frequent consequence that the value of a statistical life in high-income countries can be 10 times higher than that in low-income countries. Instead, morbidity costs usually are valued by summing health service costs, opportunity costs (work time or leisure time loss), and disutility deriving from actually having any disease or the anxiety generated by a polluted environment.3, 4, 5
Available studies quantify the costs of air pollution or the benefits of its reduction. From a methodological point of view, the monetary value used is the same, because they multiply the measured impact (eg, life saved or life lost) by the corresponding monetary index. The Improving Knowledge and Communication for Decision Making on Air Pollution and Health in Europe project,6 which assessed in 25 European cities the monetary benefits associated with the reduction of short- and long-term exposure to particulate matter and ozone, found that 22 additional months of life expectancy at age 30 years–thanks to compliance with WHO air quality guidelines–correspond to a total of 19,000 deaths delayed (∼400,000 life-years), with a monetary annual gain of 31 billion Euros. The Clean Air for Europe Programme project estimated that in the year 2000, ozone was responsible for 21,000 respiratory admissions in Europe, and particulate matter was responsible for 348,000 premature deaths and 100,000 hospitalizations due to respiratory and cardiovascular causes. The associated economic costs ranged between 276 and 790 billion Euros, which translated into an estimated average cost of 191 and 397 Euros per person/year.7Furthermore, the Organization for Economic Co-operation and Development (OECD),8 which used a country-specific formula to calculate value of a statistical life, showed that the economic cost of deaths from ambient air pollution for the 34 OECD countries increased by approximately 7% over the period 2005 to 2010, reaching the huge value of 1.6 trillion US dollars in 2010. Of note, a 70% and 80% increase in mortality costs over the period 2005 to 2010 also was registered in the non-OECD countries China and India, which is not surprising considering the fast industrial and economic development of these huge and densely populated countries. On the other hand, a striking example of the benefits arising from the enforcement of measures for traffic and pollution control stems from the Beijing 2008 Olympic Games. Hou et al9 observed that maintaining the exposure to particulate matter10 during the Game period under the rather unambitious limit of 100 μg/m3 was associated with a significant reduction (by 38%) of health-related economic costs compared with the periods before and after the Games.
Few studies have performed a comprehensive cost-benefit analysis, in which the costs of implementing a policy for reducing pollution are compared with the benefits obtained. For instance, Stieb et al10 developed a model to assess the costs and benefits of reducing acute cardiorespiratory morbidity related to air pollution. As an example, the observed decrease of particulate sulfate concentrations in Toronto between 1984 and 1999 resulted in annual benefits of $1.4 million dollars (95% confidence interval, 0.91-1.8 million dollars), due to reduced emergency department visits and hospital admissions for cardiorespiratory disease.10
The economic burden of air pollution goes beyond the costs generated by the effects on health because of multifaceted consequences for human welfare that encompass the ecosystem, agriculture, and buildings. The most important non-health-related effects of air pollution are an exacerbated environment for residents, tourists, and visitors; visual intrusion and decrease in the esthetic value of scenic views and landscape; lower land and property value; and damage to crops and agricultural products and damage to buildings. For instance, the impact on tourism is determined by estimating the change in revenues stemming from visitors, whereas damages to agriculture are valued at the relative market price for crops. Normally, damages to buildings are valued according to the relative restoration cost, whereas visibility and changes in real estate values require more complex techniques. For the United States, Delucchi11 carried out a comprehensive estimation of air pollution costs and claimed that visibility-related damages amount to $37 to $45 billion per year; damages to buildings are in the range of $0.4 to $8.0 billion, and crop losses amount to $2 to $6 billion.
All in all, there is robust epidemiologic evidence of the impact of air pollution on health. This is in contrast with the paucity of data on the economic impact, particularly for non-health-related ones. We encourage more studies and the development of more accurate models aimed at estimating the cost-effectiveness of reducing air pollution, with the goal to further induce governments to dedicate efforts to improve air quality. The actual European limit values for particulate matter2.5 and particulate matter10 are far too high if compared with WHO guidelines and the standards of the US Environmental Protection Agency. Low mission technologies for transportation, energy production, industry, and other sources of ambient air pollution are currently available. Their implementation would also obtain substantial reductions in greenhouse gas emission, thus creating huge advantages in terms of not only air quality but also climate changes.12
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– Massimo Franchini, MD, Pier Mannuccio Mannucci, MDcorrespondenceemail, Sergio Harari, MD, Federico Pontoni, Edoardo Croci
This article originally appeared in the September 2015 issue of The American Journal of Medicine.
