Benefits Analysis of Nitrogen Dioxide Control Programmes: A Case-study of Chiyoda-ku, Tokyo

The objectives of this case-study were to apply a benefits valuation method to assess the economic benefits of past environmental policies relating to nitrogen dioxide (NO 2 ) in Chiyoda Ward (Chiyoda-ku), Tokyo, and to validate the results by comparing them with results obtained by other researchers. Our point estimates of the numbers of additional cases of respiratory illness which would have occurred had there been no NO2 pollution control were 110 000 cases of phlegm in adults (population 35 910) and 71 000 cases in workers (population 23 143), and 16 000 cases of lower respiratory illness in children aged 5-12 years (population 2812) during a 1-year period. Our point estimate of medical costs in adults and children plus the cost of lost wages for workers and working mothers was ¥6.2 billion (US$52 million). For duration of illness and medical treatment costs, and certain illness occurrence rates, our estimated and calculated values fell within the range of values reported by other researchers. For lost wages among sick workers and working mothers, and some other rates of illness, our estimated values were higher. Overall, our results appear more likely to be underestimates than overestimates due to several unquantified benefits. Our calculations of health impacts avoided suggest that pollution control policies successfully prevented a large expense to the society in extra medical care and lost work time.