Problem
A newspaper headline reads "Acid Precipitation Not a Threat." The article states that the city's air pollution control board has been monitoring sulfur oxides and nitrogen oxides in the air and recording the pH of precipitation for the past five years. Air samples have been collected daily at two sites: at the busiest downtown intersection and at the entrance to a privately owned electrical power-generating station. On most days, the power station is downwind from the downtown area. Over the period studied, sulfur oxides and nitrogen oxides have increased at both sites, with the power station always having higher levels than the downtown site. However, at no time in the past five years have any of the pollutant levels exceeded the nationally acceptable standards. Moreover, the pH of precipitation has remained essentially the same (slightly acidic) at both monitoring sites throughout the period. City officials have concluded that there is no immediate reason for alarm, that acid precipitation has not been a problem, but that monitoring should continue. The news article, however, goes on to point out that not everyone agrees with the city officials. One resident living 10 miles outside the city is quoted: "The trees on our streets and in our yards are dying from acid precipitation. Five years ago, all our trees were healthy, but we've lost a dozen in this neighborhood in the past two years. We're directly downwind from that power plant, and I know acid rain killed my trees. My neighbors and I are going to sue the power company for losses.
i. Do you think these residents have the scientific evidence needed to win their lawsuit? Why or why not?
ii. Would they have a clear-cut case if a monitoring site had been set up in their neighborhood and data collected there showed an increase in acid precipitation during the five-year period?
iii. If the residents hired you as a scientific consultant, what advice would you give them?