环境分析

有一天24小时的臭氧浓度的时均值，如何计算当日的臭氧 8小时浓度均值？谢谢！

8小时浓度均值即连续8个小时浓度的平均值。对于臭氧，应取连续8个小时平均值的最大值. 例如N1=avg{c1,c2,c3,,,,c8}  N2=avg{c2,c2,c3,,,,c9}  N3=avg{c3,c2,c3,,,,c10}  依次推出，N17=avg{c17,c2,c3,,,,c24}   臭氧日8小时最大值=max{N1,N2,N3,,,,,N17}.
这里有一点需要注意：上面到N17就结束了，但是否继续循环下去，即一直到N24=avg{c24, c1‘,c2',c3',,,,,c7}，才算一整天，即今天与明天是否有交叠的情况，这个得查美国的做法。

EPA上的Q&A里面有解释
Q: How do I compute the daily maximum 8-hour average ozone concentration?

The new Aerometric Information Retrieval System (AIRS) will do this computation for you. First, running 8-hour averages are computed from the hourly ozone concentration data for each hour of the year and the result is stored in the first, or start, hour of the 8-hour period. In the event that only 6 (or 7) hourly averages are available, the 8-hour average is computed using 6 (or 7) as the divisor. Generally, if fewer than 6 hours of ozone concentration data are available, then the 8-hour daily maximum concentration for the day is assigned the value of ‘ missing.' However, just because we are missing more than 2 hours of monitoring data, we do not want to ignore 8-hour concentrations that clearly exceed the level of the standard. When more than 2 hours of monitoring data are missing, we compute the 8-hour average concentration by substituting one-half the minimum detectable limit for the missing hourly concentrations and using 8 as the divisor. In this case, if the computed 8-hour average concentration is greater than 0.08 ppm, it is retained, otherwise the 8-hour concentration for this 8-hour period is assigned the value of ‘missing.' In all cases, the computed 8-hour average ozone concentration is reported in parts per million (ppm) to three decimal places (the insignificant digits to the right of the third decimal place are truncated).