ANNEX VIIOZONE TARGET VALUES AND LONG-TERM OBJECTIVES

A.Definitions and criteria

1.Definitions

AOT40 (expressed in (μg/m3) · hours) means the sum of the difference between hourly concentrations greater than 80 μg/m3 (= 40 parts per billion) and 80 μg/m3 over a given period using only the one-hour values measured between 8.00 and 20.00 Central European Time (CET) each day.

2.Criteria

The following criteria shall be used for checking validity when aggregating data and calculating statistical parameters:

Parameter

Required proportion of valid data

One hour values

75 % (i.e. 45 minutes)

Eight hours values

75 % of values (i.e. six hours)

Maximum daily 8 hours mean from hourly running 8 hours

75 % of the hourly running eight hours averages (i.e. 18 eight-hourly averages per day)

AOT40

90 % of the one hour values over the time period defined for calculating the AOT40 value28

Annual mean

75 % of the one hour values over summer (April to September) and 75 % over winter (January to March, October to December) seasons separately

Number of exceedances and maximum values per month

90 % of the daily maximum eight hours mean values (27 available daily values per month)

90 % of the one hour values between 8.00 and 20.00 CET

Number of exceedances and maximum values per year

five out of six months over the summer season (April to September)

In cases where all possible measured data are not available, the following factor shall be used to calculate AOT40 values:

AOT40estimate = AOT40measured ×

total possible number of hours (*)

number of measured hourly values

(*)

being the number of hours within the time period of AOT40 definition, (i.e. 08:00 to 20:00 CET from 1 May to 31 July each year, for vegetation protection and from 1 April to 30 September each year for forest protection).