def days_max_gt_std(data, std):
    """
    Find the number of days where the maximum daily measurement is
    above the standard used by the EPA
    
    Inputs
    ------
        :param data: dataframe or Series with timestamp index and pollution data column.
                    should already be resampled to appropriate timebase
        :type data: pd.DataFrame or pd.Series
        :param std: standard value used by EPA
        :type std: float
    
    Returns
    -------
        count: the number of days where the max value surpassed the standard
    """
    
    daily_max = data.groupby(data.index.floor('d')).max()
    
    count = daily_max[daily_max > std].count()
    
    return count