The recent Yom Kippur holiday brought clear air to Israel’s major cities, according to a scientific study published by the Environmental Protection Ministry.  According to the study levels of nitrogen oxides, a standard measure of air pollution, dropped dramatically with the beginning of the holiday, when driving is forbidden. 

In Tel Aviv, levels of nitrogen oxides dropped to 2-20 parts per billion during the holiday, returning to 205 parts per billion on Saturday night when the holiday ended.  In Jerusalem, the level dropped from 250 parts per billion on Friday afternoon to 2-12 parts per billion during the holiday.

According to the ministry, one of the pollutants measured, nitrogen monoxide, is a toxic air pollutant harmful to human health.  Levels of nitrogen monoxide and other oxides can rise to harmful levels during the days of the year, particularly in urban areas, ministry officials said.