The most critical pollutants, given the high concentrations in the air, continue to be tropospheric ozone (O3) during the summer months, PM10 atmospheric particulate (particle material at a size of less than 10 millionths of a meter) especially in the winter months, and nitrogen dioxide (NO2), despite the downward trend of emissions in recent years.
In 2007, 57 % of the stations registered exceedances of the daily limit value of PM10 on more than 35 days (Figure 1); the 35-day limit is often reached as early as the first half of February.
The World Health Organization (WHO) recently estimated, based on a study carried out in the years 2002-2004 in Italy’s largest cities, that more than 8 000 deaths a year can be attributed to average concentrations of PM10 greater than 20 mg/m3.
The highest levels of ozone are registered during the summer season and in areas where the impact of traffic is not direct. The long-term objective for the protection of human health (120 mg/m3) was exceeded by the vast majority of the stations: during the summer period of 2008, only 11 % of the stations did not register exceedances of the long-term objective (Figure 2).
Ozone also has negative effects on human health, though to a lesser extent than PM10. In the above mentioned study, WHO estimated that approximately 500 deaths a year can be attributed to this pollutant.
In the case of nitrogen dioxide, the annual limit value for the protection of human health (40 µg/m3), which shall enter into force in 2010, was met by 65 % of the stations in 2007 (Figure 3) (http://annuario.apat.it/capitoli/Ver_6/en/Air%20quality.pdf - Paragraph ‘Air Quality’, pg 74).
[Commonality topics] air pollution
[COMMONALITY] What are the state and impacts?