evidence: Large particulate pollution (PM10) and nitrogen dioxide (NO2) levels went down the most with "significant improvements" in Europe’s air quality following their decline. [...] Particulate pollution (PM2.5 and PM10) levels were highest in northern Italy and eastern Europe. Northern Italy, along with some areas of western Europe, such as in the south of the United Kingdom, Belgium and the Netherlands, also had high levels of NO2. The most significant reductions in PM2.5 and PM10 levels were found in central Europe while for NO2 they were found in urban areas of western Europe.