PREFIX schema: <http://qweb.cs.aau.dk/airbase/schema/>
PREFIX property: <http://qweb.cs.aau.dk/airbase/property/> 
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT (count(?city) as ?ncity) WHERE {
{   { ?obs schema:SO2 ?so2 . FILTER(?so2 > 25.3)  } UNION 
	{ ?obs schema:SPM ?spm . FILTER(?spm > 32.1)  } UNION 
	{ ?obs schema:PM10 ?pm10 . FILTER(?pm10 > 12.3) }  UNION 
	{ ?obs schema:BS ?bs . FILTER(?bs > 11.2)  } UNION 
	{ ?obs schema:O3 ?o3 . FILTER(?o3 > 13.2) } UNION  
	{ ?obs schema:NO2 ?no2 . FILTER(?no2 > 30.2)  } UNION 
	{ ?obs schema:NOX ?nox . FILTER(?nox > 11.2) } UNION 
	{ ?obs schema:CO ?co . FILTER(?co > 38.5) } UNION  
	{ ?obs schema:Pb ?pb . FILTER(?pb > 98) } UNION  
	{ ?obs schema:Hg ?hg . FILTER(?hg > 78) } UNION 
	{ ?obs schema:Cd ?cd . FILTER(?cd > 46) } UNION 
	{ ?obs schema:Ni ?ni . FILTER(?ni > 56) } UNION 
	{ ?obs schema:As ?as . FILTER(?as > 56) } UNION 
	{ ?obs schema:C6H6 ?c6h6 . FILTER(?c6h6 > 90) } UNION 
	{ ?obs schema:PM2.5 ?pm25 . FILTER(?pm25 > 35) } }
	?obs schema:station ?station .
	?station schema:inCity ?city .
	?obs schema:year ?year .
   	?year property:yearNum "2011"^^xsd:integer .
    ?obs schema:sensor ?sensor .
    ?sensor property:statisticShortName "Mean"^^xsd:string . 
}