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Table 4 Indoor air quality in select photocopier centers in Coimbatore

From: Chronic exposure to emissions from photocopiers in copy shops causes oxidative stress and systematic inflammation among photocopier operators in India

Air quality parameters Background levels (n = 5) Mean levels (n = 5) Indoor air quality Reference levels (NAAQS, 2009)
Carbon monoxide (CO) (mg/m3) <1.2 <1.2 <1.2 2.0
Nitrogen dioxide (NO2) (μg/m3) 8.0 ± 2.6 8.4 ± 3.8 9.1 80
Ozone (O3) (μg/m3) <9.8 <9.8 <9.8 100
Fine particulate matter (PM2.5) (μg/m3) 128.1 ± 21.4 168.2 ± 34.6 78.5 60
Particulate matter (PM10) (μg/m3) 241.7 ± 44.2 376.4 ± 63.8 106.7 100
Sulphur dioxide (SO2) (μg/m3) 3.5 ± 1.5 4.7 ± 2.3 5.1 80
Lead (Pb) (μg/m3) <0.1 <0.1 <0.1 1.0
Arsenic (As) (ng/m3) <0.1 <0.1 <0.1 6.0
Nickel (Ni) (ng/m3) <0.1 <0.1 <0.1 20
Ammonia (NH3) (μg/m3) 2.3 2.5 2.7 400
Benzene (C6H6) (μg/m3) <1.0 <1.0 <1.0 5.0
Benzo(a)pyrene (BaP) (ng/m3) <1.0 <1.0 <1.0 1.0
  1. NAAQS National Ambient Air Quality Standards, 2009.
  2. Mg Milligram, μg Microgram, ng nanogram.