PERCIVAL POTTS AND THE CLIMBING BOYS l Potts first recognised occupational cancer through exposure to coal tars (1775)… l Scrotal and nasal cancers among chimney sweeps l PAH The Water-Babies, Charles Kingsley (1862-1863)
BaP BaP l BENZO(a)PYRENE the ultimate carcinogen! l Importance of bay region
REGULATING CARCINOGENS l No thresholds l BaP as an indicator l Risk assessment l Risk 1.5x10 -5 per ng(BaP) m -3 (MOE 1997) l What is an acceptable risk? l UK PAH [B(a)P] at 0.25 ng m -3 Annual mean by 31/12/10
OTHER POLLUTANTS l HCHO – suspect carcinogen but typically unregulated in outdoor environment interior concern via furnishing regulations l PAN –some suspicions about carcinogenicity, but irritant l BENZENE – carcinogen and regulated in EC, UK 5 µg m -3 (Ann. Mean)
CARBON MONOXIDE AT ALTITUDE l Some 480 accidental deaths and 2000 suicides per year in the US l Gas or charcoal barbeque indoors l Poorly ventilated interiors especially cooking fumes on climbing or polar expeditions l Denver, Colorado high CO - high altitude means incomplete combustion of gasoline in motor vehicles, but fuel wood also a significant source
CARBON MONOXIDE IN SUBMARINES l Carbon monoxide levels in. submarines: closed space smoking among crew and equipment l Catalytically converted to CO 2 l Smokers have heightened susceptibility
l Physical symptoms headache Nausea dizziness vomiting l Cognitive Impairments attention problems multi-tasking problems poor time judgement l 50 ppm (8 hr) show some symptoms l 100 ppm (a few hours) flu-like symptoms l 150-300 ppm dizziness, drowsiness and vomiting l >400 ppm unconsciousness, brain damage and death. CARBON MONOXIDE EFFECTS Tissue hypoxia and oxidative stress…
CARBOXYHEMOGLOBIN (HbCO) l CO binds with hemoglobin at 200- 300 times the affinity of oxygen CO + HbO 2 O 2 + HbCO l Effects during exercise >2.5-4.0% l Smokers as high as 10%, l Ambient CO of 100 ppm produces 16% l Tent with a kerosene camping stove 21.5% l Half-life 3-4 hours. l HbCO – aim at <2.5% for non-smokers - time and concentration dependent 10ppm (10hours) 25ppm (1 hour) 50ppm (30 min) http://www.andyrak.com/digital01/hemoglobin.htm
BRONCHIAL TRACT CILIARY ELEVATOR l Synergistic impact of SO 2 and smoke Bronchial epithelial cells Mucous thicker outside Cilia
SULFUR DIOXIDE l Despite great improvements still considerable impact on urban epidemiology l Affect on airway function especially among people with pre-existing complaints l Hospital admissions about 2% up for a 50 µgm -3 increase – not especially large l Mortality about 3% up for a 50 µgm -3, but… l …death bought forward by a days
SULFUR DIOXIDE l Short term exposure 10-15 minutes l 266 µgm -3 (15 min) 35 exceedences per year (UK) l 350 µgm -3 (1 hour) 9 exceedences per year (NZ)
NITROGEN DIOXIDE Very widespread exposure… in urban areas… Long understanding of indoor exposure especially from gas cooking – wheeze among children NASAs Aura satellite 15 July 2006
NITROGEN DIOXIDE l Exposure above 2000 µgm -3 required to show bronchial response l Asthmatics not too different l …, but at 800 µgm -3 may sensitize to other allergens l Little confidence on mechanisms or relevant day-to-day effects, but relevance may be the chronic impact. l 200 µgm -3 (1 hour) 9 times per year (NZ)
OZONE http://www.cerc.co.uk/YourAir/index.asp Problem of heterogeneity…
Trees grow better in NY! Nature JWGregg et al 424, p183 10 July 2003
OZONE EFFECTS l Pulmonary system primary target l Biochemical effect from oxidation or peroxidation of biomolecules l Ozone-caused lung damage resembles sunburn l Reduces lung function or aggravates existing respiratory conditions such as asthma, emphysema or bronchitis l May cause chest pain, coughing, throat irritation or congestion Healthy Inflamed http://www.sbcapcd.org/sbc/ozonehealth.htm
OZONE l Background 40-70 µg m -3 l Summer 120-150 µg m -3 l 240 µg m -3 exercising – detriments to lung function l Recommendations close to background l 120 µg m -3 (8-hour) WHO l NZ Ozone (1-hour) 150 µg m -3
HUMAN HAIR OZONE REACTION l Secondary products Geranyl acetone »trans-2,6-dimethyl-2,6-undecadien-2-one6-methyl-5-hepten-2-one Decanal Pandrangi and Morrison (2008)
LEAD l Exposure to lead linked to criminal behaviour Jun 16, 2008: US study finds higher blood lead levels correlated to more arrests.
1,3-BUTADIENE l Some concern in 96/62/EC but never adopted l UK, NZ(?) have set standards l Standards will probably be met Carcinogen
FLUORIDE l Some concern in 96/62/EC but never adopted l Brick making, aluminium production and coal combustion (big source in China) l Indoor contamination of surfaces l In New Zealand largely ecological worries Aluminium smelting
SULFIDES l Hydrogen sulfide from catalytic converters - shifting the oxidation state of sulfur emissions l Regulation based on odour thresholds (7 g m -3 ) l Mercaptans - pulp mills 0.5 ppm (Manitoba) l Thiophenes and benzothiophenes from tyres, combustion etc Odour and carcinogenicity problems...
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