Advanced environmental chemistry 3

CHAPTER INDOOR AIR POLLUTION 3.1 Volatile Organic Compounds in Indoor Environments  Most people spend up to 80% of the day in one indoor environment or another, where pollution levels can be higher, pollutant sources are more varied and exposures are more important than those found in outdoor microenvironments  Intereting      topics: The types of VOCs commonly found in indoor air, Sources/source characteristics of indoor VOCs, Measurement techniques for profiling indoor VOCs, Health effects of VOCs, Reducing indoor VOCs VOLATILE ORGANIC COMPOUDES (VOCS) very volatile organic compounds (VVOC),  volatile organic compounds (VOCs)  semivolatile organic compounds (SVOCs)  particulate organic matter (POM) - commonly used to describe organic compounds in indoor air  Compound Boiling ranges (WHO) VVOCs °C and 50–100 °C VOCs 50–100 °C to 240–260 °C SVOCs 240–260 °C to 360–400 °C POM higher than 380 °C  Types  of Indoor VOCs Hundreds of VOCs are found in a typical nonindustrial indoor environment  aromatic hydrocarbons, alkenes, alcohols, aliphatic hydrocarbons, aldehydes, ketones, esters, glycols, glycolethers, halocarbons, cycloalkanes and terpenes  amines like nicotine,pyridine, 2-picoline, 3ethenylpyridine and myosmine in smoking microenvironments  low molecular weight carboxylic acids, siloxanes, alkenes, cycloalkenes and Freon 11 Sources of Indoor VOCs VOCs are ubiquitous in indoor environments:  consumer products, furnishing and building materials, office equipment, air fresheners, paints, paint strippers, household solvents and in microorganisms  humans and their indoor activities: cooking, cleaning, building renovation and tobacco smoking  intrusions of VOCs from outdoor traffic, biogenic and industrial emissions  indoor air reactions: reaction of ozone with 4phenylcyclohexene in carpets and with latex paints to generate aldehydes Outdoor sources: Traffic, industry (aliphatic and aromatic hydrocarbons; aldehydes; ketones; esters)  Building material: Insulation, paint, plywood, adhesives (aliphatic and aromatic hydrocarbons; alcohols; ketones; esters)  Furnishing material: Furniture, floor/wall coverings (aliphatic and aromatic hydrocarbons; alcohols; halocarbons; aldehydes; ketones; ethers; esters)  Garage and combustion appliances: Vehicle emission, tobacco smoking, candles (aliphatic and aromatic hydrocarbons; aldehydes, amines)  Consumer products: Cleaning, personal care products (aliphatic and aromatic hydrocarbons; alcohols; halocarbons; aldehydes; ketones; terpenes; ethers; esters)  Equipment: Laser printers,photocopiers, computers,other office equipment (aromatic hydrocarbons; aldehydes; ketones; esters)  Indoor activities: Cooking, tobacco smoking, use of water and solvents (amines; aliphatic and aromatic hydrocarbons; aldehydes; halocarbons)  Ventilation systems: Filters of heating, ventilation and air-conditioning systems (aliphatic and aromatic hydrocarbons; alcohols; halocarbons; aldehydes; ketones; terpenes; ethers; esters)  Biological sources:Humans, moulds, bacteria, plants (terpenes, glycoesters; alcohols; esters; aldehydes)   Comparison of Indoor-to-Outdoor Concentration Ratios    Assumes that the indoor-to-outdoor pollutant ratio depends on indoor and outdoor pollutant sources as well as the ventilation rates of the source and the sink: CI/C0 = + 1/C0 (Ssource – Ssink)/(qsource – qsink) , q : rate of ventilation, Ssink : indoor pollutant sinks, Ssource : indoor pollutant sources C: pollution concentration level Indoor-to-outdoor pollutant ratio = for a VOC : comparable indoor and outdoor sources Ratio > 1: dominantly indoor sources 10  Biomass Burning Biomass burning in indoor environments (purpose of cooking or heating): fuel wood, animal dung, crop residues, charcoal, coal (in developing countries)  Household cooking stoves and space heaters are counted in billions in the world, providing the very basic household needs of heat; however, they are a source of significant levels of pollutants, when dirty biomass fuels and inadequate technologies are used  Levels of particles, PAHs, CO, and other air pollutants found in the kitchens of developing-country villages are orders of magnitude above Western urban levels or relevant standards  The household sources emit directly into the indoor spaces and at the times of human occupancy  54  The majority of particles emitted from biomass burning are ultrafine,with only a small fraction in the larger size range, and with most of the mass present in the particles less than 2.5 μm in aerodynamic diameter (1) the particle mass distribution from wood (pine, oak, eucalyptus) combustion has a single mode at approximately 0.1–0.2 μm, (2) the particles are compact structures with fractallike dimensions close to and contained low mass fractions of volatile compounds (3) that operating conditions, such as the air supply, had astrong impact on the particle size distribution and the emission of particlebound PAHs 55       Vegetation burning: retene, phytosterols, ligmens,phenalic compounds from lignins and diterponoids from resins The emissions from wood-burning stoves were found to be acidic (pH 2.8–4.2) Organic acids: monocarboxylic (from combustion of fossil fuels and biomass) and diacarboxylic acids High concentrations of PAHs have been found in soot generated from woodburning stoves Using PAHs as source signatures in receptor modelling for residential wood combustion, guaiacol and its derivatives (e.g.4-methylguaiacol, 4-ethylguaiacol) result solely from the pyrolysis of wood lignin, are relatively stable in the atmosphere and can serve as unique tracers of wood Noticeable elemental carbon was found in wood smoke as well as measurable quantities of Na, K, Fe, Br,Cl, nitrate, sulfate and ammonium (Significant amounts of Na,Al, K, Sr,Ba,Cl, nitrate and sulfate were found in meat-charbroiling 56 emission) Compounds detected in indoor air and from building products 57 58 59 60 61 62 63 64 65 66 67 68 ... components Diisocyanate monomers have a strong irritant effect on the 30 respiratory tract, eyes, skin and mucous membranes 3. 3 SOURCES AND IMPACTS OF PESTICIDES IN INDOOR ENVIRONMENTS Epidemiological... inhibitor in water-based coating systems T4MDD degrades to 4-methyl-2-pentanone (MIBK) and 3, 5-dimethyl-1hexyne -3- ol 20  Aldehydes        Saturated and unsaturated aldehydes (chain lengths... odour-intensive natural materials (2methylbutane and 2-methyl-1 ,3- butadiene (isoprene)  Indoor area: monoterpenes (C10): a-pinene, bpinene, limonene and D3-carene , the sesquiterpenes (C15): b-caryophyllene