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(Click for frequent words.) 66 methyl chloroform 64 Methyl bromide 61 Vikane 61 PFCAs 59 fluorocarbons 59 organophosphate insecticides 59 sulfate aerosol 59 herbicide atrazine 59 allergenic proteins 59 ozone depleting substance 58 Carbon dioxide CO2 58 azinphos methyl 58 toxaphene 58 potent greenhouse gas 58 bioaccumulative 58 deca BDE 58 deplete ozone 57 isoprene 57 fluorotelomers 57 Deca BDE 57 carbon tetrachloride 57 nitrogen trifluoride 57 carbofuran 57 soil fumigant 57 organo phosphate 57 PFOAs 57 hydrogen sulphide H2S 57 developmental neurotoxicity 57 PAHs polycyclic aromatic hydrocarbons 57 DDVP 57 ecotoxicological 57 organophosphate insecticide 57 nanoclays 57 atrazine herbicide 57 furan 57 ozone particulate matter 57 Inert ingredients 57 carcinogenic dioxins 57 Formic acid 57 #,# dichlorobenzene 56 Carbaryl 56 fumigants 56 fluorinated chemicals 56 heptachlor 56 toxicant 56 insecticidal properties 56 halons 56 dichlorodiphenyltrichloroethane 56 airborne pollutant 56 organochlorine 56 perfluorocarbons PFCs 56 nitrogenous compounds 56 Halons 56 chlorinated hydrocarbon 56 Pyrethroids 56 monensin 56 bioaccumulation 56 Halogenated 56 suspected carcinogen 56 Paraquat 56 benzyl alcohol 56 chlorofluorocarbon CFC 56 aromatic amines 56 polyaromatic hydrocarbons 56 Chromium VI 56 ozone particulates 55 pyrethrins 55 biomagnification 55 Carbofuran 55 stratospheric ozone depletion 55 benzoates 55 Nitrogen oxide 55 pesticide aldicarb 55 virginiamycin 55 methyl parathion 55 endocrine disrupting chemicals EDCs 55 reproductive toxicity 55 ozone depleting gases 55 endocrine disrupting chemical 55 polybrominated diphenyl ether 55 carbamates 55 fungicides herbicides 55 carcinogenic compounds 55 chlorofluorocarbons CFC 55 inorganic salts 55 Greenhouse gasses 55 ammonia NH3 55 groundwater contaminant 55 Flame retardants 55 Sulfates 55 synthetic pyrethroids 55 pesticide carbofuran 55 chemical perfluorooctanoic acid PFOA 55 CFCs chlorofluorocarbons 55 Chlorine dioxide 55 COREXIT 55 bifenthrin 55 Sulphur dioxide 55 Volatile Organic Compounds 55 termiticides 55 sulfate aerosols 55 spore forming 55 pesticides 55 Methyl Bromide 55 carbamate insecticides 55 cocaine alkaloid 55 phosphonate 55 organochlorine pesticide 55 phosphine 55 sulfur trioxide 55 Elemental mercury 54 trihalomethanes THMs 54 elevated atmospheric CO2 54 tropospheric ozone 54 oxidizing agent 54 potent carcinogen 54 halogenated 54 organotin 54 Chlorpyrifos 54 bisulfite 54 naturally occuring 54 biogenic emissions 54 fluorinated gases 54 bioaerosol 54 Nitrogen oxides 54 genetically engineered organisms 54 Inorganic arsenic 54 aldicarb 54 allergenicity 54 EtO 54 Carbon tetrachloride 54 atmospheric pollutants 54 HBCD 54 CFCs HCFCs 54 methyl iodide 54 carcinogenic polycyclic aromatic hydrocarbons 54 arsenate 54 Acrylamide 54 ozone O3 54 monoterpenes 54 synthetic nitrogen fertilizers 54 resorcinol 54 eco toxicological 54 perfluorinated compounds 54 perfluorinated 54 diquat 54 nitrogenous 54 pesticide lindane 54 organophosphate 54 Volatile Organic Compounds VOCs 54 chlorinated compounds 54 anthropogenic greenhouse gas 54 Aspergillus flavus 54 gasses emitted 54 estrogen mimicking 54 N2O emissions 54 #,# DCB 54 DecaBDE 54 terpenes 54 Bt Bacillus thuringiensis 54 Sodium cyanide 54 parathion 54 Chlorofluorocarbons 54 naturally occurring bacterium 54 fumigant 54 elemental phosphorus 54 toxicants 54 decaBDE 54 CFC propellants 54 intranasal zinc 54 polybrominated 54 toxic pollutant 54 chloropicrin 54 biotransformation 54 Biodegradation 54 methylparaben 53 thermal decomposition 53 Polybrominated 53 organophosphorus pesticides 53 anthropogenic carbon dioxide 53 bacterial decomposition 53 hydrofluorocarbon HFC 53 physico chemical properties 53 Volatile Organic Compound VOC 53 nitrate fertilizers 53 diazinon malathion 53 synthetic pesticides herbicides 53 PCBs polychlorinated biphenyls 53 organophosphate pesticide 53 fipronil 53 inorganic compounds 53 TBBPA 53 cyclohexane 53 VOC Volatile Organic Compounds 53 Methylmercury 53 oxidized mercury 53 Dieldrin 53 endocrine disrupter 53 algal toxins 53 nitrogen oxides carbon monoxide 53 alachlor 53 deca BDEs 53 nanoscale particles 53 HCFC #b 53 chlorobenzene 53 anthropogenic greenhouse gases 53 phenanthrene 53 azo dyes 53 invisible odorless tasteless 53 pyrethroids 53 anthropogenic emissions 53 chlorpyrifos 53 DDT pesticide banned 53 flame retardants PBDEs 53 Allicin 53 Imidacloprid 53 diacetyl vapors 53 pesticidal 53 dimethyl sulphide 53 vinclozolin 53 reactive nitrogen 53 Polycyclic aromatic hydrocarbons 53 Methyl mercury 53 methyl bromide 53 carcinogenic pollutants 53 Ozone depleting substances 53 hydrogen peroxide H#O# 53 salinomycin 53 diisocyanate 53 synthetic musks 53 endocrine disruptor 53 Aspergillus niger 53 pollutant 53 microbial organisms 53 acaricide 53 tributyltin 53 toxic solvents 53 Dursban 53 pesticides herbicides fungicides 53 dieldrin 53 biphenyl 53 chemical ammonium perfluorooctanoate 53 herbicide glyphosate 53 nitrous oxide N2O 53 inert ingredients 53 epoxides 53 hydrochlorofluorocarbons HCFCs 53 Bt# corn 53 matrix interferences 53 gaseous ozone 53 clopyralid 53 mercury potent neurotoxin 53 estrogenic compounds 53 pesticide 53 potent carcinogens 53 harmful gasses 53 Nitric acid 53 pathogenic micro organisms 53 bromine compounds 53 hydroxyl radical 53 juglone 53 Ozone depletion 53 bacterial toxin 53 Volatile Organic Compounds VOC 53 preharvest 53 Earth ozone layer 53 flame retarding 53 lindane 53 aquatic biota 53 Organophosphate 53 acid PFOA 53 chlorofluorocarbon 53 pentaBDE 53 coccolithophores 53 Acrolein 53 bioagents 53 carbonyl sulfide 53 nematicides 53 trigger allergic reactions 53 heterotrophic 53 Carbon monoxide CO 53 clothianidin 53 rat poisons 53 termite colonies 53 glycol ether 53 bryostatin 53 formamide 53 aerosol propellants 53 synthetic insecticides 53 methyl chloride 53 insecticide sprays 53 sulfuric compounds 53 methanol formaldehyde 53 organometallic compounds 53 pyrethroid resistance 52 infectious prion proteins 52 ethyl mesilate 52 cetyl 52 Prussic acid 52 particulate matter soot 52 Acrylic acid 52 acephate 52 BHA BHT 52 Hydrogen Sulphide 52 Maillard reaction 52 toxic pesticides 52 dimethoate 52 Fumigants 52 pyrethroid 52 semicarbazide 52 marine phytoplankton 52 Calcium chloride 52 metolachlor 52 neuro toxin 52 sulphate aerosols 52 aquatic toxicity 52 Diazinon 52 microbiological contamination 52 plastics detergents 52 persistent bio accumulative 52 photosynthetic organisms 52 cancer causer 52 Sulfur compounds 52 humic 52 pyrethroid insecticides 52 cryoprotectants 52 milky spore 52 insecticidal soaps 52 carbaryl 52 benzalkonium chloride 52 phosphorous nitrogen 52 bio accumulative 52 drywall emits 52 fluorination 52 oleuropein 52 fumonisins 52 Earth biosphere 52 algal species 52 bacterial fermentation 52 SO2 emission 52 soil biota 52 Endocrine disruptors 52 LMN cream 52 pollutant particles 52 Ethylene oxide 52 Atrazine 52 nitrification 52 sterilant 52 diphacinone 52 acrolein 52 ODSs 52 nitrous oxides 52 Fipronil 52 gaseous pollutants 52 allelopathic 52 Oxybenzone 52 polynuclear aromatic hydrocarbons 52 ozone depleting chemicals 52 Polychlorinated biphenyls PCBs 52 nitrates phosphates 52 magnesium silicate 52 perfluorooctanoic acid PFOA 52 microbials 52 synthetic nitrogen fertilizer 52 naturally occurring mineral 52 sulfonic acid 52 broadleaf weed killer 52 pesticides insecticides 52 Hydrogen cyanide 52 insecticide endosulfan 52 Atmospheric CO2 52 nonylphenol 52 hydrogen sulfide ammonia 52 SOx NOx 52 DBPs 52 autotrophic 52 spinosad 52 fungus Aspergillus 52 herbicide Atrazine 52 herbicides pesticides 52 endocrine disrupting chemicals 52 chlorine atoms 52 phosphonates 52 absorbs CO2 52 hydrocarbons carbon monoxide 52 carbondioxide 52 sequestering CO2 52 Boric acid 52 bioaccumulates 52 fluorinated greenhouse gases 52 fluorochemicals 52 methyl mercury 52 fibrous mineral 52 tasteless odorless 51 atmospheric deposition 51 Limonene 51 neonicotinoid 51 cresol 51 particulate matter nitrogen oxides 51 PBDEs polybrominated diphenyl ethers 51 Vinyl chloride 51 volatilized 51 ice nucleation 51 roxarsone 51 pesticides herbicides fertilizers 51 fluridone 51 atmospheric CO2 enrichment 51 waterborne microorganisms 51 diethyl 51 toxic alkaloids 51 borane 51 microcystins 51 chlorofluorocarbons CFCs 51 butter flavorings 51 another Parkinson's triggering 51 pathogenic bacterium 51 degradability 51 glycerin byproduct 51 perfluorocarbons 51 Ozone Depleting 51 Volatile organic compounds 51 Ultrafine particles 51 dichlorodiphenyltrichloroethane DDT 51 termiticide 51 linalool 51 2 butoxyethanol 51 Dichloro Diphenyl Trichloroethane DDT 51 nitrogen 51 Diacetyl 51 Brominated 51 diuron 51 amorphous silica 51 amino acid asparagine 51 perfluorochemicals PFCs 51 specific IgE 51 pesticide atrazine 51 Chlorofluorocarbons CFCs 51 zinc sulfate 51 diazinon 51 ozone depleting compounds 51 beneficial nematodes 51 atmospheric CO2 levels 51 botulism spores 51 potassium carbonate 51 insecticides herbicides 51 harmful byproducts 51 Bt toxin 51 inorganic nitrogen 51 neonicotinoid pesticides 51 boreal ecosystems 51 tobacco budworm 51 FQPA 51 sulfur dioxide pollution 51 anammox 51 miticides 51 aluminum phosphide 51 elemental sulfur 51 nootkatone 51 chlorinated solvents 51 Bt toxins 51 Movento 51 CFCs 51 fluorinated compounds 51 dimethyl sulfide 51 Sodium bicarbonate 51 Persistent Organic Pollutants POPs 51 tributyl tin 51 thiourea 51 Chlordane 51 microbial contaminants 51 zearalenone 51 synthetic pyrethroid 51 cyanoacrylates 51 Hydrogen Sulfide H2S 51 chlorinated pesticides 51 Hydrogen sulphide 51 nitrates nitrites 51 Guthion 51 carbon dioxide concentrations 51 sodium salts 51 Fine particulates 51 Tailpipe emissions 51 Microcystis 51 adventitious presence 51 phosphorus pollution 51 ethoxylates 51 Salicylate 51 hexachlorobenzene HCB 51 Naphthalene 51 volatilize 51 bacteria Bacillus anthracis 51 Serum phosphorus 51 Ethylene glycol 51 zinc oxide nanoparticles 51 Glyphosate 51 diphenyl ethers 51 hydrofluorocarbons HFCs 51 rodenticide 51 combustion byproducts 51 phosphine gas 51 microalgal 51 DDT PCBs 51 hoofed critters 51 amphibole asbestos 51 Antarctic ozone 51 polyacrylamide 51 dioxins PCBs 51 Haber Bosch process 51 metam sodium 51 pesticide chlorpyrifos 51 particulate contamination 51 cerium oxide nanoparticles 51 Bromate 51 triclocarban 51 volatilization 51 naturally occurring amino acid 51 genotoxic substance 51 organochlorines 51 tebuthiuron 51 eucalyptol 51 Ozone Depleting Substances ODS 51 nematicide 51 nitrous oxide emission 51 brodifacoum 51 bile acid 51 toxic methylmercury 51 pyrethroid insecticide 51 antifouling coatings 51 siloxanes 51 hydro chlorofluorocarbons 51 Trichodesmium 51 Stachybotrys 51 Calcium carbonate 51 L cysteine 51 Nitrogen Oxides 51 Tetrodotoxin 51 spore forming bacteria 51 ethylmercury 51 Luesch 51 tiny single celled 51 Rotenone 51 carboxylic acid 51 microbiological contaminants 51 fucoidan 51 Nitrosamines 51 HAAs 51 potent neurotoxin 51 ozone depleting CFCs 51 chemically reactive 51 Domoic acid neurotoxin 51 hydrated lime 51 predatory mites 51 toxicity 51 Pasteuria 51 Sulfur Dioxide 51 carcinogenic byproducts 51 hypochlorous acid 51 limonene 51 tributyltin TBT 51 Sulfur Dioxide SO2 51 polycyclic aromatic 51 polycyclic aromatic hydrocarbon 51 mimics estrogen 51 Toxics Release Inventory TRI 51 miticide 51 biogenic 51 inorganic mercury 51 naturally occurring compounds 51 calcium hydroxide 51 #,# dichloroethane 51 metaldehyde 51 synthetic fertilizers pesticides 51 carcinogens mutagens 51 hydrous 51 sensitizers 51 halogenated compounds 51 spectroscopic analysis 51 xenobiotic 51 microorganism 51 Dioxane 50 ultrashort pulses 50 spectroscopic technique 50 carcinogenic chemicals 50 Biogenic 50 phosmet 50 chlorofluorocarbons 50 harmful vapors 50 Lindane 50 calcium carbonates 50 reproductive toxicant 50 estrogenic chemicals 50 mammalian toxicity 50 respiratory irritant 50 radioactive nuclides 50 hydraulic fracturing fluids 50 hydrogen sulfide H2S 50 dichloroethene 50 particulate soot 50 acute toxicity 50 biomass combustion 50 scorpion toxin 50 beryllium dust 50 Insecticidal soap 50 ozone depleting substances 50 bacterial spores 50 enzymatic pathway 50 hydroxyl radicals 50 pentachlorophenol 50 contaminant 50 graphitic carbon 50 systemic insecticides 50 Ozone depleting 50 hydrochloric acid HCl 50 #,# propanediol PDO 50 diamondback moth 50 PCBs dioxins 50 benzo pyrene 50 Methyl Tertiary Butyl Ether 50 paraquat 50 inorganic minerals 50 deltamethrin 50 PVC shower curtains 50 hydrofluorocarbon 50 gaseous byproducts 50 chemical malachite green 50 Feral swine 50 Louis Camille Maillard 50 discodermolide 50 iron sulfate 50 naturally occurring substance 50 immunotoxicity 50 chlorine disinfection 50 acetonitrile 50 glyphosate Roundup 50 naphthenic acids 50 chromium VI 50 ozone depletion 50 chemicals 50 denaturant 50 chlorine bleaching 50 geraniol 50 manmade greenhouse gas 50 chlorate 50 PPCPs 50 emit sulfur dioxide 50 decaffeination 50 acetochlor 50 formaldehyde benzene 50 biocidal 50 sulfur oxide SOx 50 filamentous fungus 50 nuclides 50 Methylene Chloride 50 biopesticides 50 insect outbreaks 50 Ionic liquids 50 hazardous solvents 50 cellulase enzymes 50 pathogenic microbes 50 Triclosan 50 organophosphorous 50 PLA polymer 50 engineers AIChE SmartBrief 50 hydrochlorofluorocarbon 50 hormone disrupter 50 carbonyls 50 atmospheric aerosols 50 insecticides fungicides 50 chlorinated solvent 50 soluble salts 50 atmospheric nitrogen 50 supercritical CO2 50 respirable 50 amygdalin 50 supercritical fluids 50 NOx nitrogen oxide 50 thymol 50 atmospheric methane 50 thirdhand smoke 50 pest repellents 50 methane CH4 50 sodium chloride salt 50 carboxylic acids 50 smog forming compounds 50 spreader sticker 50 tetrachloroethene 50 nitrogen fixation 50 fluorotelomer 50 polycarbonate plastic bottles 50 smog forming 50 Dipel 50 spoilage bacteria 50 transgenic plants 50 polyamines 50 genetically modified organism 50 tetrahydrofuran 50 chemically alters 50 bioorganic 50 Volatile Organic Compound 50 odorous compounds 50 benzopyrene 50 refrigerant leaks 50 pesticides synthetic fertilizers 50 flexible polyurethane foam 50 mirex 50 fumigant methyl bromide 50 thiosulfate 50 pre biotic 50 chlorine byproducts 50 potentially carcinogenic 50 VOCs Volatile Organic Compounds 50 diacetate 50 Spinosad 50 organophosphates 50 perfluorooctane sulfonate 50 Stachybotrys chartarum 50 stratospheric ozone 50 naturally occurring substances 50 contrast chlorine disinfection 50 Biodegradable plastics 50 particulate matter sulfur dioxide 50 deuterated 50 phosphorus runoff 50 aflatoxins 50 alkaloids 50 CFC refrigerants 50 silibinin 50 sequesters carbon 50 organotins 50 hemolymph 50 naturally occurring micro organisms 50 carbon disulfide 50 chemical 50 bacterium Listeria 50 carbon dioxide equivalent CO2e 50 dietary supplements containing ephedrine 50 ozone depleting chlorofluorocarbons 50 cyanogenic glycosides 50 #,#,# trichloroanisole 50 absorbs carbon dioxide 50 maneb 50 nonselective herbicide 50 carbendazim 50 algaecides 50 phosphorous fertilizers 50 allyl isothiocyanate 50 prussic acid 50 partial hydrogenation 50 horticultural oils 50 gelation 50 hydrocyanic acid 50 botanical insecticide 50 methylene blue 50 probable carcinogens 50 chlortetracycline 50 Asbestos fibers 50 pathogenic fungus 50 antifungal compounds 50 endophytes 50 respirable particles 50 dichlorvos 50 endrin 50 harmful residues 50 polymorphs 50 ozone depleting 50 synthetically manufactured 50 pesticide sprays 50 tomato lycopene 50 nitrification inhibitor 50 perfluorinated chemicals 50 insecticides herbicides fungicides 50 chemical reactivity 50 silicic acid 50 allergenic protein 50 oxalic acid 50 simazine 50 perfluorooctane sulfonate PFOS 50 hormone disruptor 50 alpha emitters 50 polyphenyl isocyanate 50 ammonia hydrogen sulfide 50 trichloroethane 50 CO2 CH4 50 cellulases 50 methanogenesis 50 Aflatoxins 50 organic compounds 50 naturally occurring bacteria 49 dioxin PCBs 49 cuprous oxide 49 oxidative degradation 49 thiosulphate 49 desiccants 49 equimolar 49 allergenic foods 49 monocropping 49 naturally occurring 49 photochemical reactions 49 chlorophyll molecule 49 stachybotrys 49 genetically modified organism GMO 49 leachables 49 nitrogenase 49 quinone 49 corona discharge 49 esterases 49 benzaldehyde 49 sulfur dioxide SO2 49 pollen pet dander 49 isopropyl 49 microbial biofilms 49 benzoic acid 49 hydrofluorocarbons HFCs perfluorocarbons PFCs 49 polybrominated diphenyl ether PBDE 49 nitrate nitrogen 49 dichlorobenzene 49 toxic residues 49 foliar application 49 CaCO 3 49 hydrogen cyanide HCN 49 plant sterol esters 49 sodium bromide 49 Pyrethrins 49 capsaicinoids 49 zero valent iron 49 organochlorine pesticides 49 repel pests 49 xylenes 49 amides 49 ammonium salt 49 hydroperoxide 49 carbonyl 49 monoxide 49 supercritical fluid 49 sweetener xylitol 49 brassinosteroids 49 VOC emission 49 insecticidal 49 adipic acid 49 DDT pesticide 49 suberin 49 Aminopterin 49 Cry1Ab 49 photochemistry 49 PCBs DDT 49 peroxynitrite 49 Rodenticide 49 neurotoxic 49 airborne particulate matter 49 Rubisco 49 refrigerant gases 49 Corexit #A 49 nitrification inhibitors 49 supercritical carbon dioxide 49 ultra violet radiation 49 engineered nanomaterials 49 Selectrocide 49 odor neutralizer 49 Insecticidal soaps 49 Global Warming Potential GWP 49 #,#,# trichloroethane 49 carbamate 49 silicas 49 Particulate Matter 49 potassium lactate 49 iron chelate 49 licensed applicators 49 antimycin 49 tetrachlorethylene PCE 49 Lysozyme 49 ginsenosides 49 depolymerization 49 foliar fertilizers 49 addictive nicotine 49 Mycotoxins 49 biphenyls 49 organophosphate exposure 49 organic solvents 49 tunable diode laser 49 sulfur oxides nitrogen oxides 49 condensed tannins 49 glycolipids 49 endocrine disrupting 49 naturally occurring microorganisms 49 isotope fractionation 49 degreasing agent 49 aerosols 49 organo 49 organophosphate pesticides 49 Temik 49 HFO #yf 49 Nitrogen dioxide 49 chlorinated Tris 49 acidity pH 49 photocatalysis 49 preemergence herbicides 49 ammonium chloride 49 ozone 49 Particulate emissions 49 soy protein isolates 49 silica particles 49 nanosilver 49 isosorbide 49 Hydrogen Sulfide 49 Excess nitrogen 49 piperonyl butoxide 49 unconventional superconductivity 49 nonylphenol ethoxylates 49 sodium sulfide 49 magnesium carbonate 49 curium 49 polyphosphates 49 MBTE 49 Trihalomethanes 49 chlorine atom 49 toxic flame retardants 49 Genetically engineered crops 49 thiols 49 MRLs 49 BTEX 49 Isoprene 49 kanamycin 49 nitrosamines 49 mold dust mites 49 oxalates 49 ultraviolet UV light 49 contain oxalic acid 49 TiO2 nanoparticles 49 biogeochemical cycle 49 Malathion 49 Carbon Dioxide CO2 49 chlorinated hydrocarbons 49 herbicide tolerant crops 49 sorption 49 reproductive toxicants 49 inorganic substances 49 unapproved genetically modified 49 detergents solvents 49 Cockroach allergens 49 trichloroethene TCE 49 iodomethane 49 cyanate 49 chloroprene 49 hydrolyzing 49 RfD 49 rosemary extracts 49 antimicrobial properties 49 herbicides insecticides fungicides 49 noxious chemicals 49 AquAdvantage Salmon 49 organic manures 49 disinfection byproducts 49 ethinylestradiol 49 triazine herbicides 49 Photosynthetic 49 outgas 49 trimethylamine 49 VOC volatile 49 Microcystis aeruginosa 49 physico chemical 49 carbonate minerals 49 atmospheric CO2 concentrations 49 Airplanes sprayed 49 Nitrate contamination 49 Cladosporium 49 Hydrochloric 49 anerobic 49 heterocyclic amines 49 Anabaena 49 chemical syntheses 49 benzenes 49 penta BDE 49 chemicals diazinon malathion 49 octa BDE 49 carcinogenic chemical 49 pesticide endosulfan 49 Campylobacter bacteria 49 Glutamic Acid 49 photocatalyst 49 antibiotic residues 49 saponin 49 sodium bisulfite 49 Zeolites 49 aquatic herbicides 49 toxin 49 photochemical smog 49 humic acids 49 Benzo pyrene 49 particle morphology 49 polyester resins alkyd resins 49 selenomethionine 49 rodenticides 49 nanobacteria 49 Nitrogen NOx 49 nitrogen oxides emitted 49 cyclization 49 orthophosphate 49 fracing fluids 49 emulsifying agent