Related by context. All words. (Click for frequent words.) 70 fine particle pollution 68 particulate pollution 66 ozone pollution 64 fine particulate pollution 63 air pollution 61 Particle pollution 61 PM#.# 60 fine particulate matter 60 particulate matter 59 fine particulates 58 ozone smog 58 soot pollution 57 particulates 56 microscopic soot 55 air toxics 55 smog 55 ozone 54 Particulate matter 53 PM#s 53 pollutants 51 pollutant ozone 51 nonattainment areas 51 soot particles 51 fine particulate 51 nitrogen dioxide 51 ozone concentrations 50 PM# [003] 50 Particulate pollution 50 pollution 50 soot 50 nonattainment 50 smoggiest 50 pollutant 50 particulate 50 diesel particulate matter 49 airborne particulate matter 49 Air Pollution 49 exceedances 49 #,# butadiene 49 smog forming 48 airborne soot 48 Fine particle pollution 48 coarse particulate matter 48 diesel exhaust 48 diesel particulates 48 Particle Pollution 48 pollutants emitted 48 carbon monoxide nitrogen dioxide 48 Diesel exhaust 48 THMs 48 particle concentrations 47 ozone nonattainment 47 Sulfur dioxide emissions 47 Fine particulate 47 SO2 emissions 47 Air Quality 47 nitrogen oxide 47 airborne particulates 47 mercury pollution 47 Toxic Release Inventory 47 smog forming pollution 47 Smog 47 sulfur dioxide emissions 47 gaseous pollutants 47 ozone particulate matter 47 particulate matter emissions 47 mercury emissions 47 nitrous oxides 46 inhalable particles 46 Nitrogen oxides 46 airborne pollutants 46 aggravates respiratory 46 sulfur dioxide nitrogen dioxide 46 pollutant emissions 46 indoor radon 46 smog forming pollutants 46 sulfur dioxide 46 sooty particles 46 asthma sufferers 46 microcystin 46 ultrafine particles 45 sulfur dioxide pollutant 45 nitrogen oxide emissions 45 hydrocarbons carbon monoxide 45 carbon monoxide hydrocarbons 45 airborne pollutant 45 Sensitive Groups 45 particulate matter PM# 45 exceedences 45 ug/m3 45 tiny soot particles 45 pollutant particles 45 smog forming emissions 45 PM# particulate matter 45 PAHs 45 PM# particles 45 respiratory illnesses 45 smoggy 45 Particulates 45 nitrogen oxide NOx emissions 45 Nitrogen dioxide 45 Nonattainment 44 diesel particulate emissions 44 elevated radon 44 carcinogen 44 tetrachloroethene 44 nitrogen oxides 44 haloacetic acids 44 particulate matter PM 44 Soil moisture 44 Liberty Clairton 44 Fine particulate matter 44 pesticide exposures 44 radon concentrations 44 carbon monoxide sulfur dioxide 44 respirable suspended particulate matter 44 sulfur dioxide emission 44 airborne particles 44 Sulfur dioxide 44 secondhand smoke 44 asthma 43 ozone pollutant 43 toxic pollutants 43 Ambient Air 43 nitrogen dioxide NO2 43 trihalomethanes 43 Secondhand smoke exposure 43 #,# DCB 43 naturally occurring fluoride 43 Pollutants 43 Fecal coliform 43 smog forming nitrogen oxides 43 Houston Galveston Brazoria 43 secondhand smoke exposure 43 particle soot 43 nitrogen oxide pollution 43 nonattainment designation 43 respirable particles 43 mercury emitted 43 lung disease 43 Air Pollutant 43 emissions 43 pollutants sulfur dioxide 43 carbon monoxide particulate matter 43 lung diseases 43 radon 43 nitrogen oxides emitted 42 aggravates asthma 42 organophosphate pesticides 42 carbon monoxide 42 chloride concentrations 42 Peanut allergies 42 μg/m3 42 particulate concentrations 42 pollen counts 42 Bq/m3 42 fecal coliform bacteria 42 mercury vapors 42 NOX emissions 42 sulfur dioxide nitrogen 42 polycyclic aromatic hydrocarbons 42 asthma chronic bronchitis 42 Lung Association 42 sulfur dioxide SO2 42 heavily polluted 42 aggravate asthma 42 Carbon monoxide CO 42 hexavalent chromium 42 AIRNow 42 EnviroFlash 42 pCi L 42 particulate emissions 42 Breathing ozone 42 carbon tetrachloride 42 irritate lungs 42 unhealthful 42 toxic pollutant 42 Asthma 42 Schkolnick 42 Gauderman 42 airborne toxins 42 topsoil moisture supplies 42 PAH concentrations 42 ammonium perfluorooctanoate 42 NOx 42 Air Pollution Control 42 Nitrogen oxide 41 NO2 41 respiratory illness 41 particulate pollutants 41 ozone precursors 41 polluted 41 smog advisories 41 pCi l 41 chlorine byproducts 41 soot smog 41 beachwater samples 41 PM#.# particles 41 airsheds 41 respiratory irritant 41 toxic chemicals 41 invasive meningococcal disease 41 cockroach allergens 41 beachwater quality 41 PBDE chemicals 41 algae blooms 41 AB# mandates 41 tropospheric ozone 41 silica dust 41 mercury 41 sootiest 41 Sulfur Dioxide 41 airshed 41 enterococcus 41 particulate soot 41 Shawn Ferreria 41 algal toxins 41 Algae blooms 41 NOx emissions 41 fluorosis 41 nitrogen oxide emission 41 Clean Air 41 Volatile Organic Compounds 41 ozone nitrogen dioxide 41 fecal bacteria 41 microscopic soot particles 41 Tailpipe emissions 41 Carbon monoxide 41 mercury sulfur dioxide 41 lung ailments 41 exertion outdoors 41 polluted waterways 41 Carbon dioxide emissions 40 bioaccumulative 40 foothills bordered 40 noxious pollutants 40 nitrogen dioxide carbon monoxide 40 HAAs 40 coarse particles 40 formaldehyde carcinogen 40 Urbaszewski 40 topsoil moisture 40 NAAQS 40 National Weather Service 40 trihalomethane 40 spokeswoman Tressa Tillman 40 enterococcus bacteria 40 bronchitis asthma 40 ashfall 40 carbolic acid particles 40 PBDEs 40 carcinogen benzene 40 whooping cough 40 Localized flooding 40 total dissolved solids 40 sewer overflows 40 Ozone Alert 40 microcystins 40 Soil moisture levels 40 ozone precursor 40 methyl mercury 40 ozone particulates 40 dischargers 40 nitrate contamination 40 sulfur dioxide pollution 40 Sulphur dioxide 40 micrograms 40 cockroach allergen 40 microcystis 40 algal blooms 40 organophosphate exposure 40 sewage overflows 40 Microcystis 40 smoggiest regions 40 untreated tooth decay 40 exceedance 40 greenhouse gases 40 volatile organic compounds 40 trichlorethylene 40 Particulate Matter PM 40 Fine particulates 40 asthma emphysema 40 ash 40 SO2 sulfur dioxide 40 prolonged exertion 40 fecal coliforms 40 Topsoil moisture 40 chlordane 40 nutrient pollution 40 SO2 40 inhalant abuse 40 disinfection byproducts 40 Stephen Konarik meteorologist 40 coughing shortness 40 lead cadmium arsenic 40 PM#.# NAAQS 40 Air Toxics Assessment 40 photochemical smog 40 benzene carcinogen 40 smog forming gases 40 RSPM 40 μg m 40 smog soot 40 Enterococcus bacteria 40 chlorpyrifos 39 PFOS 39 asthma bronchitis 39 particulate matter SPM 39 Liaohe River 39 bronchiolitis 39 recurrent wheezing 39 rainfall 39 degrease metal parts 39 Nitrogen oxide emissions 39 weed pollen 39 fecal coliform 39 greenhouse emissions 39 Particulate 39 waterborne infectious diseases 39 PCBs dioxins 39 toxicants 39 enterococci bacteria 39 Particulate Matter 39 pedestrian fatalities 39 greenhouse gases GHG 39 Fecal bacteria 39 mercury potent neurotoxin 39 smoggiest cities 39 particulate matter emitted 39 coughing wheezing 39 BLLs 39 tailpipe exhaust 39 pCi L. 39 lung irritant 39 haloacetic acid 39 respiratory irritants 39 PennEnvironment 39 dioxins 39 creosote buildup 39 tailpipe pollutants 39 sulfur dioxide SO2 nitrogen 39 Daily Load TMDL 39 TTHMs 39 Peanut allergy 39 toxic algae 39 persistent wheezing 39 Whooping cough 39 mercury contamination 39 Secondhand smoke 39 greenhouse gas emissions 39 groundwater contaminant 39 smokestack emissions 39 radioactive isotope iodine 39 ragweed pollen 39 iodine intake 39 ammonia nitrogen 39 trichloroethene 39 polluted runoff 39 respiratory diseases 39 perfluorooctane sulfonate 39 diesel particulate 39 ozone attainment 39 AQHI 39 crystalline silica dust 39 cough wheeze 39 sulfur dioxide carbon monoxide 39 lung irritants 39 SO2 emission 39 smog forming nitrogen oxide 39 Quality Standards NAAQS 39 diesel fumes 39 phosphorus 39 secondhand tobacco 39 phosphorus pollution 39 nonpoint source pollution 39 PFOAs 39 carbon dioxide emissions 39 tetrachlorethylene 39 Knozone 39 e coli bacteria 39 indoor dampness 39 dental decay 38 carbon disulfide 38 ghg emissions 38 precipitation 38 beryllium dust 38 expectorated matter 38 nitrogen oxides carbon monoxide 38 snowfall accumulations 38 exceedence 38 UV radiation 38 Fargo ND Wahpeton ND 38 harmful vapors 38 marine biotoxin 38 carbon monoxide nitrogen oxides 38 soot particulates 38 particles PM#.# 38 measurable snowfall 38 nitrogen deposition 38 lung infections 38 gum disease 38 Blowing dust 38 Nitrogen Oxide 38 outdoor exertion 38 naturally occurring arsenic 38 blistering sunburns 38 Methylmercury 38 airborne allergens 38 diazinon 38 crystalline silica 38 smokiest 38 Janice Nolen 38 Rapid Transit ridership 38 nitrogen oxide sulfur dioxide 38 turbidity 38 mercury polluter 38 PFOA 38 suspected carcinogen 38 Hydrogen sulfide 38 pollen 38 Pollution 38 Dimitri Stanich spokesman 38 erionite 38 trichloroethane 38 nitrogen oxides NOx 38 coarse particulates 38 pertussis 38 μg m 3 38 nutrient discharges 38 Seilback 38 asthma hay fever 38 vapor intrusion 38 Peter Iwanowicz 38 TTHM 38 designated nonattainment 38 allergens 38 Weather Service 38 asthma flare ups 38 CO poisonings 38 smog forming chemicals 38 toxaphene 38 Keetch Byram Drought 38 particulate opacity mercury 38 dissolved oxygen levels 38 AQMD 38 emission 38 mold spores 38 airway constriction 38 emphysema 38 Relative humidity 38 naturally occurring asbestos 38 nitrogen discharges 38 mosquito borne virus 38 PDBEs 38 emission reductions 38 faecal contamination 38 GHG pollution 38 Norlite 38 Passive smoking 38 nitrogen oxides NOx emissions 38 Ozone Action 38 carcinogenic polycyclic aromatic hydrocarbons 38 tobacco specific nitrosamines 38 particulate traps 38 Norovirus infection 38 mold spore counts 38 disinfectant byproducts 38 harmful pollutants 38 ultraviolet radiation 38 lindane 38 Particulate emissions 38 mcg dl 38 Toxics Release Inventory 38 raw sewage overflows 38 aggravate respiratory 38 pollutant discharges 38 smog acid 38 Morgan Quitno Press 38 acrolein 38 nitrogen oxide NOx 38 odorless colorless gas 38 emit pollutants 37 E. coli bacteria 37 dioxin 37 particulate matter soot 37 nitrous oxide N2O 37 cotinine levels 37 respirable suspended particulates 37 droplet nuclei 37 abnormally dry 37 pollutant loadings 37 EPA Toxics Release 37 GHG emission 37 unintentional poisoning 37 Cockroach allergens 37 measurable precipitation 37 radioiodine 37 polybrominated diphenyl ethers PBDEs 37 sewage spills 37 VOC emissions 37 tritium concentrations 37 tailpipe gases 37 Smog Alert 37 Methyl mercury 37 fumigants 37 lung cancer 37 diarrheal illness 37 phthalate metabolites 37 Drought Monitor map 37 atmospheric pollutants 37 perchlorethylene 37 remote blackwater streams 37 Kids Count 37 mercury concentrations 37 carcinogen NNK 37 Air Toxics 37 groundwater contamination 37 carcinogens 37 driest 37 Cow burps 37 load TMDL 37 Myron Padgett 37 heat trapping gases 37 Elaine Makatura spokeswoman 37 respiratory ailments 37 parasite cryptosporidium 37 nitrate concentrations 37 prenatal exposures 37 Sadredin 37 stormwater pollution 37 atmospheric ozone 37 serum vitamin D 37 nitrobenzene 37 temperature inversions 37 bio accumulative 37 legionella bacteria 37 perfluorochemicals 37 NOX SOX 37 noxious gases 37 gases emitted 37 total coliforms 37 mercury vapor 37 smoggy skies 37 heat trapping carbon dioxide 37 Environmental Protection Agency 37 spontaneously ignite 37 toxins 37 circulatory diseases 37 emmissions 37 nitrogen oxides particulate matter 37 airborne contaminants 37 heart disease 37 chemical ammonium perfluorooctanoate 37 Rainfall totals 37 VOCs 37 nonroad diesel engines 37 algal toxin 37 sulfur dioxide nitrogen oxide 37 methylmercury 37 Soot 37 dioxin PCBs 37 coli bacteria 37 harmful chemicals 37 toxin 37 Rubbertown 37 Adenoviruses usually cause 37 respiratory irritation 37 dust mite allergen 37 bark beetle infestations 37 pesticide poisonings 37 unintentional poisonings 37 Precipitation totals 37 pollutions 37 chronic lung 37 rainfall totals 37 carbondioxide emissions 37 Allergic rhinitis 37 cotinine 37 Vibrio infections 37 greenhouse gas emission 37 Sewer overflows 37 c reactive protein 37 trivalent chromium 37 flash flooding 37 chemical flame retardants 37 passive smoking 37 Emissions 37 trichloramine 37 chemical vapors 37 polychlorinated biphenyls 37 wastewater discharges 37 Excessive Heat 37 sulfur oxides 37 McAllen Edinburg Mission 37 reproductive toxicants 37 sulfur dioxide SO2 emissions 37 sanitary sewer overflows 37 Bladder cancer 37 harmful algal blooms 37 E. coli 37 particulate emission 37 Chronic insomnia 37 Carbon Monoxide CO 37 hydrogen sulfide ammonia 37 Severe thunderstorm watches 37 particulate matter nitrogen oxides 37 sewage discharges 37 heat trapping gases emitted 37 coliform 36 surplus topsoil moisture 36 TMDLs 36 sulfur trioxide 36 PBDE 36 blackwater streams 36 lung scarring 36 indoor allergens 36 radioactive Iodine 36 harmful contaminants 36 turbidity cloudiness 36 Domoic acid 36 bronchial asthma 36 harmful tailpipe emissions 36 Nitrogen Dioxide 36 PBDEs polybrominated diphenyl ethers 36 particulate matter sulfur dioxide 36 aflatoxins 36 Drought Monitor 36 Forage availability 36 phosphorous 36 nitrate 36 cow enteric 36 nitrous oxide emissions 36 contaminants 36 ingested accumulates 36 allergens irritants 36 sulfur hexafluoride 36 lung function 36 aerosol particles 36 Pollutant 36 rems 36 Air Pollutants 36 toxic algal blooms 36 Coliform bacteria 36 dissolved solids 36 perfluorinated chemicals 36 spokeswoman Phillippa Cannon 36 #OHD levels 36 heaviest downpour 36 Stomach cancer 36 Elevated arsenic 36 Asbestos fibers 36 dioxins furans 36 relative humidities 36 pollutant discharge 36 Fecal coliform bacteria 36 organochlorine pesticides 36 tremolite asbestos 36 juglone 36 vinyl chloride 36 chlorine residuals 36 COPD 36 sewage sludge incinerators 36 foothill communities 36 Toxics Release Inventory TRI 36 neurotoxin 36 Keith Overcash 36 coliform bacteria 36 microgram 36 shigellosis 36 nitrous oxide emission 36 infants Sundlof 36 Ozone disinfection produces 36 barium cadmium 36 polychlorinated biphenyl 36 nitrogen dioxide emissions 36 Toxic Release 36 meningococcal disease 36 pine pollen 36 venomous snake bites 36 tailpipe emissions 36 Non Ionising Radiation 36 dust mite allergens 36 colorless odorless poisonous 36 Greenhouse Gas Inventory 36 carbon dioxide sulfur dioxide 36 TMDL 36 Disease Registry ATSDR 36 colorless odorless radioactive 36 arsenic mercury 36 Polluted runoff 36 lung irritation 36 spokeswoman Cathy Milbourn 36 Emily Figdor 36 phosphorus concentrations 36 greenhouse gas 36 Tooth decay 36 nonseasonally adjusted unemployment 36 benzo pyrene 36 Oesophageal cancer 36 flulike illnesses 36 Clean Indoor 36 Enterococci 36 algal bloom 36 temperature inversion 36 Dechlorane Plus 36 flame retardant chemicals 36 Emissions Vehicle AT PZEV 36 carcinogenic compounds 36 Karen Schkolnick spokeswoman 36 UVA rays 36 perchlorate contamination 36 reducing visibilities 36 Doe Run smelter 36 spokeswoman Davina Marraccini 36 radioactive iodine 36 lung cancer mesothelioma 36 Nitrogen Oxides 36 Beach Bummers 36 relative humidity 36 airborne asbestos fibers 36 sun ultraviolet radiation 36 peat bog fires 36 anthropogenic greenhouse gas 36 Karen Schkolnick 36 mold spore count 36 toxic flame retardants 36 TCE vapors 36 chronic respiratory 36 particulate matter carbon monoxide 36 concentrations 36 infected mosquitoes 36 Superfund sites 36 driest summers 36 atopy 36 Dioxane 36 total coliform 36 phosphorus runoff 36 Sulfur compounds 36 preventable hospitalizations 36 emphysema chronic bronchitis 36 sulfur dioxide nitrous oxide 36 exhaled nitric oxide 36 bacteria enterococci 36 wood stoves 36 oVOCs 36 wastewater discharge 36 unburned hydrocarbons carbon monoxide 36 combustion byproducts 36 asbestos fibers 36 Obstructive sleep apnea 36 hemolytic uremic syndrome 36 gastrointestinal illnesses 36 Carbon dioxide emission 36 sulfur dioxide particulates 36 carcinogenic chemicals 36 carbaryl 36 Repeated concussions 36 preterm births 36 Max Temp 36 exhaust emissions 36 benzene toluene xylene 36 nonpoint source 36 algae bloom 36 carbon dioxide CO2 emissions 36 trichlorethylene TCE 36 sulfuric dioxide 36 untreated sewage 36 pesticide residue 36 Ozone 36 Bob Kard 36 PANHANDLE Temperatures 36 RfD 35 chronic respiratory illnesses 35 woodsmoke 35 sinus infections 35 effluent discharged 35 buttery flavoring 35 Elevated mercury 35 rotten egg odor 35 floods heatwaves droughts 35 Acrolein 35 Pet dander 35 mercury PCBs 35 burnoffs 35 hottest driest 35 millirem 35 Elemental mercury 35 nitrogen trifluoride 35 PAH compounds 35 woodstoves 35 CO poisoning 35 metal degreasing 35 PCBs polychlorinated biphenyls 35 Angus Barkhuff 35 diarrheal illnesses 35 polychlorinated biphenyls PCBs 35 Chromium VI 35 untreated sleep disordered 35 bacteriological contamination 35 GHGs 35 ergocalciferol 35 respirable suspended 35 Reye syndrome rare 35 Wind Advisories 35 abrasive volcanic ash 35 birthweights 35 particles emitted 35 chlorinated pesticides 35 volcanic smog 35 emission reduction 35 bronchopulmonary dysplasia 35 #,# dichloroethane 35 Tobacco Smoke 35 toxicity 35 chromium 35 coarse particulate 35 Vitamin D deficiency 35 Superfund hazardous waste 35 airborne mold spores 35 uncontrolled hazardous waste 35 Dioxins 35 spokeswoman Skylar McElhaney 35 benzene 35 low humidities 35 chemical perfluorooctanoic acid PFOA 35 West Nile encephalitis 35 cryptosporidium 35 smog forming ozone 35 fluorinated gases 35 combustible dust 35 GhG emissions 35 pollutant emission 35 coldest temperature 35 smokestack pollutants 35 hydrogen sulfide 35 Measurable precipitation 35 respiratory infections 35 PCB contamination 35 nitrous acid 35 respirable particulate matter 35 polluter 35 permanently discontinue Vectibix 35 Domoic acid neurotoxin 35 Huaihe 35 snowfall accumulation 35 nonroad diesel 35 abusing inhalants 35 plasma urate 35 heavier rainfalls 35 preventable illnesses 35 springtime allergies 35 Isolated thunderstorms 35 Air fresheners 35 carbon dioxide CO2 emission 35 piperonyl butoxide 35 tiny airborne particles 35 organochlorine compounds 35 nitrous oxide NOx 35 carbon monoxide poisonings 35 cTnT levels 35 harmful gases 35 carcinogenic benzene 35 ultra violet radiation 35 Fasting glucose levels 35 organochlorines 35 respirable 35 Carbon monoxide poisoning 35 solvent vapors 35 Algal blooms 35 secondhand smoke SHS 35 spokeswoman Heidi Griesmer 35 Rainfall 35 hydrological drought 35 g/m3 35 smog forming compounds 35 potent carcinogen 35 carbon monoxide CO 35 dust mites 35 Diarmid Campbell Lendrum 35 fluoride 35 cigarette smoke 35 asthmatics 35 sulfur oxide SOx 35 methyl cyanide 35 greenhouse gas nitrous oxide 35 Salmonella infections 35 phosgene 35 Freshwater mussels 35 NPRI 35 aerosol concentrations 35 Superfund cleanup sites 35 perfluoroalkyl acids 35 perfluorocarbons 35 Dioxin 35 inorganic mercury 35 arsenic benzene 35 crocidolite 35 carbon dioxide concentrations 35 spokeswoman Tisha Petteway 35 TSNAs 35 biomass combustion 35 pollens 35 mcg dL 35 PAHs polycyclic aromatic hydrocarbons 35 PAH 35 allergic reactions 35 Greenhouse Gas GHG emissions 35 Ultrafine particles 35 greenhouse gasses 35 heavy rainfall 35 acute bronchitis 35 respiratory symptoms 35 Malignant melanoma 35 EPA 35 Min Temp #.# 35 Childhood obesity 35 carcinogens benzene 35 oxide sulfur hexafluoride 35 Brian Urbaszewski 35 Polycyclic aromatic hydrocarbons 35 Taihu Lake 35 groundwater 35 smokestack scrubbers 35 Yangtze rivers 35 popcorn flavoring 35 dust pet dander 35 Superfund cleanup 35 dietary sodium 35 pollutant concentrations 35 Hydrogen Sulfide H2S 35 sulfur compounds 35 hydrocarbon vapors 35 asthma emphysema bronchitis 35 cardio vascular disease 35 nitrates 35 urine albumin 35 arsenic 35 perchlorate 35 pharyngeal cancer 35 Noro virus 35 thirdhand smoke 35 croup 35 diarrheal disease 35 acid rain 35 hydrogen chloride 35 coarser particulate matter 35 Accumulating snow 35 shigella 35 trihalomethanes THMs 35 stachybotrys 35 biotoxin 35 lowland flooding 35 unadjusted unemployment 35 stormwater runoff 35 exhaust fumes 35 trichloroethene TCE 35 Volatile Organic Compounds VOC 35 Morgan Quitno 35 deca BDE 35 poisonous carbon monoxide 35 polluters 35 trans fat intake 35 noxious gasses 35 nutrient loading 35 drywall Brincku 35 Pigeon droppings 35 respirable coal 35 Nielsen Gammon 35 mg/m3 35 frost advisories 35 poisonous fumes 35 NOx nitrogen oxides 35 bedbug outbreaks 35 chlamydia infection 35 Bacterial meningitis 35 calcium sulfate component 35 radon induced 35 RSV infections 35 meningo encephalitis 35 UV exposure 35 naturally occurring algae 34 streamflow 34 pico curies 34 sumithrin 34 pesticide drift 34 greenhouse gas emitter 34 oxalates 34 Inventory TRI 34 asthma eczema 34 RSV infection 34 harmful byproducts 34 arsenic contamination 34 electromagnetic fields EMFs 34 chloramines 34 ashfall advisory 34 organic pollutants POPs 34 teragrams 34 glycol ethers 34 atrazine herbicide