Related by context. All words. (Click for frequent words.) 76 ozone 74 ozone smog 72 fine particle pollution 69 air pollution 68 ozone concentrations 67 particulate pollution 66 particle pollution 66 smog 64 fine particulate pollution 63 particulate matter 63 fine particulates 63 ozone pollutant 62 pollutant ozone 62 fine particulate matter 62 microscopic soot 60 PM#.# 60 particulates 59 nonattainment 59 pollutants 59 soot pollution 58 nitrogen oxides 58 nonattainment areas 58 pollutant 58 airborne pollutants 58 air toxics 57 fine particulate 57 smoggiest 57 Particle pollution 57 nonattainment designation 57 Nitrogen oxides 56 airborne particulates 56 nitrogen oxide 56 soot particles 56 Particulate pollution 55 ozone precursor 55 airborne particulate matter 55 pollution 55 Ambient Air 55 soot 55 nitrogen dioxide 55 pollutants emitted 54 ozone nonattainment 54 particulate 54 #,# butadiene 54 smog forming emissions 53 airborne soot 53 smog forming 53 coarse particulate matter 53 particulate concentrations 53 Sensitive Groups 53 smog forming pollution 53 tropospheric ozone 53 Nonattainment 53 PM# [003] 52 mercury emissions 52 pollutant emissions 52 Fine particulate 52 Liberty Clairton 52 Nitrogen dioxide 52 ozone particulates 52 nitrogen oxide emissions 52 Particulates 52 gaseous pollutants 52 smog forming pollutants 52 designated nonattainment 52 exceedences 52 Air Pollution 51 PM#s 51 airshed 51 particle concentrations 51 ozone particulate matter 51 emissions 51 Air Quality 51 tiny soot particles 51 mercury pollution 51 photochemical smog 51 diesel exhaust 51 SO2 emissions 51 EnviroFlash 50 particulate soot 50 nitrogen deposition 50 nitrous oxides 50 Ozone Alert 50 airborne pollutant 50 tailpipe emissions 50 greenhouse gases 50 Particulate matter 50 Sulfur dioxide 50 diesel particulates 50 sooty particles 50 Ozone Action 50 toxic pollutants 50 nitrogen oxides NOx 50 respiratory irritant 50 Toxic Release Inventory 49 Blowing dust 49 particulate matter PM 49 NOx emissions 49 sulfur dioxide pollution 49 airsheds 49 particulate emissions 49 PM# particles 49 soot smog 49 nitrogen oxide pollution 49 chloride concentrations 49 temperature inversions 49 Houston Galveston Brazoria 49 Nitrogen oxide 49 Urbaszewski 49 inhalable particles 49 particulate matter emissions 49 beachwater samples 49 mercury emitted 49 nitrogen oxides carbon monoxide 49 Diesel exhaust 49 ultrafine particles 49 NOX emissions 49 sulfur dioxide SO2 49 Tailpipe emissions 48 smog forming nitrogen oxides 48 indoor radon 48 greenhouse gases GHG 48 phosphorus pollution 48 Volatile organic compounds 48 NOx 48 exceedances 48 volatile organic compounds 48 sulfur dioxide 48 mercury 48 elevated radon 48 carbon monoxide hydrocarbons 48 VOCs 48 cockroach allergens 48 Smog 48 sulfur dioxide pollutant 48 diesel particulate matter 48 disinfection byproducts 48 carbon tetrachloride 47 stratospheric ozone 47 radon concentrations 47 emission 47 airborne particles 47 microcystins 47 atmospheric ozone 47 nitrogen oxide NOx emissions 47 THMs 47 particle soot 47 PAH concentrations 47 smokestack pollutants 47 anthropogenic greenhouse gases 47 carbon dioxide concentrations 47 particles PM#.# 47 carbon dioxide emissions 47 unhealthful 47 TTHMs 47 nitrogen dioxide NO2 47 Environmental Protection Agency 47 Pollutants 47 radon 47 carbon monoxide particulate matter 47 bioaccumulative 47 haloacetic acids 47 pollen counts 47 pollutant particles 47 hydrocarbons carbon monoxide 47 coarse particulates 47 nitrogen oxide emission 46 Rapid Transit ridership 46 tailpipe exhaust 46 smog advisories 46 lung irritant 46 sulfur dioxide nitrogen dioxide 46 ozone precursors 46 particulate pollutants 46 ozone attainment 46 asthma sufferers 46 Schkolnick 46 particulate matter soot 46 Fine particulates 46 haloacetic acid 46 relative humidities 46 microcystin 46 carbon monoxide sulfur dioxide 46 toxic pollutant 46 irritate lungs 46 smokestack emissions 46 ragweed pollen 46 greenhouse gas emissions 46 PAHs 46 sulfur dioxide emissions 46 exceedance 46 temperature inversion 46 NAAQS 46 microscopic soot particles 46 carbon monoxide nitrogen dioxide 46 AQMD 46 beachwater quality 46 nitrous oxide emissions 46 Particle Pollution 46 smoggy 46 weed pollen 46 smog soot 46 Breathing ozone 46 atmospheric CO2 levels 45 ozone nitrogen oxides 45 EPA 45 greenhouse gasses 45 Ozone 45 Air Pollution Control 45 carcinogen benzene 45 toxic chemicals 45 nitrous oxide emission 45 Clean Air 45 ozone nitrogen dioxide 45 Sulfur dioxide emissions 45 heat trapping carbon dioxide 45 atmospheric pollutants 45 Air Toxics 45 emmissions 45 greenhouse gas 45 GHGs 45 Nitrogen oxide emissions 45 fluorinated gases 45 airborne particulate 45 particulate matter SPM 45 aggravates respiratory 45 trihalomethane 45 formaldehyde carcinogen 45 Volatile Organic Compound VOC 45 odorless colorless gas 45 PM#.# NAAQS 45 nitrogen dioxide carbon monoxide 45 greenhouses gases 45 Carbon dioxide emission 45 coarse particles 45 acid rain 45 nitrate contamination 45 aggravates asthma 45 naturally occurring fluoride 45 nitrogen oxides emitted 45 RealFeel ® temperatures 45 phosphorus runoff 45 aerosol particles 44 Carbon dioxide emissions 44 greenhouse emissions 44 VOC emissions 44 trihalomethanes 44 respiratory illnesses 44 Sulphur dioxide 44 smoggiest regions 44 precipitation 44 pollutants sulfur dioxide 44 AB# mandates 44 Shawn Ferreria 44 mercury contamination 44 AIRNow 44 heat trapping gases 44 tetrachloroethene 44 polycyclic aromatic hydrocarbons 44 harmful pollutants 44 pCi L 44 Fecal coliform 44 tailpipe gases 44 foothills bordered 44 carbon monoxide nitrogen oxides 44 naturally occurring arsenic 44 chlorine byproducts 44 sulfur gases 44 Fecal bacteria 44 inversion layer 44 anthropogenic greenhouse gas 44 mold spores 44 Fine particle pollution 44 asthma chronic bronchitis 44 National Weather Service 44 oxidized mercury 44 ash 44 smog forming ozone 44 carbolic acid particles 44 HAAs 44 greenhouse gases emitted 44 respiratory irritants 44 sulfur dioxide carbon monoxide 44 smog forming compounds 44 heaviest precipitation 44 carbon dioxide 44 Strong northerly winds 44 ozone depletion 43 Pollutant 43 pollutant emission 43 mercury sulfur dioxide 43 relative humidity 43 carcinogen 43 nutrient runoff 43 sewer overflows 43 Index AQI 43 sun ultraviolet radiation 43 particulate matter PM# 43 tailpipe emission 43 manmade greenhouse gas 43 carbon disulfide 43 smog acid 43 pCi l 43 atmospheric deposition 43 polution 43 emit pollutants 43 groundwater withdrawals 43 smoggiest cities 43 NO2 43 Sulfur Dioxide 43 Emissions 43 exertion outdoors 43 Greenhouse gases 43 pine beetle outbreaks 43 emit sulfur dioxide 43 trichloramine 43 ozone depleting gases 43 airborne allergens 43 Smog Alert 43 prolonged exertion 43 polluted runoff 43 hexavalent chromium 43 nutrient pollution 43 exhaust emissions 43 SO2 43 gases emitted 43 humidex values 43 secondhand smoke 43 coal tar sealants 43 chemical ammonium perfluorooctanoate 43 Toxics Release Inventory 43 nitrogen NOx 43 nitrogen trifluoride 43 Quality Standards NAAQS 43 μg/m3 43 particulate emission 43 Freezing fog 43 smog forming nitrogen oxide 43 outdoor exertion 43 harmful tailpipe emissions 43 oVOCs 42 Daily Load TMDL 42 particulate matter sulfur dioxide 42 carbon monoxide 42 chlordane 42 Sulfur compounds 42 stormwater runoff 42 NOx emission 42 nitrate concentrations 42 Freeze Warning 42 GHG pollution 42 pesticide exposures 42 diesel particulate emissions 42 fecal bacteria 42 trihalomethanes THMs 42 tailpipe pollutants 42 smog forming chemicals 42 greenhouse gas emission 42 Janice Nolen 42 nonpoint source pollution 42 greenhouse gases GHGs 42 daytime highs 42 mercury potent neurotoxin 42 trichlorethylene 42 carcinogenic polycyclic aromatic hydrocarbons 42 allergens 42 Endocrine disruptors 42 fumigants 42 Colder temps 42 particulate matter nitrogen oxides 42 arsenic concentrations 42 dust pet dander 42 Particulate Matter PM 42 suspected carcinogen 42 Flash Flood Warnings 42 respirable suspended particulate matter 42 perchlorethylene 42 GHG emission 42 toxic vapors 42 carbon dioxide CO ² 42 indoor allergens 42 dissolved oxygen levels 42 nitrogen oxide sulfur dioxide 42 enterococcus bacteria 42 Localized flooding 42 algae blooms 42 fuel moistures 42 fecal coliform bacteria 42 sulfur dioxide SO2 nitrogen 42 flame retardant chemicals 42 phosphorus concentrations 42 coughing wheezing 42 Precipitation totals 42 naturally occurring radium 42 exhaust emission 42 chlorine residuals 42 heat trapping gases emitted 42 colder drier 42 tailpipe pollution 42 heat trapping greenhouse 42 smog forming gases 42 temperatures 42 Relative humidities 42 enterococcus 42 heavier snowfalls 42 aerosols 42 perchlorate 42 burning fossil fuels 42 benzene 42 Carbon dioxide CO2 42 Dense fog advisory 42 fecal coliform contamination 42 Ozone depletion 42 perchlorate contamination 42 stormwater pollution 42 Knozone 42 polyaromatic hydrocarbons 42 aggravate respiratory 42 Relative humidity 42 abnormally dry 42 wintry precipitation 42 organophosphate pesticides 42 carbon dioxide CO2 42 sulfur dioxide SOx 42 Gauderman 42 pCi L. 42 ozone NAAQS 42 humidities 42 Lung Association 42 fecal coliform 42 Air Pollutants 42 CO -2 emissions 41 gasoline vapors 41 toxaphene 41 Stephen Konarik meteorologist 41 Harmful algal blooms 41 AQHI 41 spontaneously ignite 41 humidity 41 Algae blooms 41 ug/m3 41 sulfur dioxide nitrogen oxide 41 groundwater contamination 41 patchy dense fog 41 foothill communities 41 PCBs dioxins 41 sulfur hexafluoride 41 asthma emphysema 41 Afternoon thunderstorms 41 mold spore counts 41 anthropogenic carbon dioxide 41 nutrient loading 41 CO ² emissions 41 ozone nonattainment area 41 disinfectant byproducts 41 indoor dampness 41 turbidity cloudiness 41 coal tar sealant 41 heat trapping 41 Toxics Release Inventory TRI 41 Standard NAAQS 41 deplete ozone 41 Keetch Byram Drought 41 contaminant 41 carbon emissions 41 deplete oxygen 41 atrazine herbicide 41 PFOA 41 TMDLs 41 PAH compounds 41 CO2 emissions 41 Showers thunderstorms 41 spokeswoman Cathy Milbourn 41 mold spore count 41 sulfur dioxide emission 41 atmospheric CO 41 algal toxins 41 sulfate aerosol 41 chemical vapors 41 acrolein 41 nitrous oxide NOx 41 sulfur dioxide mercury 41 Secondhand smoke exposure 41 Nitrogen Dioxide 41 asthma 41 cirrus clouds 41 ppb 41 VOC emission 41 allergy sufferers 41 reformulated gasoline 41 nonattainment designations 41 SO2 emission 41 toxicants 41 asthma bronchitis 41 Greenhouse gasses 41 pollutant concentrations 41 Particulate 41 spokeswoman Tressa Tillman 41 Pollution 41 sulphate aerosols 41 low relative humidities 41 contaminants 41 meltoff 41 nitrates 41 organic pollutants POPs 41 Carbon monoxide 41 emmission 41 Cheryl Heying 41 respiratory irritation 41 dissolved oxygen 41 TCE vapors 41 PBDEs 41 sulfuryl fluoride 41 Emission Standards 41 atmospheric aerosols 41 groundwater pumping 41 toxic algae blooms 41 unburned hydrocarbons carbon monoxide 41 respiratory ailments 41 Greenhouse Gas GHG emissions 41 #,# DCB 41 particulate matter PM#.# 41 colorless odorless poisonous 41 TMDL 41 carcinogens 41 stratospheric ozone depletion 41 Carbon monoxide CO 41 groundwater contaminant 41 pollen 41 emissons 41 particulate matter emitted 41 sewage spills 41 smokestack scrubbers 41 chloramines 41 stringent emission 41 SOx emissions 41 turbidity 41 pine pollen 41 heat trapping emissions 41 LCFS 41 airborne irritants 41 Forage availability 41 Carbon dioxide concentrations 41 Warmer temps 41 exceedence 41 heavily polluted 41 sweatiest cities 41 VOCs emitted 41 vapor intrusion 41 chlorpyrifos 41 nitrogen oxides NOx emissions 41 degrees Centigrade #.#F 41 spokeswoman Davina Marraccini 41 Particulate emissions 41 low humidities 41 load TMDL 41 silica dust 41 LaCavera 40 hotter drier weather 40 particles emitted 40 nitrogen oxide NOX 40 spokeswoman Phillippa Cannon 40 cockroach allergen 40 wind chill temperatures 40 creosote buildup 40 global warming gases 40 hydrogen sulfide 40 pine beetle outbreak 40 9NEWS Meteorologist Marty Coniglio 40 GHG emissions 40 nitrous oxide N2O 40 allergenic pollen 40 EPA Administrator 40 PFOS 40 trichloroethene 40 trichlorethylene TCE 40 reduce visibilities 40 Hydrogen sulfide 40 Burn Ban 40 Weather Service 40 solvent vapors 40 Sewer overflows 40 Emissions Vehicle AT PZEV 40 Nighttime temperatures 40 upper troposphere 40 Superfund cleanup 40 wind chill advisories 40 Excessive Heat 40 volcanic haze 40 polluted groundwater 40 Slightly cooler 40 ozone depleting compounds 40 Abnormally dry 40 Dense fog 40 tiny airborne particles 40 smoky skies 40 GhG emissions 40 Contrails 40 Ragweed pollen 40 rainfall totals 40 respirable particles 40 soot emitted 40 microgram 40 ozone depleting substances 40 aerosol concentrations 40 Omitt 40 microcystis 40 Smog Standards 40 nitrogen dioxides 40 Volatile Organic Compounds VOC 40 Nitrogen Oxide NOx 40 airborne toxins 40 springtime ozone 40 ozone depleting chemicals 40 MACT standards 40 lung irritation 40 rainfall 40 benzo pyrene 40 allergy inducing 40 Red Flag Warning 40 secondhand smoke exposure 40 ocean acidity 40 Cooler drier 40 Adequate ventilation 40 bio accumulative 40 seasonally unadjusted jobless 40 Freezing temps 40 phosphorus 40 TCEQ 40 hydrocarbon vapors 40 sulphate particles 40 Jared Blumenfeld administrator 40 Warmer drier weather 40 diesel particulate 40 pesticide drift 40 carbon emitted 40 Severe thunderstorm warning 40 CO2 SO2 40 reducing visibilities 40 chemical perfluorooctanoic acid PFOA 40 EPA Toxics Release 40 Global Warming Potential GWP 40 specialist Stuart Seto 40 Cooler temps 40 mercury vapors 40 MtBE 40 reduced visibilities 40 pesticide poisonings 40 aggravate asthma 40 Sadredin 40 GHG concentrations 40 airmass 40 gases 40 invasive meningococcal disease 40 Winter Weather Advisories 40 chloramine 40 snowfall accumulations 40 bark beetle infestations 40 polluted 40 Volatile Organic Compounds 40 allergen 40 Greenville Oconee Pickens 40 PANHANDLE Temperatures 40 ghg emissions 40 groundwater 40 greenhouse gas concentrations 40 Warmer drier 40 assimilative capacity 40 Bq/m3 40 sulfur trioxide 40 respirable suspended 40 nitrogen oxides particulate matter 40 Heavier snow 40 Soil moisture 40 frost advisories 40 OWBs 40 PM#.# particles 40 microscopic particles 40 hottest driest 40 wintery precipitation 40 methyl mercury 40 teragrams 39 sootiest 39 sewage overflows 39 Visibilities 39 ammonia nitrogen 39 oxygen depletion 39 global warming gasses 39 pollutant discharge 39 diazinon 39 USEPA 39 Higher elevations 39 dissolved solids 39 regulating GHGs 39 respirable suspended particulates 39 C# emissions 39 respiratory illness 39 perfluorinated compounds 39 nitrogen dioxide emissions 39 marine biotoxin 39 PFOAs 39 ultraviolet UV radiation 39 heat trapping gasses 39 Greenhouse Gas Inventory 39 pollutions 39 patchy frost 39 Snow flurries 39 woodstoves 39 perfluorochemicals PFCs 39 algae bloom 39 tetrachlorethylene 39 CO2 39 gaseous emissions 39 Air Pollutants NESHAP 39 carcinogenic compounds 39 driest summers 39 benzene carcinogen 39 harmful algal blooms 39 mosquito infestation 39 hydrogen sulfide ammonia 39 Carbon dioxide CO2 emissions 39 Hazy sunshine 39 nonpoint pollution 39 tobacco specific nitrosamines 39 wastewater discharge 39 airborne contaminants 39 Co2 emissions 39 Slightly warmer 39 e coli bacteria 39 Carbon dioxide 39 wetter winters 39 polybrominated diphenyl ethers PBDEs 39 Emissions Inventory 39 NOx nitrogen oxide 39 Warm moist 39 Dissolved oxygen levels 39 maximum contaminant 39 Alamance Chatham 39 Algal blooms 39 Methylmercury 39 ozone layer depletion 39 grass pollen 39 Severe thunderstorm watches 39 spokeswoman Heidi Griesmer 39 DDT pesticide banned 39 rotten egg odor 39 Sewage spills 39 acrylamide 39 pedestrian fatalities 39 Feral swine 39 allergens irritants 39 2C #.#F 39 nonroad diesel engines 39 Stachybotrys 39 polluted stormwater runoff 39 manmade CO2 emissions 39 microwaving popcorn 39 Excess nitrogen 39 micrograms 39 PCBs polychlorinated biphenyls 39 PAHs polycyclic aromatic hydrocarbons 39 carbondioxide emissions 39 Scattered storms 39 VOCs volatile organic compounds 39 Southerly winds 39 BAAQMD 39 smoggy skies 39 mountain snowpacks 39 Wind Advisories 39 mountain plover 39 sulfur dioxides 39 sulfur dioxide SO2 emissions 39 Isolated thunderstorms 39 sanitary sewer overflows 39 troposphere 39 emission reductions 39 RSPM 39 trihalomethane levels 39 ammonia hydrogen sulfide 39 atmospheric methane 39 Prescribed burns 39 infants Sundlof 39 sulfur dioxide nitrogen oxides 39 PM# particulate matter 39 Cow burps 39 microscopic airborne particles 39 harmful vapors 39 mercury polluter 39 ozone O3 39 harmful algae blooms 39 damaging ultraviolet rays 39 heat trapping pollutants 39 toxic algal blooms 39 Polluted runoff 39 AccuWeather forecasters 39 reduce SO2 emissions 39 smoggier 39 contaminating groundwater 39 particulate matter carbon monoxide 39 Nitrogen Oxide 39 pollutant discharges 39 wood stoves 39 algal blooms 39 potent greenhouse gas 39 Polycyclic aromatic hydrocarbons 39 heatwaves floods droughts 39 asthmatics 39 coldest temperature 39 Glitto 39 Nitrogen Oxides 39 LRAPA 39 exhaust fumes 39 carbon monoxide nitrogen oxide 39 nutrient loadings 39 dischargers 39 upper elevations 39 anthropogenic CO2 emissions 39 La Niña pattern 39 gradual cooldown 39 ragweed 39 warming gases 39 dioxin PCBs 39 hoofed critters 39 heaviest accumulations 39 barium cadmium 39 toxics 39 indoor wood stoves 39 Nitrogen NOx 39 harmful chemicals 39 Elevated arsenic 39 PennEnvironment 39 pyrethroids 39 allergy triggers 39 Particulate Matter 39 sulfolane 39 wind chill advisory 39 bronchitis asthma 39 Dawn Stoltzfus 39 nitrogen oxide NOx 39 lampblack 39 Heat Advisories 39 stachybotrys 39 PBDE chemicals 39 Cathy Milbourn 39 NWS forecasters 39 global warming 39 Unseasonably warm 39 midlatitudes 39 lowland flooding 39 Wintry precipitation 39 cat allergen 39 blackwater streams 39 snowpack 39 ultra violet radiation 39 soot particulates 39 ice jams 39 Peter Iwanowicz 39 diesel fumes 39 diacetyl vapors 39 pollens 39 prevailing westerly winds 39 particulate opacity mercury 38 droplet nuclei 38 nighttime lows 38 Vapor intrusion 38 organophosphate exposure 38 nighttime temperatures 38 Blowing snow 38 water vapor 38 Scorching temperatures 38 sulfuric dioxide 38 pumpage 38 winterlike weather 38 fluorinated greenhouse gases 38 sulfur dioxide nitrogen 38 Wayne Nastri administrator 38 invisible odorless tasteless 38 ultrafine particle 38 pollen.com 38 abrasive volcanic ash 38 lawn watering 38 atmospheric CO2 38 Dissolved oxygen 38 smog blanketing 38 Northerly winds 38 vinyl chloride 38 anthropogenic interference 38 harmful gases 38 CO -2 38 alachlor 38 Mold spores 38 concentrations 38 Carbon tetrachloride 38 lung ailments 38 cedar pollen 38 reformulated gasoline RFG 38 Enviro Log firelogs 38 thirdhand smoke 38 polluting 38 chromium 38 Radon Action Month 38 condensation nuclei 38 smoggiest skies 38 Pollen counts 38 carbon dioxide methane nitrous 38 ammonium perfluorooctanoate 38 reburn 38 Snowstorm snarls 38 Iarrapino 38 Greenland glaciers melt 38 combustion byproducts 38 MICHAEL REYNOLDS 38 rapid snowmelt 38 carbon dioxide CO2 emissions 38 mosquito infestations 38 formaldehyde 38 snowcover 38 Stan Meiburg 38 carbon dioxide nitrous oxide 38 Dangerous wind chills 38 arsenic 38 Hazy skies 38 NWS meteorologists 38 dust mite allergen 38 Accumulating snow 38 Humidex 38 BLLs 38 Rubbertown 38 Schladow 38 Peanut allergies 38 crystalline silica 38 Fargo ND Wahpeton ND 38 lobbyist Bob Dinneen 38 drier warmer 38 ice accumulations 38 incomplete combustion 38 Unseasonably 38 Dimitri Stanich spokesman 38 Snowpack 38 Volatile Organic Compounds VOCs 38 CO2 concentrations 38 VOCs Volatile Organic Compounds 38 Carbon Monoxide CO 38 Secondhand smoke 38 perfluorocarbons 38 LAKE YUCATAN 38 sulfur gasses 38 Diesel Collaborative 38 stormwater discharges 38 nonroad diesel 38 persistent wheezing 38 hotter drier 38 El Nino warming 38 Ultrafine particles 38 total coliforms 38 atmospheric moisture 38 moisture 38 drought parching 38 catastrophic wildfires 38 perfluorochemicals 38 Thermometers registered 38 Enterococcus bacteria 38 sulfur oxide 38 wastewater overflows 38 asthma triggers 38 #.#C #.#C 38 pollen ragweed 38 cleaner burning 38 cooler drier 38 E. coli bacteria 38 phosphorus fertilizers 38 sulfur fumes 38 disinfection byproducts DBPs 38 stricter emission 38 Nipomo Mesa 38 methane CH4 38 toxic substances 38 Gerapetritis 38 seasonably mild 38 Keith Overcash 38 TTHM 38 Indoor Air 38 Dust mites 38 antidegradation 38 PDBEs 38 fluorotelomers 38 pollen allergies 38 deca BDE 38 bark beetle epidemic 38 chromium VI 38 groundwater depletion 38 Hard Freeze Warning 38 Pre monsoon rains 38 Controlled burns 38 secondhand tobacco 38 Excessive moisture 38 sewage discharges 38 polluting groundwater 38 HABs