| Waiting period, it sometimes seems | 34 |
| Period in the earth's history | 33 |
| Longest division of time, in geology | 36 |
| It's comprised of ages and ages | 35 |
| Clock watcher's wait, seemingly | 35 |
| 365 billion days, astronomically | 32 |
| ___ Productions ("Skyfall" company) | 45 |
| What a houseguest's stay might feel like | 44 |
| Wait at the motor vehicle bureau, say | 37 |
| Two or more eras, in geologic time | 34 |
| Time spent calling call centers, seemingly | 42 |
| Time it seemingly takes to get a tax refund | 43 |
| Time in a waiting room, seemingly | 33 |
| Time between checks, for a freelancer, seemingly | 48 |
| The time of many billions of lives | 34 |
| Quasi-opposite of "flash" | 35 |
| One billion years, in geologic time | 35 |
| Many a doctor's office wait, seemingly | 42 |
| Length of a boring class, so it seems | 37 |
| Largest division of geologic time | 33 |
| James Bond film production company | 34 |
| It's over thirty quadrillion seconds long | 45 |
| It's made up of many periods | 32 |
| It's going to be quite a while | 34 |
| It lasts between four and five galactic years | 45 |
| It can be subdivided into periods | 33 |
| Impatient person's wait, seemingly | 38 |
| Immeasurably long period of time | 32 |
| Division of about one billion years | 35 |
| An extremely long period of time | 32 |
| About 525 trillion minutes, in astronomy | 40 |
| Units on the geologic time scale | 32 |
| Immeasurably long periods of time | 33 |
| Thousands and thousands of years | 32 |
| Mountains have developed over them | 34 |
| Indefinitely long periods of time | 33 |
| How long it takes canyons to form | 33 |
| Billion-year increments, in geology | 35 |
| "Rosy-fingered" goddess | 33 |
| Canon camera named for a goddess | 32 |
| Canon camera introduced in the 1980s | 36 |
| Winged goddess of Greek mythology | 33 |
| Volkswagen with a retractable hardtop | 37 |
| Volkswagen model named after a goddess | 38 |
| Tithonus' abductor, in Greek myth | 37 |
| She's a morning person in Greek legend | 42 |
| She changed a king into a grasshopper | 37 |
| Mythical mother of the four winds | 33 |
| Mother of the winds, in Greek myth | 34 |
| Mother of the stars and the winds | 33 |
| Morning dew is her tears, in mythology | 38 |
| In myth, her tears created the morning dew | 42 |
| Homer's saffron-robed goddess | 33 |
| Homer called her "rosy-fingered" | 42 |
| Hardtop convertible from Volkswagen | 35 |
| Goddess whose home was on the edge of Oceanus | 45 |
| Gates-of-heaven opener for Apollo | 33 |
| Driver of a four-horse chariot, in myth | 39 |
| "The commercial corporate jet" airline | 48 |
| "Saffron-robed" goddess, in Homer | 43 |
| Dye used in making red ink (Var.) | 33 |
| Org. concerned with climate change | 34 |
| They want to clear the air, briefly | 35 |
| Superfund administrator, briefly | 32 |
| Org. with a Pollution Prevention Grant | 38 |
| Org. that began the Energy Star program | 39 |
| Org. concerned with global warming | 34 |
| Gp. interested in clearing the air | 34 |
| Govt. org. with a flower in its logo | 36 |
| Agcy. twice headed by Ruckelshaus | 33 |
| William Ruckelshaus was its first head: Abbr. | 45 |
| Safe Drinking Water Act enforcer, for short | 43 |
| Org. with the blog Greenversations | 34 |
| Org. with an Office of Air and Radiation | 40 |
| Org. with air and water standards | 33 |
| Org. to be headed by Gina McCarthy, soon | 40 |
| Org. that's affiliated with fueleconomy.gov | 47 |
| Org. that tracks mercury emissions | 34 |
| Org. that oversees the Superfund | 32 |
| Org. that may be involved in a cleanup | 38 |
| Org. tasked with enforcing the Clean Air Act | 44 |
| Org. monitoring industrial wastes | 33 |
| Org. headed by W. D. Ruckelshaus | 32 |
| Org. headed by Lisa Perez Jackson | 33 |
| Org. created under the Nixon administration | 43 |
| Org. concerned with the BP oil spill | 36 |
| Org. concerned with safe drinking water | 39 |
| Org. concerned with mercury in fish | 35 |
| Org. concerned with hazardous waste | 35 |
| Org. concerned with greenhouse gases | 36 |
| Org. concerned with greenhouse gas | 34 |
| Office of Air and Radiation parent org. | 39 |
| National Exposure Research Lab org. | 35 |
| Its site has an Air Science page | 32 |
| It's got its standards: Abbr. | 33 |
| It's concerned with Hg emissions | 36 |
| It provides mileage ratings (abbr.) | 35 |
| Govt. org. in 'The Simpsons Movie' | 42 |
| Govt. "cleanup" agency | 32 |
| Fuel economy authority, for short | 33 |