Celebrate Air Conditioning Appreciation Week with this gallery  from Magnum Photos. Ever wonder about the water that drips down from air conditioners as an unwelcome sidewalk surprise when you’re walking to work? In 2011, Forrest Wickman looked into the reason why ACs are so leaky, and if there’s anything unsanitary about the water that’s dripping down on you. The original article is reprinted below. Walk down any city sidewalk on a hot summer day, and you're bound to get wet—and not just when it's raining. Water drips from window AC units, especially on muggy days, and this unpleasant drizzle can fall into your hair or even onto the lip of your morning coffee cup. Is all that dripping water sanitary? Yes, as a general rule. Most of the dripping from air conditioners is just condensed water vapor that comes from the air inside the building. Window air conditioners are designed to drain this water from the back, raining it down on any unsuspecting pedestrians below.

In most ways this water is exactly like rain (which also forms from condensed water vapor) or the moisture that collects on a cool can of soda, and it's typically no more harmful. However, in rare cases small amounts of water can be left to stagnate inside the air conditioner, making it a breeding ground for bacteria. On a hot and humid day, a window unit can drip up to 2 gallons of water, which accumulates on its evaporator coil as it cools and dehumidifies the air. (Very little condensation gathers on the exterior side of an AC, which tends to be warmer than the air around it.) This coil, like many plumbing pipes used for drinking water, is made of copper (which is also what makes air conditioners so heavy), and it's much cleaner than you might expect from looking at a dusty AC filter. While copper can be unhealthy in high doses, the condensate from air conditioners seems to be low in minerals and dissolved solids. In a properly functioning air conditioner, the water drips down from the coil into a condensate pan and then exits the unit through a drain or tube.

However, a clog in this drain or tube can leave a puddle to accumulate inside, which is an ideal environment for many types of harmful bacteria. how much is a 5 ton hvac unitIn particular, a 1976 outbreak of Legionnaires' disease was caused by bacteria that spread out of the air conditioning system at Philadelphia's Bellevue-Stratford Hotel. fan motor ac unit not working(That's how the disease got its name: Many of the victims were attending an American Legion convention.) recycle old ac unitWhile Legionella is known to thrive in the cooling towers of large air conditioning systems like the one at that Philadelphia hotel, it does not seem to grow in smaller units. Furthermore, dripping water isn't really stagnant, so it's extremely unlikely that the water raining down on pedestrians would be infected.

The water that drips from air conditioners is probably even safe for drinking. (It's certainly more potable than the drinking water in many countries.) Still, for the reasons mentioned above, it's best not to tilt your head back for a draft. If you're looking for a better use for your air conditioner's condensate, the Explainer recommends using it to water your plants. Got a question about today's news? Explainer thanks Douglas T. Reindl of the University of Wisconsin-Madison and Mark Sobsey of the University of North Carolina at Chapel Hill. Set LIST_ITEM_END_OF_LIST when list is at end of document. The LIST_ITEM_END_OF_LIST flag is an internal flag passed to renderers when rendering list items. It's normally set for the last item in the This change fixes the issue where that flag wasn't set in situations where the Markdown document ends with the list being the last block level item in it. The cases above detect and set LIST_ITEM_END_OF_LIST flag when the list

ends because another thing begins, but they miss it when the end of No tests here because this subtle internal behavior is hard to test and would require quite a bit of testing/mock infrastructure. Blackfriday is a Markdown processor implemented in Go. is paranoid about its input (so you can safely feed it user-supplied data), it is fast, it supports common extensions (tables, smart punctuation substitutions, etc.), and it is safe for all utf-8 HTML output is currently supported, along with SmartypantsAn experimental LaTeX output engine is also included. It started as a translation from C of Sundown. Blackfriday is compatible with Go 1. If you are using an older release of Go, consider using v1.1 of blackfriday, which was based on the last stable release of Go prior to Go 1. You can find it as a tagged commit on github. With Go 1 and git installed: will download, compile, and install the package into your $GOPATH

Alternatively, you can achieve the same if you import it into a project: and go get without parameters. For basic usage, it is as simple as getting your input into a byte This renders it with no extensions enabled. To get a more useful feature set, use this instead: Blackfriday itself does nothing to protect against malicious content. dealing with user-supplied markdown, we recommend running blackfriday's output through HTML sanitizer such as Here's an example of simple usage of blackfriday together with bluemonday: If you want to customize the set of options, first get a renderer (currently either the HTML or LaTeX output engines), then use it to call the more general Markdown function. For examples, see the implementations of MarkdownBasic and MarkdownCommon in You can also check out blackfriday-tool for a more complete example of how to use it. Download and install it using: This is a simple command-line tool that allows you to process a

markdown file using a standalone program. You can also browse the source directly on github if you are just looking for some example Note that if you have not already done so, installing blackfriday-tool will be sufficient to download and install blackfriday in addition to the tool itself. The tool binary will beThis is a statically-linked binary that can be copied to wherever you need it without worrying about dependencies and library versions. All features of Sundown are supported, including:The Markdown v1.0.3 test suite passes withWithout --tidy, the differences are mostly in whitespace and entity escaping, where blackfriday is more consistent and cleaner. Common extensions, including table support, fenced code blocks, autolinks, strikethroughs, non-strict emphasis, etc.Blackfriday is paranoid when parsing, making it safe to feed untrusted user input without fear of bad thingsThe test suite stress tests this and there are no

known inputs that make it crash. If you find one, please let me know and send me the input that does it. NOTE: "safety" in this context means runtime safety only. protect yourself against JavaScript injection in untrusted content, seeIt is fast enough to render on-demand in most web applications without having to cache the output.You can run multiple parsers in different goroutines without ill effect. There is no dependence on globalBlackfriday only depends on standard library packages in Go. The source code is pretty self-contained, so it is easy to add to any project, including Google App Engine projects.Output successfully validates using the W3C validation tool for HTML 4.01 and XHTML 1.0 Transitional. In addition to the standard markdown syntax, this package implements the following extensions:The _ character is commonly used inside words when discussing code, so having markdown interpret it as an emphasis command is usually the

Blackfriday lets you treat all emphasis markers as normal characters when they occur inside a word.Tables can be created by drawing them in the input using a simple syntax:In addition to the normal 4-space indentation to mark code blocks, you can explicitly mark them and supply a language (to make syntax highlighting simple). mark it like this: func getTrue() bool { You can use 3 or more backticks to mark the beginning of the block, and the same number to mark the end of the block.A simple definition list is made of a single-line term followed by a colon and the definition for that term. : Fluffy animal everyone likes : Vector of transmission for pictures of cats Terms must be separated from the previous definition by a blank line.A marker in the text that will become a superscript number; a footnote definition that will be placed in a list of footnotes at the end of the document. A footnote looks like this: This is a footnote.

[^1]: the footnote text.Blackfriday can find URLs that have not been explicitly marked as links and turn them into links.Use two tildes (~~) to mark text that should be crossed out.With this extension enabled (it is off by default in the MarkdownBasic and MarkdownCommon convenience functions), newlines in the input translate into line breaks inSmartypants-style punctuation substitution is supported, turning normal double- and single-quote marks into LaTeX-style dash parsing is an additional option, where -- is translated into –, and --- is translated intoThis differs from most smartypants processors, which turn a single hyphen into an ndash and a double hyphen into an Smart fractions, where anything that looks like a fraction is translated into suitable HTML (instead of just a few special cases like most smartypant processors). becomes ⁴⁄₅, which renders as Blackfriday is structured to allow alternative rendering engines.

are a few of note: provides a GitHub Flavored Markdown renderer with fenced code block highlighting, clickable header anchor links. It's not customizable, and its goal is to produce HTML output equivalent to the GitHub Markdown API endpoint, except the rendering is performed locally. LaTeX output: renders output as LaTeX. This is currently part of the main Blackfriday repository, but may be split into its own projectIf you are interested in owning and maintaining the LaTeX output component, please be in touch. It renders some basic documents, but is only experimental at thisIn particular, it does not do any inline escaping, so input that happens to look like LaTeX code will be passed through without Md2Vim: transforms markdown files into vimdoc format.It does not understand all unicode rules (about what constitutes a letter, a punctuation symbol, etc.), so it may fail to detect word boundaries correctly inIt is safe on all utf-8 input.